Advertisement

Therapeutic cancer vaccines: From biological mechanisms and engineering to ongoing clinical trials

      Highlights

      • FDA anti-SARS-CoV-2 vaccines propel therapeutic anti-cancer vaccine platforms.
      • Simple mRNA structure alterations in vaccines gives more engineering flexibility.
      • Vaccines stability, antigen translation and delivery through lipid nanoparticles.
      • Nucleic-acid, peptide, cellular, personalized neoantigen vaccines investigations.
      • Comprehensively review of key ongoing clinical trials.

      Abstract

      Therapeutic vaccines are currently at the forefront of medical innovation. Various endeavors have been made to develop more consolidated approaches to producing nucleic acid-based vaccines, both DNA and mRNA vaccines. These innovations have continued to propel therapeutic platforms forward, especially for mRNA vaccines, after the successes that drove emergency FDA approval of two mRNA vaccines against SARS-CoV-2. These vaccines use modified mRNAs and lipid nanoparticles to improve stability, antigen translation, and delivery by evading innate immune activation. Simple alterations of mRNA structure- such as non-replicating, modified, or self-amplifying mRNAs- can provide flexibility for future vaccine development. For protein vaccines, the use of long synthetic peptides of tumor antigens instead of short peptides has further enhanced antigen delivery success and peptide stability. Efforts to identify and target neoantigens instead of antigens shared between tumor cells and normal cells have also improved protein-based vaccines. Other approaches use inactivated patient-derived tumor cells to elicit immune responses, or purified tumor antigens are given to patient-derived dendritic cells that are activated in vitro prior to reinjection. This review will discuss recent developments in therapeutic cancer vaccines such as, mode of action and engineering new types of anticancer vaccines, in order to summarize the latest preclinical and clinical data for further discussion of ongoing clinical endeavors in the field.

      Keywords

      Abbreviations:

      NSCL (non-small cell lung cancer), SCC (squamous cell cancer), TNBC (triple negative breast cancer), mCRC (metastatic colorectal cancer), mPC (metastatic pancreatic cancer), TNBC (triple negative breast cancer, SCLC, small cell lung cancer), TAA (tumor-associated antigen), LNP (lipid nanoparticle), SNL (synthetic long peptide), MHC I and MHC II (Major Histocompatibility Complex I and II), DC (Dendritic Cells), SAM (virus-derived self-amplifying mRNAs), i.d. (intradermal), i.m. (intramuscular), i.n. (intranodal), i.v. (intravenous), s.c. (subcutaneous), FDA (Federal and Drug Administration), SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), TME (tumor micro environment), Tregs (regulatory T cells), ROS (reactive oxygen species), SAM (self-amplifying mRNAs), IVT (synthesized through in vitro transcription), TAAs (abnormally expressed proteins), APC (antigen-presenting cells), ORF (open reading frame), UTR (untranslated region), TLR (Toll-like receptors), TCR (T-cell receptor), HPV (human papillomavirus), VLP (targets virus-like particles), VSV (vesicular stomatitis virus), HNPCC (hereditary non-polyposis colorectal cancer), MSH-2 (mouse model for the lynch syndrome), PD-1/PD-L1 (programmed death protein-1/ligand1), NAP (Naproxen), CTLA-4 (cytotoxic T-lymphocyte antigen 4), VEGFR (vascular endothelial growth factor receptor), MDSCs (myeloid-derived suppressor cells), DC-IL12-OVA (DC-based vaccine expressing IL-12, pulsed with OVA-peptide), CEA (carcinoembryogenic antigen)

      Background

      Cancer is a significant health problem, with nearly 10 million deaths every year [
      • Sung H.
      • Ferlay J.
      • Siegel R.L.
      • Laversanne M.
      • Soerjomataram I.
      • Jemal A.
      • et al.
      Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries.
      ]. Besides protecting the organism from pathogens, the immune system's role is also useful for surveying the body to maintain cellular homeostasis. However, tumor cells can escape immune surveillance either by a selection of non-immunogenic tumor cell variants (immunoselection) or by actively suppressing immune response (immunesubversion)[
      • Zitvogel L.
      • Tesniere A.
      • Kroemer G.
      Cancer despite immunosurveillance: immunoselection and immunosubversion.
      ]. Advancements in immunotherapy have brought forth new potential therapies and prophylactic treatments that could lead to anticancer vaccines. Tumors display on their surface specific proteins generated when certain mutations occur in tumor DNA, and these proteins are called neoantigens. The body can generate an immune response against cancer cells through the help of neoantigens. Therefore, artificially triggering an immune response against tumor neoantigens constitutes the foundation for vaccines against tumors. Neoantigens are newly formed antigens that the immune system has not previously recognized. Neoantigens can arise from somatic mutation, alternative splicing, or viral proteins.
      Latest vaccine-engineering strategies include administration of antigens as inactivated tumor cell extracts, purified mutated tumor proteins, or DNA and mRNA for endogenous production of tumor antigens, combined with various adjuvants and systems of delivery [
      • Duarte J.H.
      Individualized neoantigen vaccines.
      ]. Two major two challenges to the development of cancer vaccines are the identification of neoantigens and the generation of new molecular epitopes recognized as foreign by the immune system to elicit a robust immune response against tumor cells. Results from ongoing clinical trials corroborate the information on therapeutic anticancer vaccine safety, with some studies indicating a potential efficacy.
      This review focuses on recent advancements in therapeutic cancer vaccines, going from latest vaccine technologies, identification of neo-antigens methods, to ongoing investigations in animals and humans.

      Cancer vaccines: from biological mechanisms to engineering

      Historically, vaccines are used to prevent diseases caused by infectious pathogens. Present-day vaccines are expanding to cancer as well. Early cancer therapeutic vaccines failed to amplify de novo T cell responses primarily because they targeted abnormally expressed tumor-associated antigens proteins (TAAs) or self-proteins on tumor cells [
      • Zamora A.E.
      • Crawford J.C.
      • Thomas P.G.
      Hitting the target: how T cells detect and eliminate tumors.
      ]. Therapeutic cancer neoantigen strategies are highly advantageous since they home on an antigen while preventing central and peripheral tolerance and potential ‘off-target’ tissue damage observed in previous TAA-targeting strategies [
      • Pedersen S.R.
      • Sørensen M.R.
      • Buus S.
      • Christensen J.P.
      • Thomsen A.R.
      Comparison of Vaccine-Induced Effector CD8 T Cell Responses Directed against Self- and Non–Self-Tumor Antigens: Implications for Cancer Immunotherapy.
      ].
      One critical step to developing a cancer vaccine is identifying and selecting appropriate neoantigens or neoepitope targets expressed exclusively by cancer cells. The immune system readily mounts a CD4+ and CD8+ T cell response to foreign proteins but tolerates self-proteins retained by cancer [
      • Hollingsworth R.E.
      • Jansen K.
      Turning the corner on therapeutic cancer vaccines.
      ]. Generally, antigens with a heavy mutational burden make neoantigen identification more accessible and more likely to result in a tumor cell-specific immune response.
      Another challenge lies with the tumor microenvironment (TME), which has many adverse qualities such as generation of hypoxia, nutrient depletion, low pH, an increase of reactive oxygen species (ROS), and a high number of regulatory T cells (Tregs). Also, solid tumors have other barriers such as tumor fibroblasts (fibrotic extracellular matrix), myeloid suppressor cells, and Tregs that further reduce the number of tumor-infiltrating T cells [
      • Belli C.
      • Trapani D.
      • Viale G.
      • D'Amico P.
      • Duso B.A.
      • Della Vigna P.
      • et al.
      Targeting the microenvironment in solid tumors.
      ,
      • Vedenko A.
      • Panara K.
      • Goldstein G.
      • Ramasamy R.
      • Arora H.
      Tumor microenvironment and nitric oxide: Concepts and mechanisms.
      ,
      • Roma-Rodrigues C.
      • Mendes R.
      • Baptista P.
      • Fernandes A.
      Targeting tumor microenvironment for cancer therapy.
      ]. Other limitations include low tumor mutational burden, antigen escape, and antigen-presenting cells (APCs) ability. Advancements in immunotherapy have brought forth new potential therapies and prophylactic treatments that could lead to anticancer vaccines. Tumors display on their surface specific proteins generated when certain mutations occur in tumor DNA, and these proteins are called neoantigens. Vaccines with effective delivery methods, adjuvants, and appropriate antigens can potentially overcome these immunosuppressive obstacles. The most common types of therapeutic cancer vaccines that have been designed are nucleic acid vaccine (RNA or DNA), long synthetic peptide (SLP) vaccine, and cellular vaccine (tumor cell or on dendritic cell (DC)-based) (Fig. 1) [
      • Peng M.
      • Mo Y.
      • Wang Y.
      • Wu P.
      • Zhang Y.
      • Xiong F.
      • et al.
      Neoantigen vaccine: An emerging tumor immunotherapy.
      ,
      • Jou J.
      • Harrington K.J.
      • Zocca M.B.
      • Ehrnrooth E.
      • Cohen E.E.W.
      The changing landscape of therapeutic cancer vaccines-novel platforms and neoantigen identification.
      ].
      Figure thumbnail gr1
      Fig. 1The Main Types of Cancer Therapeutic Vaccines: Cancer vaccines primarily deliver antigens either nucleic acids, proteins, peptides, or patient-derived cells. Within nucleic acid-based vaccines, RNA has various approaches that differ with RNA structure manipulation and delivery compared to DNA, which is restricted by exclusively relying on plasmids to deliver antigen-encoding genetic materials. Both mRNA and DNA are taken up by cells and eventually translated into protein antigens APCs present to activate T cells. Cellular vaccines depend on patient-derived cells to deliver isolated tumor cells that are killed, or the patient’s DCs are activated in vitro with purified tumor antigens before reinjection. All therapeutic cancer vaccine types aim for antigen presentation followed by T cell activation and tumor rejection. Abbreviations: DC, Dendritic Cells; SAM, virus-derived self-amplifying mRNAs; SLP, synthetic long peptide.

      Nucleic Acid-based vaccines

      mRNA encodes target antigens expressed after administered mRNA is efficiently taken up and translated by local cells. This factor is beneficial for making mRNA available as an off-the-shelf cancer vaccine and for personalized neoantigen vaccination [
      • Polack F.P.
      • Thomas S.J.
      • Kitchin N.
      • Absalon J.
      • Gurtman A.
      • Lockhart S.
      • et al.
      Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine.
      ]. Another significant advantage is that mRNA encoded proteins can undergo post-translation modifications such as glycosylation, acetylation, methylation, or phosphorylation to become mature folded proteins, an essential condition to be appropriately antigenic. Previously, non-formulated or “naked” mRNA injection was shown to deliver vaccine components to the lymph nodes of mice. It also was observed that RNA directly injected into lymph node tissue effectively targets APCs and promotes high IL-12 secretion and expression of CD86 on DCs. This, in turn, promoted active proliferation and infiltration of CD8+ T and CD4+ T cells in lymph node tissue compared to controls [
      • Kreiter S.
      • Selmi A.
      • Diken M.
      • Koslowski M.
      • Britten C.M.
      • Huber C.
      • et al.
      Intranodal vaccination with naked antigen-encoding RNA elicits potent prophylactic and therapeutic antitumoral immunity.
      ]. Other methods include injecting liposome-encapsulated mRNA to increase adjuvanticity, or injecting self-adjuvanted RNA to promote cellular and humoral responses and Th1 and Th2 cell activation [
      • Kallen K.-J.
      • Heidenreich R.
      • Schnee M.
      • Petsch B.
      • Schlake T.
      • Thess A.
      • et al.
      A novel, disruptive vaccination technology: Self-adjuvanted RNActive ® vaccines.
      ]. Self-adjuvanted mRNA molecules are mRNAs whose encoded protein expression has been enhanced by 4–5 orders of magnitude by modification of nucleotide sequences with naturally occurring nucleotides (A/G/C/U) that do not affect primary aminoacid sequence. In addition, they are complexed with protamine, thus activate immune system by the involvement of toll-like receptor (TLR) 7. Self-adjuvanted RNA vaccines induce strong, balanced immune responses comprising humoral and cellular responses, effector and memory responses, and also activate important subpopulations of immune cells such as Th1 and Th2 cells [
      • Kallen K.-J.
      • Heidenreich R.
      • Schnee M.
      • Petsch B.
      • Schlake T.
      • Thess A.
      • et al.
      A novel, disruptive vaccination technology: Self-adjuvanted RNActive ® vaccines.
      ].
      Recently, a new promising platform called the KISIMA vaccine can select tumor antigen, makes cell-penetrating peptides to improve antigen delivery and epitopes presentation and finally, it uses TLR2/4 agonist as self-adjuvant. KISIMA was used in a study to produce a vaccine against achaete-scute family bHLH transcription factor 2 (Ascl2), an antigen found in early colon cancer. The vaccine could reduce colon tumor formation by stimulation of an antitumor immune response. Combining this vaccine with anti-PD-1, significantly reduced development of colon adenomas and macroadenomas, vs. negative controls, and may be used in patients at high-risk of incurring it [
      • Belnoue E.
      • Leystra A.A.
      • Carboni S.
      • Cooper H.S.
      • Macedo R.T.
      • Harvey K.N.
      • et al.
      Novel Protein-Based Vaccine against Self-Antigen Reduces the Formation of Sporadic Colon Adenomas in Mice.
      ].
      The United States Food and Drug Administration (US FDA) has recently approved lipid nanoparticles (LNP)-loaded mRNA for COVID-19 [
      • Polack F.P.
      • Thomas S.J.
      • Kitchin N.
      • Absalon J.
      • Gurtman A.
      • Lockhart S.
      • et al.
      Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine.
      ,
      • Baden L.R.
      • El Sahly H.M.
      • Essink B.
      • Kotloff K.
      • Frey S.
      • Novak R.
      • et al.
      Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine.
      ]. Currently, three types of LNP-loaded RNA vaccines are being studied in clinical trials for solid tumors: modified or unmodified non-replicating mRNA, and virus-derived self-amplifying mRNAs (SAM). Both non-replicating mRNA and SAM have been synthesized through in vitro transcription (IVT).
      IVT uses a bacteriophage RNA polymerase and DNA template for target antigen sequences to synthesize RNA cell-free. This method has proven easy for large-scale production of eukaryotic-like mRNAs, which contain an open reading frame (ORF) for a target antigen, flanked by 5′ and 3′ untranslated regions (UTR) bearing a 5′ 7-methylguanosine cap and 3′ poly adenine poly(A) tail. The poly(A) tail is transcribed from DNA templates or is added post-IVT by enzymes. Non-replicating mRNAs contain optimized 3′ and 5′ UTR and the ORF target antigen sequence, but not additional sequences for RNA replication (i.e., the viral replication machinery). Therefore, these mRNA sequences cannot self-replicate [
      • Wadhwa A.
      • Aljabbari A.
      • Lokras A.
      • Foged C.
      • Thakur A.
      Opportunities and Challenges in the Delivery of mRNA-Based Vaccines.
      ].
      SAM contains two ORFs, one encoding targeted antigen sequence, while the other machinery for viral replication is to support intracellular RNA amplification. After internalization, SAM enters the cytosol to be replicated or transcribed in mRNA and translated into proteins by ribosomes. Following translation and post-translational modification, the protein is folded and becomes functional [
      • Pardi N.
      • Hogan M.J.
      • Porter F.W.
      • Weissman D.
      mRNA vaccines — a new era in vaccinology.
      ].
      Modified mRNAs containing pseudo nucleotides such as, 1-methylpseudouridine, 5-methylcytidine, or N4-aceylcytidine to replace uridine and cytidine, improve not only translational efficiency and stability of the mRNA but also increase immune response potency [
      • Miao L.
      • Zhang Y.
      • Huang L.
      mRNA vaccine for cancer immunotherapy.
      ]. Karikó et al. found that modified nucleoside mRNAs decreased innate immunity by reducing the activation of RNA sensors such as Toll-like receptors (TLR) and RNA-dependent protein kinase (PKR). Interestingly, it was previously observed that reduced innate immune activation prevents abolition of mRNA translation into proteins. It should be noted that the phage polymerase contained in IVT can yield short RNA contaminants, which promote innate immunity by activating intracellular PRRs. However, purification by high-performance liquid chromatography (HPLC), permits the recovery of mRNA that decreases inflammatory cytokines activating innate immunity [
      • Karikó K.
      • Muramatsu H.
      • Ludwig J.
      • Weissman D.
      Generating the optimal mRNA for therapy: HPLC purification eliminates immune activation and improves translation of nucleoside-modified, protein-encoding mRNA.
      ,
      • Karikó K.
      • Buckstein M.
      • Ni H.
      • Weissman D.
      Suppression of RNA Recognition by Toll-like Receptors: The Impact of Nucleoside Modification and the Evolutionary Origin of RNA.
      ,
      • Karikó K.
      • Muramatsu H.
      • Welsh F.A.
      • Ludwig J.
      • Kato H.
      • Akira S.
      • et al.
      Incorporation of Pseudouridine Into mRNA Yields Superior Nonimmunogenic Vector With Increased Translational Capacity and Biological Stability.
      ]. In general, mRNA is an innovative and powerful cancer vaccine platform currently tested for cancer vaccination after recent advances in the field.
      DNA vaccines contain closed circular DNA plasmids of bacterial origin encoding desired antigens, which are transcribed into mRNAs and translated to proteins to induce antigen-specific immune responses. Like RNA vaccines, DNA vaccines promote humoral and cellular responses specific to target antigens. In addition, bacterial DNA stimulates TLRs or membrane-bound receptors that are critical in aiding DCs, B cells, and natural killer cells in recognizing pathogen-associated molecular patterns [
      • Yang B.
      • Jeang J.
      • Yang A.
      • Wu T.C.
      • Hung C.F.
      DNA vaccine for cancer immunotherapy.
      ]. This leads to a pro-inflammatory response cascade with cytokine production. Gardasil (Merck) is one well-known vaccine quadrivalent, HPV L1 virus-like particle (VLP) recombinant vaccine, which targets oncogenic subtypes of human papillomavirus (HPV) through the production of HPV-neutralizing antibodies. The first Gardasil vaccine protected against HPV types 6, 11 and 18. Currently, Gardasil-9 vaccine contains HPV 6, 11, 16, 18, 31, 33, 45, 52, and 58. The VLPs of Gardasil-9 are generated through the self-assembly of 360 copies of the L1 major capsid protein of the virus. Gardasil-9 VLP vaccine has been approved for use in the US against nine HPV strains and may give protection of 80% of cervical cancers [
      • Singhal P.
      • Marfatia Y.S.
      Human papillomavirus vaccine.
      ,
      • Monsonégo J.
      Prévention du cancer du col utérin : enjeux et perspectives de la vaccination antipapillomavirus.
      ]. Although the current subunit HPV vaccination provides effective prophylaxis, they do not eradicate existing infections. Therefore, other HPV vaccination strategies have begun evaluation. DNA vaccination targeting HPV proteins E6 and E7, both associated with HPV 16 and 18, results in poor immunogenicity, possibly because the virus evades host recognition [
      • Peng S.
      • Ferrall L.
      • Gaillard S.
      • Wang C.
      • Chi W.-Y.
      • Huang C.-H.
      • et al.
      Development of DNA Vaccine Targeting E6 and E7 Proteins of Human Papillomavirus 16 (HPV16) and HPV18 for Immunotherapy in Combination with Recombinant Vaccinia Boost and PD-1 Antibody.
      ]. To overcome this obstacle, DNA vaccination is combined with other immunotherapies. Recently, Peng et al. tested a DNA vaccine that targets E6 and E7 HPV proteins combined with PD-1 blockade in mice. Results indicated that combined therapy led to significantly prolonged survival time [
      • Peng S.
      • Ferrall L.
      • Gaillard S.
      • Wang C.
      • Chi W.-Y.
      • Huang C.-H.
      • et al.
      Development of DNA Vaccine Targeting E6 and E7 Proteins of Human Papillomavirus 16 (HPV16) and HPV18 for Immunotherapy in Combination with Recombinant Vaccinia Boost and PD-1 Antibody.
      ]. One type of DNA vaccine currently undergoing preclinical investigation is chimeric DNA vaccines, which encode xenogeneic antigens, homologous with the self-orthologue, but originated from a different species [
      • Strioga M.M.
      • Darinskas A.
      • Pasukoniene V.
      • Mlynska A.
      • Ostapenko V.
      • Schijns V.
      Xenogeneic therapeutic cancer vaccines as breakers of immune tolerance for clinical application: To use or not to use?.
      ]. The xenogeneic antigens are recognized as foreign, and may help override immune tolerance for TAAs that are recognized as self-antigens. Quaglino et al. designed a xenogeneic vaccine that consisted of a plasmid encoding chimeric rat/human ErbB2 proteins, which was administered to mice with ErbB2+ mammary tumors [
      • Quaglino E.
      • Riccardo F.
      • Macagno M.
      • Bandini S.
      • Cojoca R.
      • Ercole E.
      • et al.
      Chimeric DNA Vaccines against ErbB2+ Carcinomas: From Mice to Humans.
      ]. ErbB2 is an epidermal growth factor often highly displayed on some colorectal, pancreatic, endometrial, gastric, and breast cancers [
      • English D.P.
      • Roque D.M.
      • Santin A.D.
      HER2 Expression Beyond Breast Cancer: Therapeutic Implications for Gynecologic Malignancies.
      ]. Results indicated that the chimeric/xenogeneic vaccine induced more robust antitumor responses than autologous controls [
      • Lopes A.
      • Vandermeulen G.
      • Préat V.
      Cancer DNA vaccines: current preclinical and clinical developments and future perspectives.
      ]. Corroborating this data, in humans a phase I trial using gp100 plasmid DNA led several patients to increased levels of gp100-CD8+ T cells [
      • Yuan J.
      • Ku G.Y.
      • Gallardo H.F.
      • Orlandi F.
      • Manukian G.
      • Rasalan T.S.
      • et al.
      Safety and immunogenicity of a humanand mouse gp100 DNA vaccine in a phase I trial of patients with melanoma.
      ]. DNA is more stable than RNA, and its safety makes DNA vaccination an attractive strategy. However, its delivery is more complex than RNA due to its higher dimension and the need for nuclear localization. Improving transfection methods to in vivo delivery is necessary to enhance vaccine efficacy [
      • Rice J.
      • Ottensmeier C.H.
      • Stevenson F.K.
      DNA vaccines: Precision tools for activating effective immunity against cancer.
      ]. Ongoing clinical trials investigating nucleic-acid vaccines are summarized in Table 1.
      Table 1Ongoing clinical trials investigating nucleic acid vaccines in cancer.
      Clinical Trial Identifier CodeInvestigation PlanVaccines, Drug/sClinical Setting Lines of therapyPrimary EndpointStage of DevelopmentClinical Trials Status
      NCT0397074664 participants, Non-Randomized, Sequential Assignment, Open labelPDC*lung01, Keytruda Injectable Product, AlimtaWash out of 4 weeks since last cycle of chemotherapyDLT1/2Recruiting
      NCT02439450121 participants, Non-Randomized, Parallel Assignment, Open labelViagenpumatucel-L, Nivolumab, Pembrolizumab, PemetrexedSecond or laterTEAEs, ORR, PFS1/2Active, not recruiting
      NCT0296023049 participants, Non-Randomized, Parallel Assignment, Open labelK27M peptide, NivolumabSecond lineK27M peptide, Nivolumab1/2Recruiting
      NCT01773395123 participants, Randomized, Parallel Assignment, Triple (Participant, Care Provider, Investigator)GVAX, Busulfan, Fludarabine, Tacrolimus, MethotrexateFirst line18/month PFS2Active, not recruiting

      Peptide-based vaccines

      Antigens must be on the surface and be presented by the Major Histocompatibility Complex I or II (MHC I or II) molecules in order for T cells to recognize them [

      Abbas AK, Lichtman AH, Pillai S. Cellular and molecular immunology - 10th ed.; 2021. p. 600.

      ]. Peptide-based vaccines are specific, safe, and rely heavily on the strong, adaptive immune response to initiate cancer-killing effects [
      • Tay R.E.
      • Richardson E.K.
      • Toh H.C.
      Revisiting the role of CD4+ T cells in cancer immunotherapy—new insights into old paradigms.
      ].
      The peptide-MHC and T cell receptor interactions are highly immunogenic and result in less ‘off-target’ toxicity and central tolerance when neoantigens are targeted. The Synthetic Long Peptide (SLP) vaccines are subunit vaccines made from peptides that mimic epitopes of antigen that trigger direct or potent immune responses. SLPs containing class-I and class-II MHC restricted neoepitopes can induce neoantigen-reactive CD8+ T-cell responses and CD4+ T-cell responses which drive direct antitumor effects. Immunogenicity typically increases with peptides that include multiple epitopes and recognition motifs. This strategy avoids central tolerance and bolsters CD4 and CD8 T cell responses. Short peptides (∼9 aminoacid residues) can be exogenously loaded onto MHC-I molecules of non-professional APCs, leading to a poor T cell response [
      • Slingluff C.L.
      The present and future of peptide vaccines for cancer: Single or multiple, long or short, alone or in combination?.
      ]. Shorter peptides are easily digested by enzymes, and thereby are quickly eliminated in the human blood serum. Longer peptides (25–35 aminoacid residues) are more readily endocytosed by professional APCs, which have the proper machinery to allow complete T cell activation and antigen presentation by MHC-II molecules [
      • Diao L.
      • Meibohm B.
      Pharmacokinetics and pharmacokinetic-pharmacodynamic correlations of therapeutic peptides.
      ]. Short peptides also restrict HLA-type, making broad coverage of HLA-types a greater challenge, thereby making SLP more attractive overall [
      • Southwood S.
      • Sidney J.
      • Kondo A.
      • del Guercio M.F.
      • Appella E.
      • Hoffman S.
      • et al.
      Several common HLA-DR types share largely overlapping peptide binding repertoires.
      ].
      PTHrP plays key roles in a wide variety of solid tumors, including osteosarcoma, breast cancer, lung cancer, chondrosarcoma, anaplastic thyroid cancer, medulloblastoma, adrenocortical tumor, squamous cancer and prostate cancer cell lines. Recently, it has been shown that the combination of anti-PTHrP with zoledronic acid, which is a third-generation bisphosphonate, is promising to control bone-metastasis in immunosuppressed mice depleted of NK cells inoculated with SBC-5 human small cell lung cancer (SCLC) cells, than the agent alone, therefore suggesting that the dual-target therapy is more useful [
      • Luparello C.
      Parathyroid Hormone-Related Protein (PTHrP): A Key Regulator of Life/Death Decisions by Tumor Cells with Potential Clinical Applications.
      ]. The overexpression in cancer cells of Thymidylate Synthase (TS) – a crucial enzyme for DNA repair and replication- inspired the development of a 27-mer peptide vaccine named TS poly-epitope peptide (TSPP) vaccine. TSPP contains three epitopes of HLA-A2.1-binding motifs of TS. The vaccine has shown to be safe and has antitumor activity in both preclinical studies and a clinical (phase 1) investigation [
      • Cusi M.G.
      • Botta C.
      • Pastina P.
      • Rossetti M.G.
      • Dreassi E.
      • Guidelli G.M.
      • et al.
      Phase I trial of thymidylate synthase poly-epitope peptide (TSPP) vaccine in advanced cancer patients.
      ]. To corroborate this data, another phase Ib study of 29 metastatic colorectal cancer showed that the poly-epitope vaccination to TSPP and GOLFIG chemo-immunotherapy was safe and possibly effective [
      • Correale P.
      • Botta C.
      • Martino E.C.
      • Ulivieri C.
      • Battaglia G.
      • Carfagno T.
      • et al.
      Phase Ib study of poly-epitope peptide vaccination to thymidylate synthase (TSPP) and GOLFIG chemo-immunotherapy for treatment of metastatic colorectal cancer patients.
      ].
      Since malignancy-associated hypercalcemia is characterized by excessive production of parathyroid hormone-related protein (PTHrP), a peptide vaccine was developed targeting PTHrP. The first study showed that the vaccine was effective in mice bearing transplanted human PTHrP-producing tumors, as it prolonged their survival [
      • Sato K.
      • Yamakawa Y.
      • Shizume K.
      • Satoh T.
      • Nohtomi K.
      • Demura H.
      • et al.
      Passive immunization with anti-parathyroid hormone-related protein monoclonal antibody markedly prolongs survival time of hypercalcemic nude mice bearing transplanted human PTHrP-producing tumors.
      ]. Interestingly there is a combination of cancer peptides called TAS0313. This cancer vaccine cocktail is made of overall 12 cytotoxic T lymphocyte (CTL) epitope peptides derived from the following eight cancer-associated antigens overexpressed in various types of solid cancers: EGFR, KUA, LCK, MRP3, PTHRP, SART2, SART3, and WHSC2. A Phase I/II study showed that the TAS0313 vaccine could produce an immune response with favorable safety and tolerability in 10 Glioblastoma (GBM) patients [

      Arakawa Y, Okita Y, Narita Y. Efficacy finding cohort of a cancer peptide vaccine, TAS0313, in treating recurrent glioblastoma, vol. 39; 2021. p. 2038-2038. https://doi.org/10.1200/JCO.2021.39.15_SUPPL.2038.

      ]. Generally, improving adaptive immune response, effector functions, and clinical efficacy of SLP vaccines, is an ongoing process at a fast pace.
      Recently, a novel proteogenomic approach has been conducted to identify tumor antigens in colorectal cancer-derived cell lines, with biopsy samples having matched tumors and normal adjacent tissues. In this study, mass spectrometry analyses identified 30,000 unique MHC-I-associated peptides. The authors identified 19 tumor-specific antigens in both microsatellites stable and unstable tumors and intriguingly, 2/3 of them were from non-coding regions. Many of such peptides were from genes involved in colorectal cancer progression. Future vaccine research could use such findings to develop T-cell-based vaccines, in which T cells are primed against these antigens to target and destroy these tumors [
      • Cleyle J.
      • Hardy M.-P.
      • Minati R.
      • Courcelles M.
      • Durette C.
      • Lanoix J.
      • et al.
      Immunopeptidomic analyses of colorectal cancers with and without microsatellite instability.
      ].
      Another recent study investigated multi-epitope-based vaccines for colorectal cancer treatment and prevention. The authors designed various vaccines targeting crucial oncogenes in this cancer, namely DC25B, COX2, RCAS1, and FASCIN1 proteins. Their peptide vaccines targeted human class II MHC for each protein and T-cells specific for both peptides and corresponding recombinant protein. Only when they immunized for both CDC25B and COX2 peptides, they were able to observe a significant tumor growth inhibition in MC38 syngeneic mice vs. control. Therefore, they suggested that immunization with CDC25B and COX2 epitopes could be a good method to suppress tumor development in both treatment and prophylactic models that they were able to evaluate [
      • Corulli L.R.
      • Cecil D.L.
      • Gad E.
      • Koehnlein M.
      • Coveler A.L.
      • Childs J.S.
      • et al.
      Multi-Epitope-Based Vaccines for Colon Cancer Treatment and Prevention.
      ].
      Recently, a study developed a recombinant anti-mKRAS scFV-fused, mutant Hydra actinoporin-like-toxin 1 (mHALT-1) immunotoxin that can recognize and eradicate cells bearing K-Ras antigen from mutated codon-12. They showed high cytotoxic efficacy on SW-480 (bearing the KRASG12V mutation) colorectal cancer cells, whereas they spared NHDF control cells [
      • Mun Teo M.Y.
      • Ceen Ng J.J.
      • Fong J.Y.
      • Hwang J.S.
      • Song A.A.L.
      • Hong Lim R.L.
      • et al.
      Development of a single-chain fragment variable fused-mutant HALT-1 recombinant immunotoxin against G12V mutated KRAS c olorectal cancer cells.
      ].
      A phase II clinical study specifically showed that the combination of chemotherapy with second-line telomerase peptide vaccine (GV1001) in 56 metastatic colorectal cancer patients, was tolerable and modestly effective [
      • Kim S.
      • Kim B.J.
      • Kim I.
      • Kim J.H.
      • Kim H.K.
      • Ryu H.
      • et al.
      A phase II study of chemotherapy in combination with telomerase peptide vaccine (GV1001) as second-line treatment in patients with metastatic colorectal cancer.
      ].
      Viral vaccines can be designed to deliver RNA, which encode peptides antigens that are later displayed by tumor cells and other cells. Also, oncolytic viruses (OVs) are used to selectively infect, replicate in, and lyse malignant cells. In addition to killing infected malignant cells, OVs may promote the destruction of the tumor’s blood cells [
      • Russell S.J.
      • Peng K.-W.
      • Bell J.C.
      Oncolytic virotherapy.
      ]. OVs can act as an effective adjuvant and delivery platform for personalized anticancer vaccines, by using peptide antigens [
      • Roy D.G.
      • Geoffroy K.
      • Marguerie M.
      • Khan S.T.
      • Martin N.T.
      • Kmiecik J.
      • et al.
      Adjuvant oncolytic virotherapy for personalized anti-cancer vaccination.
      ]. One OV therapy that uses an IFN-β-expressing vesicular stomatitis virus (VSV) to treat hepatocellular carcinoma (HCC), recently entered a phase I clinical trial [
      • Pol J.G.
      • Zhang L.
      • Bridle B.W.
      • Stephenson K.B.
      • Rességuier J.
      • Hanson S.
      • et al.
      Maraba Virus as a Potent Oncolytic Vaccine Vector.
      ]. Viral vector vaccines have shown to be a versatile strategy for promoting antitumor activity and will continue to be further developed.
      Vaccines against frameshift mutations have been tested for Lynch tumors and hereditary non-polyposis colorectal cancer (HNPCC). Gebert et al. chose 10 short peptides based on frameshift modifications and immunized C57BL/6 mice, four times biweekly, to confirm the expression of the peptides through an ELISpot immunogenicity assay. In a mouse model for Lynch syndrome (MSH-2 conditional knock-out mice), vaccination improved survival and reduced tumor burden that would otherwise spontaneously develop tumors. These vaccines had to be combined with aspirin and Naproxen (NAP), two nonsteroidal anti-inflammatory drugs used for chemoprevention of HNPCC, to elicit great outcomes in the model [
      • Gebert J.
      • Gelincik O.
      • Oezcan-Wahlbrink M.
      • Marshall J.D.
      • Hernandez-Sanchez A.
      • Urban K.
      • et al.
      Recurrent frameshift neoantigen vaccine elicits protective immunity with reduced tumor burden and improved overall survival in a Lynch syndrome mouse model.
      ]. In glioma models, current cancer vaccines needed anti-programmed death protein-1/ligand1 (PD-1/PD-L1), or anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4), to boost immune response further [
      • Antonios J.P.
      • Soto H.
      • Everson R.G.
      • Orpilla J.
      • Moughon D.
      • Shin N.
      • et al.
      PD-1 blockade enhances the vaccination-induced immune response in glioma.
      ]. Ongoing clinical trials investigating peptide or viral vaccines are summarized in Table 2, Table 3, respectively.
      Table 2Ongoing clinical trials investigating peptide vaccines in cancer.
      Clinical Trial Identifier CodeInvestigation PlanVaccines, Drug/sClinical Setting Lines of therapyPrimary EndpointStage of DevelopmentClinical Trials Status
      NCT0178909918 participants,

      Single Group Assignment,

      Open Label
      UV1 synthetic peptide vaccine and GM-CSFSecond or later linesSafety and tolerability, Immunological response1/2Active, not recruiting
      NCT0178491322 participants,

      Single Group Assignment,

      Open Label
      UV1/hTERT2012PFirst lineSafety and tolerability1/2Active, not recruiting
      NCT03012100280 participants,

      Randomized,

      Parallel Assignment,

      Triple masking,

      Double Blind
      Cyclophosphamide,

      Multi-epitope Folate Receptor Alpha Peptide Vaccine,

      Sargramostim
      Second or later linesDFS2Recruiting
      NCT0172083630 participants,

      Non-Randomized,

      Parallel Assignment,

      Open Label
      Vaccine + PolyICLCSecond or later linesImmunologic response1/2Recruiting
      NCT0019471426 participants,

      Single Group Assignment,

      Open Label
      HER-2/neu Peptide VaccineSecond or later linesImmunologic response,

      AE
      1/2Active, not recruiting
      NCT0360696770 participants,

      Randomized,

      Parallel Assignment,

      Open Label
      Carboplatin,

      Durvalumab,

      Gemcitabine Hydrochloride, Nab-paclitaxel,

      Personalized Synthetic Long Peptide Vaccine, Poly ICLC, Tremelimumab

      First lineClinical response2Recruiting
      NCT0499847415 participants,

      Single Group Assignment,

      Open Label
      FRAME-001 personalized vaccineFourth or later linesFRAME-001-specific immune responses2Not yet recruiting
      NCT0279598836 participants, Randomized,

      Parallel Assignment,

      Partially blinded (outcomes assessor)
      IMU-131, Cisplatin and either Fluorouracil (5-FU) or Capecitabine or Oxaliplatin and capecitabine.First lineSafety and tolerability,

      Recommended Phase 2 dose and clinical efficacy of IMU-131
      1/2Active, not recruiting
      NCT04747002100 participants, Randomized,

      Parallel Assignment,

      Opel label
      DSP-7888Second lineRFS2Recruiting
      NCT0376191490 participants, Non-Randomized,

      Parallel Assignment,

      Opel label
      galinpepimut-S,

      Pembrolizumab
      Second or later linesTRAEs, ORR, CR1/2Active, not recruiting
      NCT02396134133 participants, Randomized,

      Parallel Assignment,

      Triple masking
      CMVpp65-A*0201 peptide vaccineFirst lineCMV reactivation and CD8+ T cells binding2Active, not recruiting
      NCT0263658213 participants, Randomized,

      Parallel Assignment,

      Single masking (Participant)
      Nelipepimut-S Plus GM-CSF Vaccine,

      Sargramostim

      First lineEvaluate CTL2Active, not recruiting
      NCT0512782442 participants, Randomized,

      Factorial Assignment,

      Open label
      Autologous alpha-DC1/TBVA vaccine,

      Cabozantinib
      First lineImmune response,

      Safety
      2Not yet recruiting
      NCT04197687480 participants, Randomized,

      Parallel Assignment,

      Double blinded (participant, care provider)
      Multi-epitope HER2 Peptide Vaccine TPIV100,

      Pertuzumab,

      Sargramostim,

      Trastuzumab,

      Trastuzumab Emtansine
      Second or later linesiDFS2Recruiting
      NCT0524386228 participants, Single Group Assignment,

      Open label
      PolyPEPI1018,

      Atezolizumab
      Third or later linesAEs, Safety2Not yet recruiting
      NCT0212657962 participants, Randomized, Parallel Assignment,

      Open label
      Peptide Vaccine (LPV7) + Tetanus peptide,

      PolyICLC
      Second or later linesSafety and toxicity, T cell response1/2Active, not recruiting
      NCT0070310536 participants, Single Group Assignment,

      Open label
      DC vaccinationSecond or later linesImmune response2Recruiting
      NCT0281842654 participants, Single Group Assignment,

      Open label
      UCPVaxThird or later linesDLT1/2Recruiting
      NCT0304792850 participants, Single Group Assignment,

      Open label
      Nivolumab,

      PD-L1/IDO peptide vaccine
      Second or later linesAEs1/2Recruiting
      NCT0296023049 participants, Non-randomized, Parallel Assignment,

      Open label
      K27M peptide, NivolumabSecond or later linesAEs,

      OS
      1/2Recruiting
      NCT0420625480 participants, Randomized, Parallel Assignment,

      Open label
      gp96Second or later lines2-years RFS2/3Not yet recruiting
      NCT0436423044 participants, Single Group Assignment,

      Open label
      6MHP,

      NeoAg-mBRAF,

      PolyICLC,

      CDX-1140
      First lineSafety of CDX-1140 + melanoma peptide vaccine,

      Immunogenicity
      1/2Recruiting
      NCT0428084828 participants, Single Group Assignment,

      Open label
      UCPVaxSecond or later linesImmunogenicity1/2Active, not recruiting
      NCT0394635847 participants, Single Group Assignment,

      Open label
      Atezolizumab, UCPVaxSecond or later linesORR2Recruiting
      NCT0356075236 participants, Single Group Assignment,

      Open label
      Multi-peptide CMV-Modified Vaccinia Ankara VaccineSecond or later linesAEs2Recruiting
      NCT0405130748 participants, Single Group Assignment,

      Open label
      PD-L1 peptide: PD-L1 Long(19–27), Arginase1 peptide: ArgLong2(169–206)First lineImmune response1/2Recruiting
      NCT0361732830 participants,

      Randomized, Parallel Assignment,

      Open label
      6MHP, Montanide ISA-51, polyICLC, CDX-1127First or second lineSafety and immunogenicity1/2Recruiting
      NCT0188570225 participants,

      Non-Randomized, Parallel Assignment,

      Open label
      DC vaccinationFirst or second lineSafety and feasibility1/2Active, not recruiting
      NCT0280294356 participants,

      Non-Randomized, Parallel Assignment,

      Open label
      Peptide Vaccine, ImiquimodFirst or second lineInduction of peptide-specific T cell responses2Recruiting
      NCT0371598512 participants,

      Sequential Assignment,

      Open label
      EVAX-01-CAF09bSecond or later lineSafety and tolerability1/2Active, not recruiting
      NCT05096481120 participants,

      Single Group Assignment,

      Open label
      PEP-CMV,

      Temozolomide,

      Tetanus Diphtheria Vaccine
      Second linePFS, OS2Not yet recruiting
      NCT0458077135 participants,

      Single Group Assignment,

      Open label
      Cisplatin, Liposomal HPV-16 E6/E7 Multipeptide Vaccine PDS0101, Radiation TherapyFirst lineToxicity2Recruiting
      NCT0245555766 participants,

      Single Group Assignment,

      Open label
      Montanide ISA 51 VG, Sargramostim, SVN53-67/M57-KLH Peptide Vaccine, TemozolomideSecond linePFS

      2Active, not recruiting
      NCT0382127220 participants, Randomized,

      Parallel Assignment,

      Open label
      PepCanSecond lineAEs1/2Recruiting
      NCT0235818725 participants, Randomized,

      Single Group Assignment,

      Open label
      HLA-A2 Restricted Glioma Antigen-Peptides with Poly-ICLCThird lineTumor shrinkage or stable disease2Recruiting
      NCT04114825180 participants, Randomized,

      Parallel Assignment,

      Quadruple masking
      RV001VSecond or later lineTime to PSA progression2Active, not recruiting
      NCT0523285124 participants, Randomized,

      Parallel Assignment,

      Open label
      Liposomal HPV-16 E6/E7 Multipeptide Vaccine PDS0101, PembrolizumabFirst linectHPVDNA response1/2Recruiting
      NCT016975276 participants, Single Group Assignment,

      Open label
      Aldesleukin, fludarabine phosphate, cyclophosphamide, NY-ESO-1 reactive TCR retroviral vector transduced autologous PBL, DC therapy, fludeoxyglucose F 18, PETSecond or later lineClinical response2Active, not recruiting
      NCT03384914110 participants, Randomized Parallel Assignment,

      Open label
      DC1 Vaccine, WOKVAC VaccineSecond or later lineImmunogenicity2Recruiting
      NCT05163080265 participants, Randomized Parallel Assignment,

      Double-Blind
      SurVaxMSecond or later lineOS2Recruiting
      NCT0181481390 participants, Randomized, Parallel Assignment,

      Open label
      HSPPC-96, bevacizumabFirst lineOS2Active, not recruiting
      NCT0491276560 participants, Single Group Assignment,

      Open label
      Neoantigen DC Vaccine, NivolumabSecond or later line24-months Relapse Free Survival2Recruiting
      NCT0363311024 participants, Non-Randomized, Single Group Assignment,

      Open label
      GEN-009 Adjuvanted Vaccine, Nivolumab, PembrolizumabFirst lineAEs, T-cell responses1/2Active, not recruiting
      NCT02506933102 participants, Randomized, Parallel Assignment,

      Double blinded (Participant and Investigator)
      Multi-peptide CMV-Modified Vaccinia Ankara VaccineFirst lineCMV events, Severe AEs2Active, not recruiting
      NCT02134925110 participants, Randomized, Parallel Assignment,

      Double blinded (Participant and Investigator)
      MUC1 Peptide-Poly-ICLC VaccineFirst or second lineChange in Anti-MUC1 Immunoglobulin G (IgG) Levels2Active, not recruiting
      NCT04060277128 participants, Randomized, Parallel Assignment,

      Double blinded (Participant and Care Provider)
      Letermovir, Multi-peptide CMV-Modified Vaccinia Ankara VaccineFirst lineClinically significant cytomegalovirus2Recruiting
      NCT03284866536 participants, Randomized, Parallel Assignment,

      Double blinded (Participant and Investigator)
      Recombinant Human Papillomavirus Nonavalent VaccineSecond or later lineLesions occurrences3Recruiting
      NCT0254374930 participants, Single Group Assignment, Open LabelDC vaccineFirst lineDC toxicity Parameters using CTC1/2Recruiting
      NCT0233473536 participants, Randomized, Parallel Assignment, Open LabelDC Vaccine, Montanide Vaccine, Poly-ICLCFirst lineHumoral immune response2Active, not recruiting
      NCT0444506411 participants, Randomized, Parallel Assignment, Open LabelIO102First lineNumber of participants with a T-cell peptide-specific response to the vaccine2Recruiting
      Table 3Ongoing clinical trials investigating viral vaccines in cancer.
      Clinical Trial Identifier CodeInvestigation PlanViral vaccine/ DrugClinical Setting LinePrimary EndpointStage of DevelopmentClinical Trials Status
      NCT04745377300 participants,

      Observational,

      Case-Control
      SARS-COV-2First lineRate of Covid19 Infection post vaccinationCase-ControlRecruiting
      NCT0441087445 participants,

      Sequential Assignment,

      Open Label
      ImvamuneFirst lineMTD2Recruiting
      NCT0331597540 participants,

      Interventional,

      Single group Assignment,

      Open Label
      Inactivated influenza vaccineFirst lineNeutralizing antibody response4Active, not recruiting
      NCT0452176433 participants,

      Interventional,

      Single group Assignment,

      Open Label
      modified measles virus (MV-s-NAP)Second line or later lineMTD1Recruiting
      NCT038480391220 participants,

      Interventional,

      Randomized Assignment,

      Open Label
      Gardasil-9First lineEvaluation of DRR3Not yet recruiting
      NCT01376505100 participants,

      Non-Randomized,

      Parallel Assignment,

      Open Label
      HER-2 vaccineFirst lineSafety and duration of immune response1Recruiting
      NCT0441090041 participants,

      Non-Randomized,

      Parallel Assignment,

      Open Label
      Wistar Rabies VirusFirst linePositive vaccine response1Recruiting
      NCT0311348728 participants,

      Interventional,

      Single group Assignment,

      Open Label
      Vaccinia Virus expressing p53, PembrolizumabSecond line or later linePFS2Recruiting
      NCT0243296319 participants,

      Interventional,

      Single group Assignment,

      Open Label
      Vaccinia Virus expressing p53, PembrolizumabFirst lineTolerability1Active, not recruiting
      NCT0228581656 participants,

      Non-Randomized,

      Parallel Assignment,

      Open Label
      MG1MA3

      AdMA3
      Second line or later lineMFD2Active, not recruiting
      NCT0343908577 participants, Interventional,

      Single Group Assignment,

      Open Label
      IL-12 DNA plasmids, MEDI0457, DurvalumabFirst lineORR2Active, not recruiting
      NCT04836793300 participants, observational,

      Cohort
      Additional biological samplesFirst lineIgG levels after Covid19 vaccinationRecruiting
      NCT0270023030 participants, Interventional,

      Single Group Assignment,

      Open Label
      Measles Virus Encoding Thyroidal Sodium Iodide SymporterFirst lineDose Response1Recruiting
      NCT0286513511 participants, Interventional,

      Single Group Assignment,

      Open Label
      DPX-E7 vaccineFirst lineSAE2Active, not recruiting
      NCT04355806160 participants, Observational,

      Prospective Assignment,
      PD-1/PD-L1 inhibitors, Inactivated trivalent influenza vaccineFirst lineIgG levelsNot yet recruiting
      NCT04667702330 participants, Observational,

      Prospective Assignment,
      HPVFirst lineVaccine HesitancyRecruiting
      NCT047748871200 participants, Interventional,

      Single group Assignment,

      Open Label
      HPVFirst lineRisk to HPVNot ApplicableNot yet recruiting
      NCT0009253412,167 participants, Interventional,

      Randomized, Single Group Assignment,

      Double Masking
      Gardasil, HPVFirst lineIncidence of Endpoint of HPV3Active, not recruiting
      NCT0297715622 participants, Interventional,

      Single group Assignment,

      Open Label
      Pexa-Vec, IpilimumabFirst lineDLTs, ORR1Active, not recruiting
      NCT0361895375 participants,

      Non-Randomized,

      Parallel Assignment,

      Open Label
      Ad-E6E7

      MG1-E6E7

      Atezolizumab
      First lineSafety1Active, not recruiting
      NCT0356075236 participants, Interventional,

      Single Group Assignment,

      Open Label
      CMV-Modified Vaccinia Ankara VaccineFirst lineSafety2Recruiting
      NCT026531184453 participants, Observational,

      Cohort, Open Label
      V503, GARDASILFirst lineIncidence of HPVActive, not recruiting
      NCT04847050220 participants, Non-Randomized,

      Parallel Assignment, Open Label
      mRNA-1273First lineSafety2Recruiting
      NCT0485498055 participants, Observational,

      Prospective Assignment,
      BloodFirst lineImmune response to vaccineRecruiting
      NCT0458077135 participants, Interventional,

      Single Group Assignment, Open label
      Cisplatin

      Liposomal HPV-16 E6/E7 Multi-peptide Vaccine PDS0101
      First lineRate of grade2Recruiting
      NCT0354799978 participants, Parallel Assignment, Interventional, Randomized, Open LabelmFOLFOX6, MVA-BN-CV301, FPV-CV301, NivolumabFirst lineOS2Active, not recruiting
      NCT02415387180 participants, Crossover Assignment, Interventional, Randomized, Quadrupletyphoid vaccineFirst lineChange in IL6 levelsNot ApplicableRecruiting
      NCT04935528430 participants, Single group Assignment, Interventional, Randomized, Open LabelELISPOT, SerologyFirst lineseroprevalence of SARS-CoV-2Not ApplicableRecruiting
      NCT052379475000 participants, Parallel Assignment, Interventional, Randomized, DoubleDTP, Questionnaire, HPVFirst lineIncidence of persistent HPV infection4Enrolling by invitation
      NCT0264943997 participants, Parallel Assignment, Interventional, Randomized, Open LabelPROSTVAC –V, PROSTVAC-FFirst lineTumor growth rate2



      Active, not recruiting
      NCT0186733357 participants, Parallel Assignment, Interventional, Randomized, Open LabelPROSTVAC-F/TRICOM

      PROSTVAC-V/TRICOM, Enzalutamide (Xtandi)
      First lineIncrease in time to progression2Active, not recruiting
      NCT0507886645 participants, Single group Assignment, Interventional, Randomized, Open LabelGAd-209-FSP, MVA-209-FSPFirst lineAdverse events2Not yet recruiting
      NCT0404131084 participants, Sequential Assignment, Interventional, Non-RandomizedGAd-209-FSP, MVA-209-FSPFirst lineToxicity2Recruiting
      NCT04977024240 participants, Parallel Assignment, Interventional, Triple maskingCOVID-19 VaccineFirst linebiological activity2Recruiting
      NCT0200218215 participants, Non-randomized Parallel Assignment, Interventional, Open LabelADXS11-001 (ADXS-HPV)First lineHPV-Specific T Cell Response Rate2Active, not recruiting
      NCT04442048195 participants, Randomized Parallel Assignment, Interventional, Open LabelIMM-101First linerate of “flu-like illness”3Active, not recruiting
      NCT0360380880 participants, Single group Assignment, Interventional, Randomized, Open LabelHPV DNA Plasmids (VGX-3100)First lineORR2Recruiting
      NCT051733248000 participants,

      Randomized,

      Parallel Assignment,

      Quadruple
      HPV vaccine HAV vaccineFirst lineHPV prevalent infections3Not yet recruiting
      NCT03350698100 participants,

      Randomized,

      Single group Assignment,

      Open label
      Gardasil-9First linePrevention4Recruiting
      NCT046354231050 participants,

      Randomized,

      Parallel Assignment,

      Triple
      V503First lineCombined incidence of HPV 6/11/16/18-related anogenital persistent infection3Active, not recruiting
      NCT04274153130 participants,

      Single group Assignment,

      Interventional,

      Open label
      Gardasil9First lineImmunogenicity of HPV vaccine4Recruiting
      NCT02834637930 participants, Parallel Assignment, Interventional, Randomized, Open Labelbivalent HPV vaccine, nonavalent HPV vaccineFirst lineProportion with HPV 16/18-specific seropositivity3Active, not recruiting
      NCT03284866536 participants, Parallel Assignment, Interventional, Randomized, DoubleGardasil 9First lineOccurrence of cervical cancer3Recruiting
      NCT0264985574 participants, Parallel Assignment, Interventional, Randomized, Open LabelPROSTVAC-V, PROSTVAC-F, DocetaxelFirst lineResponse/efficacy2Active, not recruiting
      NCT0331587134 participants, Parallel Assignment, Interventional, Non-Randomized, Open LabelPROSTVAC-V, PROSTVAC-F, MSB0011359CFirst lineResponse of combination immunotherapy2Recruiting
      NCT02396134133 participants, Parallel Assignment, Interventional, Non-Randomized, Triple maskingCMVpp65-A*0201 peptide vaccineFirst linenon-relapse mortality2Active, not recruiting
      NCT05266898150 participants, Single group Assignment, Interventional, Open LabelHuman papillomavirus 9-valent vaccineFirst linechange in serological response to Gardasil-94Not yet recruiting
      NCT018245371000 participants, Randomized, Factorial Assignment, Interventional, QuadrupleGardasil 9, Hepatitis A vaccineFirst lineReduction in HPV type concordance4Recruiting
      NCT04534205285 participants, Randomized, Parallel Assignment, Interventional, Open LabelBNT113, PembrolizumabFirst lineTEAE and ORR2Recruiting
      NCT04060277128 participants, Randomized, Parallel Assignment, Interventional, Open LabelLetermovir, Multi-peptide CMV-Modified Vaccinia Ankara VaccineFirst lineNon-relapse mortality2Recruiting



      NCT03702231116 participants, Non-Randomized, Parallel Assignment, Interventional, Open LabelZoster Vaccine Recombinant, AdjuvantedFirst lineSafety and Tolerability2Active, not recruiting
      NCT04484532200 participants, Single group Assignment, Interventional, Open LabelTrivalent Influenza VaccineSecond or later lineAntibody response4Recruiting
      NCT0318003425,000 participants, Randomized, Parallel Assignment, Interventional, DoubleDTP adsorbed, HPV bivalent, HPV NonavalentSecond or later lineIncidence of persistent human papillomavirus (HPV)-16 or 18 cervical infections4Active, not recruiting
      NCT0083409318 participants, Single group Assignment, Interventional, Open LabelEpstein-Barr Virus Specific ImmunotherapyFirst lineORR2Active, not recruiting
      NCT037288811240 participants, Non-Randomized, Parallel Assignment, Interventional, Open LabelQuadrivalent HPV virus, bivalent HPV vaccineFirst lineAntibody levels of HPV163Active, not recruiting
      NCT02506933102 participants, Randomized, Parallel Assignment, Double maskingMulti-peptide CMV-Modified Vaccinia Ankara VaccineFirst lineCMV events encompassing any CMV reactivation2Active, not recruiting

      NCT0404644596 participants, Non-Randomized, Parallel Assignment, Interventional, Open LabelATP128, BI 754091, VSV-GP128First linesafety and tolerability and SAEs2Recruiting
      NCT02481414125 participants, Randomized, Parallel Assignment, Interventional, Open LabelPepCan, CandinSecond or later lineEfficacy2Active, not recruiting
      NCT03391921170 participants, Randomized, Parallel Assignment, Interventional, Open LabelVaccineSecond or later lineRate of seroconversion in HPV antibodies against HPV4Active, not recruiting
      NCT0526201013,500 participants, Randomized, Parallel Assignment, Interventional, Open Label11-valent recombinant human papilloma virus vaccineFirst linePerson-years incidence of CIN2 + associated with HPV6/11/16/183Not yet recruiting
      NCT04436133480 participants, Randomized, Parallel Assignment, Interventional, Double11-valent recombinant human papilloma virus vaccine, Gardasil 9First lineAnti-HPV neutralizing antibodies GMT2Active, not recruiting
      NCT03943875512 participants, Randomized, Parallel Assignment, Interventional, Open Label9-valent HPV vaccineFirst lineEfficacy4Recruiting
      NCT0448293330 participants, single group Assignment, Interventional, Open LabelBiological G207Second line or later lineEfficacy2Not yet recruiting
      NCT041996896000 participants, Randomized, Parallel Assignment, Interventional, Triple masking9vHPV VaccineSecond line or later lineIncidence of HPV3Active, not recruiting
      NCT039035621990 participants, Randomized, Single group Assignment, Interventional, Open LabelV503First lineSerum antibody titers for HPV3Active, not recruiting
      NCT0495313010,400 participants, Randomized, Parallel Assignment, Interventional, Open LabelGardasil HPV vaccineFirst lineImpact of HPV vaccination4Not yet recruiting
      NCT04951323anti-COVID19 mRNA-based vaccineanti-COVID19 mRNA-based vaccine (BNT162b2)First lineQuantification of anti-SARS-CoV-2 receptor binding domain specific IgG3Recruiting
      NCT0275020275 participants, Randomized, Parallel Assignment, Interventional, single maskingQuadrivalent HPV vaccine, Hepatitis B vaccineFirst lineChange in the genital wart lesion3Recruiting
      NCT0529184575 participants, Randomized, Factorial Assignment, Interventional, open labelCandida antigen vaccine, Bivalent HPV vaccineSecond line or later linecomplete response2Not yet recruiting
      NCT050277761348 participants, Randomized, Parallel Assignment, Interventional, open labelHPV vaccineFirst linePrimary immunogenicity3Recruiting
      NCT04708041700 participants, Randomized, Parallel Assignment, Interventional, open label9vHPV vaccineFirst lineGMT of HPV3Active, not recruiting
      NCT04474821300 participants, Randomized, Single group Assignment, Interventional, open labelHuman Papillomavirus InfectionSecond line or later lineAcceptance and completion rates of free HPV vaccination4Recruiting
      NCT048950201200 participants, Single group Assignment, Interventional, open label9-valent HPV vaccineFirst lineprimary immunogenicity3Recruiting
      NCT044223668000 participants, Parallel group Assignment, Interventional, open label9-valent Human Papillomavirus, GARDASILFirst lineperson-year incidence of HPV3Recruiting
      NCT039982546000 participants, Parallel group Assignment, Interventional, double labelV503, GardasilSecond line or later lineCombined Incidence of HPV related 12-month Persistent Infection3Active, not recruiting
      NCT052858268100 participants, Parallel group Assignment, Interventional, double label9vHPV vaccineFirst lineCombined Incidence of HPV 58-related External Genital and Intra-anal 12-month Persistent Infection3Recruiting
      NCT05279248300 participants, Parallel Assignment, Interventional, Open labelHPV + MMR,HPVFirst lineGMT of anti-HPV 16 and 18 at 7 months4Active, not recruiting
      NCT048703335000 participants, Parallel Assignment, Randomized,

      Interventional, Open label
      Niclosamide, Ciclesonide, SotrovimabFirst linePrevention3Recruiting
      NCT05119855400 participants, Parallel Assignment, Randomized,

      Interventional, Open label
      9vHPV Vaccine, mRNA-1273 VaccineFirst lineGMT of HPV3Recruiting

      Cellular vaccines

      In DC-vaccine development, DCs are loaded with tumor antigens in the forms of mRNAs, proteins, peptides, or tumor lysates [
      • Le D.T.
      • Pardoll D.M.
      • Jaffee E.M.
      Cellular vaccine approaches.
      ]. Normally, antigen delivery to the DCs occurs ex-vivo, where they are activated and reinjected. However, this process may impair dendritic cell trafficking to secondary lymphoid organs. An alternative strategy is to infect patient DCs with viral vectors encoding desired antigens or fuse their DCs with tumor cells [
      • Yamamoto L.
      • Amodio N.
      • Gulla A.
      • Anderson K.C.
      Harnessing the Immune System Against Multiple Myeloma: Challenges and Opportunities.
      ]. Further investigation is required to standardize an effective DC-based vaccine engineering.
      Another type of cellular vaccine is created using irradiated allogeneic whole tumor cells or autologous patient-derived tumor cells to induce antitumor immune responses [
      • Keenan B.P.
      • Jaffee E.M.
      Whole cell vaccines - Past progress and future strategies.
      ]. To enhance immune response against whole tumor cells, new generations of tumor cell vaccines have been genetically modified to either produce co-stimulatory molecules, chemokines, cytokines, or reduce inhibitory molecule production [
      • Chiang C.L.-L.
      • Coukos G.
      • Kandalaft L.E.
      Whole Tumor Antigen Vaccines: Where Are We?.
      ]. For example, the FANG vaccine contains autologous-tumor cells modified with a plasmid that encodes a bi-functional short hairpin RNAi that targets furin convertase resulting in downregulation of TGF-β, an immunosuppressive transforming growth factor [
      • Senzer N.
      • Barve M.
      • Kuhn J.
      • Melnyk A.
      • Beitsch P.
      • Lazar M.
      • et al.
      Phase I Trial of “bi-shRNAifurin/GMCSF DNA/Autologous Tumor Cell” Vaccine (FANG) in Advanced Cancer.
      ]. After tumor cells or lysate is delivered, DCs initiate T cell activation by cross-priming CD8+ T cells [
      • Chiang C.L.-L.
      • Coukos G.
      • Kandalaft L.E.
      Whole Tumor Antigen Vaccines: Where Are We?.
      ]. This strategy allows multiple tumor antigens to be targeted simultaneously without neoantigen identification prior to administration. However, neoantigen mutational burden and quality are still considered to be associated with good prognosis and are good predictors of treatment success. One study showed that neoantigen vaccine effectiveness was limited by a low mutational burden [
      • Martin S.D.
      • Brown S.D.
      • Wick D.A.
      • Nielsen J.S.
      • Kroeger D.R.
      • Twumasi-Boateng K.
      • et al.
      Low Mutation Burden in Ovarian Cancer May Limit the Utility of Neoantigen-Targeted Vaccines.
      ]. Even checkpoint inhibitor antibodies targeting PD-1 and CTLA-4 have improved clinical response when tumors have a higher mutation frequency [
      • Rizvi N.A.
      • Hellmann M.D.
      • Snyder A.
      • Kvistborg P.
      • Makarov V.
      • Havel J.J.
      • et al.
      Mutational landscape determines sensitivity to PD-1 blockade in non-small cell lung cancer.
      ,
      • Snyder A.
      • Makarov V.
      • Merghoub T.
      • Yuan J.
      • Zaretsky J.M.
      • Desrichard A.
      • et al.
      Genetic Basis for Clinical Response to CTLA-4 Blockade in Melanoma.
      ]. Salewski et al. showed mice administered with autologous-cell line-derived tumor lysates from 328 and A7450 T1 M1 cell lines, with high-quality neoantigens, are more effective at promoting a prophylactic effect on gastrointestinal tumor formation [
      • Salewski I.
      • Gladbach Y.S.
      • Kuntoff S.
      • Irmscher N.
      • Hahn O.
      • Junghanss C.
      • et al.
      In vivo vaccination with cell line-derived whole tumor lysates: neoantigen quality, not quantity matters.
      ]. Therefore, neoantigen identification may still add some value to tumor cell vaccine design. Regardless, improvements will need to be made to further enhance antitumor response associated with cellular vaccines.

      From sequence mutations to the identification of neoantigens for vaccines

      Neoantigens identification depends on several fundamental factors besides somatic mutations: translation, post-translational modifications and affinity between mutated peptide and patients’ MHC molecules, and affinity between mutant peptide-MHC complex with T-cell receptor (TCR) [
      • Schumacher T.N.
      • Schreiber R.D.
      Neoantigens in cancer immunotherapy.
      ]. Prediction of neoantigens needs to combine both genomic mutations and MHC information on patients, and different software has shown this conjunction to be useful, as summarized in Table 4 [
      • Yadav M.
      • Jhunjhunwala S.
      • Phung Q.T.
      • Lupardus P.
      • Tanguay J.
      • Bumbaca S.
      • et al.
      Predicting immunogenic tumour mutations by combining mass spectrometry and exome sequencing.
      ,
      • Sahin U.
      • Derhovanessian E.
      • Miller M.
      • Kloke B.P.
      • Simon P.
      • Löwer M.
      • et al.
      Personalized RNA mutanome vaccines mobilize poly-specific therapeutic immunity against cancer.
      ,
      • Ott P.A.
      • Hu Z.
      • Keskin D.B.
      • Shukla S.A.
      • Sun J.
      • Bozym D.J.
      • et al.
      An immunogenic personal neoantigen vaccine for patients with melanoma.
      ,
      • Gubin M.M.
      • Zhang X.
      • Schuster H.
      • Caron E.
      • Ward J.P.
      • Noguchi T.
      • et al.
      Checkpoint blockade cancer immunotherapy targets tumour-specific mutant antigens.
      ].
      Table 4Neoantigen prediction softwares.
      Software (references)PrincipleYear
      NeoPredPipe [140]Connects commonly used bioinformatics software using custom python scripts giving neoantigen burden, immune stimulation potential, tumor heterogeneity and HLA haplotype of patients.2019
      Strelka2 [141]Estimates error or deletion parameters of each sample improved tumor liquid analysis2018
      MuPeXI [142]Identifies tumor-specific peptides through the extraction and induction of mutant peptides, it can predict immunogenicity and evaluate the potential of novel peptides2017
      CloudNeo pipeline [143]The docker container executes the tasks. After giving as an input mutant VCF file and bam FILE representing HLA typing, the software predicts HLA affinity all mutant peptides.2017
      pVAC-Seq [144]Integrates tumor mutation and expression data to identify personalized mutagens through personalized sequencing.2016
      NetMHCpan [145]The sequences are compared using artificial intelligence neural network and predict affinity of molecular peptide-MHC-I type2016
      VariantEffect Predictor Tool [146]It uses automated annotations to manual review time and prioritize variants2016
      Somaticseq [147]It uses a randomized enhancement algorithm, which has more than 70 individual genome sequence features based on candidate sites to accurately detect somatic mutations2015
      OptiType [148]It uses an HLA type algorithm with a linear programming that gives sequencing databases comprising RNA, exome and whole genome sequencings.2014
      ATHLATES [149]It assembles allele recognition, pair interface applied to short sequences and HLA genotyping at allele level achieved via exon sequencing2013
      VarScan2 [150]It detects somatic and copy number mutations within tumor-normal exome data using a heuristic statistical algorithm.2012
      HLAminer [151]Through a shotgun sequencing Illumina database platform, predicts HLA type through an orientation of the assembly of the shotgun sequence data to then compare it with databases of allele sequences used as references.2012
      Strelka [152]It uses a Bayesian model that matches normal-tumor sample sequencing data to analyze and predict with high accuracy and sensitivity somatic cellular variations2012
      SMMPMBEC [153]Through a Beyesian matrix based on optimal neural network they can predict peptide molecules with MHC-I2009
      UCSC browser [154]The fusion of various databases can give fast and accurate access to any gene sequence.2002

      Discovery of personalized neoantigens from patients

      Next-generation sequencing has advanced cancer therapy to allow patients to receive personalized therapies such as cancer vaccine, to generate a robust immune response against a patient’s cancer cells based on their unique molecular profile.
      Existing immunotherapies reactivating the immune system work for only 30% of patients [
      • Wei S.C.
      • Duffy C.R.
      • Allison J.P.
      Fundamental mechanisms of immune checkpoint blockade therapy.
      ]. Hence, other ways to boost antitumor immune response using a targeted vaccine for specific patient genetics and MHCs, are urgently needed [
      • Campbell P.J.
      • Pleasance E.D.
      • Stephens P.J.
      • Dicks E.
      • Rance R.
      • Goodhead I.
      • et al.
      Subclonal phylogenetic structures in cancer revealed by ultra-deep sequencing.
      ,
      • Alexandrov L.B.
      • Nik-Zainal S.
      • Wedge D.C.
      • Aparicio S.A.J.R.
      • Behjati S.
      • Biankin A.V.
      • et al.
      Signatures of mutational processes in human cancer.
      ,
      • Lawrence M.S.
      • Stojanov P.
      • Polak P.
      • Kryukov G.V.
      • Cibulskis K.
      • Sivachenko A.
      • et al.
      Mutational heterogeneity in cancer and the search for new cancer-associated genes.
      ,
      • Vogelstein B.
      • Papadopoulos N.
      • Velculescu V.E.
      • Zhou S.
      • Diaz L.A.
      • Kinzler K.W.
      Cancer genome landscapes.
      ]. Additionally, tumors expressing more neoantigens are associated with a stronger immune response and better survival [
      • Rooney M.S.
      • Shukla S.A.
      • Wu C.J.
      • Getz G.
      • Hacohen N.
      Molecular and genetic properties of tumors associated with local immune cytolytic activity.
      ,
      • Brown S.D.
      • Warren R.L.
      • Gibb E.A.
      • Martin S.D.
      • Spinelli J.J.
      • Nelson B.H.
      • et al.
      Neo-antigens predicted by tumor genome meta-analysis correlate with increased patient survival.
      ,
      • Giannakis M.
      • Mu X.J.
      • Shukla S.A.
      • Qian Z.R.
      • Cohen O.
      • Nishihara R.
      • et al.
      Genomic Correlates of Immune-Cell Infiltrates in Colorectal Carcinoma.
      ]. Therefore, harnessing the natural ability of the immune system to detect and kill cancer cells [
      • Hu Z.
      • Ott P.A.
      • Wu C.J.
      Towards personalized, tumour-specific, therapeutic vaccines for cancer.
      ].

      Creating neoantigen-based vaccines

      Due to the application of NGS, discovering tumor neoantigens has become a valuable tool for developing a personalized neoantigen vaccine. To manufacture a neoantigen vaccine, it is essential to compare patients’ tumor cells to their normal cells using whole-exome sequencing to identify mutations uniquely present in tumor cells [
      • Hu Z.
      • Ott P.A.
      • Wu C.J.
      Towards personalized, tumour-specific, therapeutic vaccines for cancer.
      ]. Neoantigens are made from mutated proteins from DNA mutations. However, not all DNA mutations are missense or nonsense to produce mutated proteins. Techniques such as RNA-seq can be used to discriminate those mutations that lead to the formation of neoantigens to target vaccines. Secondly, only some peptides from processed mutated proteins can bind to HLA class I molecules. Neural network-based algorithms were used to predict which mutant proteins are most likely to undergo this transformation, and be presented on the surface of tumor cells or APCs as neoantigens [
      • Rooney M.S.
      • Shukla S.A.
      • Wu C.J.
      • Getz G.
      • Hacohen N.
      Molecular and genetic properties of tumors associated with local immune cytolytic activity.
      ,
      • Fritsch E.F.
      • Rajasagi M.
      • Ott P.A.
      • Brusic V.
      • Hacohen N.
      • Wu C.J.
      HLA-Binding Properties of Tumor Neoepitopes in Humans.
      ,
      • Rajasagi M.
      • Shukla S.A.
      • Fritsch E.F.
      • Keskin D.B.
      • DeLuca D.
      • Carmona E.
      • et al.
      Systematic identification of personal tumor-specific neoantigens in chronic lymphocytic leukemia.
      ]. These neoantigens are most likely to be detected by T cells to produce a strong tumor-specific immune response. The number of neoantigens included in a vaccine varies by patient, but, so far, up to 20 different neoantigens have been included in a single personalized vaccine [
      • Mun Teo M.Y.
      • Ceen Ng J.J.
      • Fong J.Y.
      • Hwang J.S.
      • Song A.A.L.
      • Hong Lim R.L.
      • et al.
      Development of a single-chain fragment variable fused-mutant HALT-1 recombinant immunotoxin against G12V mutated KRAS c olorectal cancer cells.
      ] (Fig. 2).
      Figure thumbnail gr2
      Fig. 2Identification of neoantigens: Tumor-specific mutations are identified using whole-exome sequencing (WES), confirmed by RNA sequencing, then ranked by predicted affinity binding to HLA types; finally, neoantigens are synthesized based on mutated alleles followed by ex vivo T-cell reactivity analysis to confirm the immunogenicity.

      Neoantigen vaccines stimulate tumor-specific T cells

      Clinical trials of personalized cancer vaccines in solid tumors have shown that neoantigen vaccines can generate tumor-specific T cells that only recognize the tumor without serious side effects [
      • Wei S.C.
      • Duffy C.R.
      • Allison J.P.
      Fundamental mechanisms of immune checkpoint blockade therapy.
      ,
      • Sonntag K.
      • Hashimoto H.
      • Eyrich M.
      • Menzel M.
      • Schubach M.
      • Döcker D.
      • et al.
      Immune monitoring and TCR sequencing of CD4 T cells in a long term responsive patient with metastasized pancreatic ductal carcinoma treated with individualized, neoepitope-derived multipeptide vaccines: a case report.
      ,
      • Keskin D.B.
      • Anandappa A.J.
      • Sun J.
      • Tirosh I.
      • Mathewson N.D.
      • Li S.
      • et al.
      Neoantigen vaccine generates intratumoral T cell responses in phase Ib glioblastoma trial.
      ,
      • Hilf N.
      • Kuttruff-Coqui S.
      • Frenzel K.
      • Bukur V.
      • Stevanović S.
      • Gouttefangeas C.
      • et al.
      Actively personalized vaccination trial for newly diagnosed glioblastoma.
      ,
      • Johanns T.M.
      • Miller C.A.
      • Liu C.J.
      • Perrin R.J.
      • Bender D.
      • Kobayashi D.K.
      • et al.
      Detection of neoantigen-specific T cells following a personalized vaccine in a patient with glioblastoma.
      ]. Recent glioblastoma clinical trials have revealed that peripheral stimulation by vaccine-generated T-cells with neoantigen specificity could be tracked inside the tumor [
      • Keskin D.B.
      • Anandappa A.J.
      • Sun J.
      • Tirosh I.
      • Mathewson N.D.
      • Li S.
      • et al.
      Neoantigen vaccine generates intratumoral T cell responses in phase Ib glioblastoma trial.
      ]. To overcome immune resistance, many current clinical trials have combined personalized vaccines with immunotherapies. For example, Roche has started a clinical trial combining a personalized neoantigen vaccine with PD-L1 therapy to treat melanoma and non-small cell lung cancer [

      A Study of Autogene Cevumeran (RO7198457) as a Single Agent and in Combination With Atezolizumab in Participants With Locally Advanced or Metastatic Tumors - Full Text View - ClinicalTrials.gov; n.d.

      ]. Neoantigens predicting algorithms like HLA-thena, have improved based on mass spectrometry data and can better predict HLA-binding preferences for various types of patients [
      • Sarkizova S.
      • Klaeger S.
      • Le P.M.
      • Li L.W.
      • Oliveira G.
      • Keshishian H.
      • et al.
      A large peptidome dataset improves HLA class I epitope prediction across most of the human population.
      ].
      Although current research mainly focuses on HLA class-I molecule to generate T cells that kill cancer cells, research on class II HLA to induce memory T cells, had been conducted to induce a long-lasting response.
      Currently, not all neoantigens in a vaccine produce T cell response, as neoantigens must bind to HLA class I molecules (on the surface of cancer cells), or to class II (on the surface of APCs), as well as to T cell receptors (TCRs) [
      • Sarkizova S.
      • Klaeger S.
      • Le P.M.
      • Li L.W.
      • Oliveira G.
      • Keshishian H.
      • et al.
      A large peptidome dataset improves HLA class I epitope prediction across most of the human population.
      ]. There are still several opportunities to improve the selection of neoantigen to elicit the best antitumor response.
      As NGS and predictive algorithms continue to advance, personalized cancer vaccines will continue to impact the field of immunotherapy. The rationale is to act against cancer cells by promoting immunity by vaccines and removing suppression immunity by inhibitor drugs, besides conventional chemotherapies.

      Cancer vaccines targeting immune checkpoint proteins

      Immunotherapy has significantly revolutionized cancer therapy by using monoclonal antibodies targeted to immune checkpoint molecules that are very active, even in advanced stages of the disease [
      • Chen J.
      • Liu H.
      • Jehng T.
      • Li Y.
      • Chen Z.
      • Lee K.D.
      • et al.
      A Novel Anti-PD-L1 Vaccine for Cancer Immunotherapy and Immunoprevention.
      ,
      • Kaumaya P.T.P.
      • Guo L.
      • Overholser J.
      • Penichet M.L.
      • Bekaii-Saab T.
      Immunogenicity and antitumor efficacy of a novel human PD-1 B-cell vaccine (PD1-Vaxx) and combination immunotherapy with dual trastuzumab/pertuzumab-like HER-2 B-cell epitope vaccines (B-Vaxx) in a syngeneic mouse model.
      ,
      • Thompson E.A.
      • Liang F.
      • Lindgren G.
      • Sandgren K.J.
      • Quinn K.M.
      • Darrah P.A.
      • et al.
      Human Anti-CD40 Antibody and Poly IC:LC Adjuvant Combination Induces Potent T Cell Responses in the Lung of Nonhuman Primates.
      ,
      • Melssen M.M.
      • Petroni G.R.
      • Chianese-Bullock K.A.
      • Wages N.A.
      • Grosh W.W.
      • Varhegyi N.
      • et al.
      A multipeptide vaccine plus toll-like receptor agonists LPS or polyICLC in combination with incomplete Freund’s adjuvant in melanoma patients.
      ,
      • Pockros P.J.
      • Guyader D.
      • Patton H.
      • Tong M.J.
      • Wright T.
      • McHutchison J.G.
      • et al.
      Oral resiquimod in chronic HCV infection: Safety and efficacy in 2 placebo-controlled, double-blind phase IIa studies.
      ,
      • Kasturi S.P.
      • Skountzou I.
      • Albrecht R.A.
      • Koutsonanos D.
      • Hua T.
      • Nakaya H.I.
      • et al.
      Programming the magnitude and persistence of antibody responses with innate immunity.
      ,
      • Lynn G.M.
      • Laga R.
      • Darrah P.A.
      • Ishizuka A.S.
      • Balaci A.J.
      • Dulcey A.E.
      • et al.
      In vivo characterization of the physicochemical properties of polymer-linked TLR agonists that enhance vaccine immunogenicity.
      ]. These results led to the study of peptide vaccines capable of generating antibodies against immune checkpoint proteins in the body.
      PD-L1-based vaccine made from the fusion of extracellular domain of PD-L1 (PD-L1E) to C-terminal region of translocation domain of diphtheria toxin (DTT), showed to elicit CD4+ T cell response inducing Th1 antitumor immunity in mouse tumor models. In this study, PD-L1E was extracted from sera, blocked the binding of PD-L1 to PD-1 in vitro, which revealed a specific interaction. Moreover, PD-L1E vaccination induced an increase in TILs levels and a decrease in LAG3 + PD-1 + levels and CD8+ T cells. The data suggest that the PD-L1 vaccine reverses tumor suppression and could be a promising strategy for cancer therapy [
      • Lin Z.
      • Zhang Y.
      • Cai H.
      • Zhou F.
      • Gao H.
      • Deng L.
      • et al.
      A PD-L1-based cancer vaccine elicits antitumor immunity in a mouse melanoma model.
      ].
      Another strategy consists of DCs loaded with an immunogenic PD-L1 (PD-L1-Vax), which has been shown to induce anti-PD-L1 immune responses and tumor inhibition in cancer cells expressing PD-L1 [
      • Chen J.
      • Liu H.
      • Jehng T.
      • Li Y.
      • Chen Z.
      • Lee K.D.
      • et al.
      A Novel Anti-PD-L1 Vaccine for Cancer Immunotherapy and Immunoprevention.
      ].
      Kaumaya et al. recently developed a novel chimeric B-cell peptide epitope capable of targeting PD-1 linked to measles fusion protein (MVF, sequence 288–302) T-cell epitope, that could elicit polyclonal antibodies in the body, enabling blockage of PD-1 signaling, and mimicking the effects of nivolumab. The authors observed that their vaccine candidate with epitope sequence 92–110 (PD-1-Vax), significantly reduced tumor growth in the syngeneic BALB/c CT26 mouse model [
      • Kaumaya P.T.P.
      • Guo L.
      • Overholser J.
      • Penichet M.L.
      • Bekaii-Saab T.
      Immunogenicity and antitumor efficacy of a novel human PD-1 B-cell vaccine (PD1-Vaxx) and combination immunotherapy with dual trastuzumab/pertuzumab-like HER-2 B-cell epitope vaccines (B-Vaxx) in a syngeneic mouse model.
      ].

      Neoantigen vaccines potentiating the immune response

      Although neoantigens vaccines have been extensively studied for personalized immunotherapy, the vast majority of neoantigens have very minimal to no immunogenicity. An important role is played by adjuvants, because they can elicit a powerful immune response. Among other approaches that can potentiate immunogenicity of neoantigens to develop powerful and durable cancer response, there are: synergistic modulation of multiple immune signaling pathways, presence of multiepitope antigens that elicit a broad spectrum of immune responses, and cancer-specific antigens capable of inducing a specific adaptive immune response.
      Currently, adjuvants such as polyinosinic-polycytidylic acid-poly-L-Lysine carboxy methyl cellulose (poly-ICLC) in combination with anti-CD40 have been used in neoantigen vaccines. However, not all adjuvants can induce a robust immune response, and some soluble vaccine formulations may also limit the immunogenicity of the vaccine itself [
      • Thompson E.A.
      • Liang F.
      • Lindgren G.
      • Sandgren K.J.
      • Quinn K.M.
      • Darrah P.A.
      • et al.
      Human Anti-CD40 Antibody and Poly IC:LC Adjuvant Combination Induces Potent T Cell Responses in the Lung of Nonhuman Primates.
      ,
      • Melssen M.M.
      • Petroni G.R.
      • Chianese-Bullock K.A.
      • Wages N.A.
      • Grosh W.W.
      • Varhegyi N.
      • et al.
      A multipeptide vaccine plus toll-like receptor agonists LPS or polyICLC in combination with incomplete Freund’s adjuvant in melanoma patients.
      ]. To overcome these challenges, pathogen-imitating nanovaccines were created and seem to have a great potential in improving the immunogenicity of neoantigens for cancer immunotherapy. Due to their small size (5–100 nm), nanovaccines can be effectively delivered to secondary lymphoid tissues like lymph nodes and APCs, where they can be retained for a long time. Delivering neoantigens with multiple synergistic adjuvants into lymph nodes [106-109] or APCs [
      • Pockros P.J.
      • Guyader D.
      • Patton H.
      • Tong M.J.
      • Wright T.
      • McHutchison J.G.
      • et al.
      Oral resiquimod in chronic HCV infection: Safety and efficacy in 2 placebo-controlled, double-blind phase IIa studies.
      ,
      • Kasturi S.P.
      • Skountzou I.
      • Albrecht R.A.
      • Koutsonanos D.
      • Hua T.
      • Nakaya H.I.
      • et al.
      Programming the magnitude and persistence of antibody responses with innate immunity.
      ,
      • Lynn G.M.
      • Laga R.
      • Darrah P.A.
      • Ishizuka A.S.
      • Balaci A.J.
      • Dulcey A.E.
      • et al.
      In vivo characterization of the physicochemical properties of polymer-linked TLR agonists that enhance vaccine immunogenicity.
      ] is an essential step for ideal immunotherapy.
      The administration through encapsulation of adjuvants and neoantigens can improve the pharmacokinetic properties of drug payloads, further enhancing immunomodulation. Recently, bi-adjuvant neoantigen nanovaccines (banNVs) co-delivered a peptide neoantigen with two adjuvants, TLR7/8 agonist R848, and TLR9 agonist CpG oligos, were developed to enhance immunogenicity. The combination of banNVs together anti-PD-1-induced potent and durable cancer immunotherapy when combined with anti-PD-1 [
      • Ni Q.
      • Zhang F.
      • Liu Y.
      • Wang Z.
      • Yu G.
      • Liang B.
      • et al.
      A bi-adjuvant nanovaccine that potentiates immunogenicity of neoantigen for combination immunotherapy of colorectal cancer.
      ]. TLR7/8 agonists used for cancer treatment in clinics [
      • Ni Q.
      • Zhang F.
      • Liu Y.
      • Wang Z.
      • Yu G.
      • Liang B.
      • et al.
      A bi-adjuvant nanovaccine that potentiates immunogenicity of neoantigen for combination immunotherapy of colorectal cancer.
      ], especially imiquimod and resiquimod (R848) are US FDA-approved drugs to treat topical skin lesions. The combination of these immune adjuvants exhibited synergistic therapeutic efficacy through the TLR-Myd88 pathway [
      • Ni Q.
      • Zhang F.
      • Liu Y.
      • Wang Z.
      • Yu G.
      • Liang B.
      • et al.
      A bi-adjuvant nanovaccine that potentiates immunogenicity of neoantigen for combination immunotherapy of colorectal cancer.
      ]. However, these drugs’ poor solubility and unfavorable pharmacokinetics have desisted them from being used together with immunotherapy [
      • Pockros P.J.
      • Guyader D.
      • Patton H.
      • Tong M.J.
      • Wright T.
      • McHutchison J.G.
      • et al.
      Oral resiquimod in chronic HCV infection: Safety and efficacy in 2 placebo-controlled, double-blind phase IIa studies.
      ,
      • Kasturi S.P.
      • Skountzou I.
      • Albrecht R.A.
      • Koutsonanos D.
      • Hua T.
      • Nakaya H.I.
      • et al.
      Programming the magnitude and persistence of antibody responses with innate immunity.
      ,
      • Lynn G.M.
      • Laga R.
      • Darrah P.A.
      • Ishizuka A.S.
      • Balaci A.J.
      • Dulcey A.E.
      • et al.
      In vivo characterization of the physicochemical properties of polymer-linked TLR agonists that enhance vaccine immunogenicity.
      ]. The engineering of these drugs using nanocarriers could overcome this problem. Indeed, nanoparticles can be used to effectively encode more adjuvants and neoantigens and to enhance immune response. Adjuvants in neoantigenic vaccines promoted the response of cytotoxic T cells to specific neoantigens, leading to complete tumor destruction when combined with immune checkpoint blockade.

      Ongoing clinical trials for neoantigens vaccines

      The in vitro transcribed mRNAs have been administered differently and formulated as naked mRNA in buffer or LNP. These studies are based on the knowledge generated by Theilemans et al. showing that it is possible to generate powerful, clinical-grade IVT mRNA DC vaccines through electroporation [
      • Wilgenhof S.
      • Van Nuffel A.M.T.
      • Benteyn D.
      • Corthals J.
      • Aerts C.
      • Heirman C.
      • et al.
      A phase IB study on intravenous synthetic mRNA electroporated dendritic cell immunotherapy in pretreated advanced melanoma patients.
      ,
      • Wilgenhof S.
      • Corthals J.
      • Heirman C.
      • Van Baren N.
      • Lucas S.
      • Kvistborg P.
      • et al.
      Phase II study of autologous monocyte-derived mRNA electroporated dendritic cells (TriMixDC-MEL) plus ipilimumab in patientswith pretreated advanced melanoma.
      ,
      • Wilgenhof S.
      • Corthals J.
      • Van Nuffel A.M.T.
      • Benteyn D.
      • Heirman C.
      • Bonehill A.
      • et al.
      Long-term clinical outcome of melanoma patients treated with messenger RNA-electroporated dendritic cell therapy following complete resection of metastases.
      ,
      • Wilgenhof S.
      • Van Nuffel A.M.T.
      • Corthals J.
      • Heirman C.
      • Tuyaerts S.
      • Benteyn D.
      • et al.
      Therapeutic vaccination with an autologous mRNA electroporated dendritic cell vaccine in patients with advanced melanoma.
      ,
      • Jansen Y.
      • Kruse V.
      • Corthals J.
      • Schats K.
      • van Dam P.J.
      • Seremet T.
      • et al.
      A randomized controlled phase II clinical trial on mRNA electroporated autologous monocyte-derived dendritic cells (TriMixDC-MEL) as adjuvant treatment for stage III/IV melanoma patients who are disease-free following the resection of macrometastases.
      ]. Various studies have been conducted to find a way to directly deliver neo-antigen mRNA to APCs [
      • Dörrie J.
      • Schaft N.
      • Schuler G.
      • Schuler-Thurner B.
      Therapeutic cancer vaccination with ex vivo rna-transfected dendritic cells—an update.
      ,
      • Kowalski P.S.
      • Rudra A.
      • Miao L.
      • Anderson D.G.
      Delivering the Messenger: Advances in Technologies for Therapeutic mRNA Delivery.
      ].
      Shahin et al. identified somatic mutations in tumor biopsies of 13 patients with stage III/IV using whole genome/exome and RNA sequencing techniques compared to control. After ranking mutations, they predicted binding affinity to patients’ HLA-I/II molecules. mRNA vaccines were generated against HLA-I and HLA-II, and mRNA doses of 0.5–1 µg per vaccination course and injected in the inguinal lymph nodes. Patients with tumors displaying TAAs such as NY-ESO-1 and tyrosinase received an mRNA-based vaccine targeting these TAAs [
      • Kranz L.M.
      • Diken M.
      • Haas H.
      • Kreiter S.
      • Loquai C.
      • Reuter K.C.
      • et al.
      Systemic RNA delivery to dendritic cells exploits antiviral defence for cancer immunotherapy.
      ]. The results were encouraging: eight patients had no radiologically detectable tumors when neoepitope vaccination started and remained without recurrence in 12–33 -months follow-up; five patients had the metastatic disease before vaccination, and two of them experienced objective responses, a third patient exhibited complete response for combined treatment of PD-1 blocking antibody. All patients showed Tcell responses against neoepitopes with 60% response. The same strategy was tested in a subsequent clinical trial with mRNA developed based on somatic mutations and LNP adjuvant delivered intravenously in patients with triple-negative breast cancer. Various drug administration methods could impact the efficacy of mRNA vaccination, as previously observed in animal studies using nanoparticle vaccines with neoantigen peptides linked to TLR7/8 agonist [
      • Baharom F.
      • Ramirez-Valdez R.A.
      • Tobin K.K.
      • Yamane H.
      • Dutertre C.-A.
      • Khalilnezhad A.
      • et al.
      Intravenous Nanoparticle Vaccination Generates Stem-Like TCF1+ Neoantigen-Specific CD8+ T Cells.
      ]. The authors showed that intravenous injection (i.v.) vaccination induced a higher proportion of CF1 + PD-1 + CD8+ T cells versus subcutaneous injection. Additionally, stem cells were induced by i.v injection, whereas effector genes were induced by subcutaneous injection [
      • Baharom F.
      • Ramirez-Valdez R.A.
      • Tobin K.K.
      • Yamane H.
      • Dutertre C.-A.
      • Khalilnezhad A.
      • et al.
      Intravenous Nanoparticle Vaccination Generates Stem-Like TCF1+ Neoantigen-Specific CD8+ T Cells.
      ]. Various clinical trials are currently investigating safety and efficacy of neo-antigens mRNA using different delivery methods and formulations either alone or in combination with other therapies. Ongoing clinical trials for neoantigen vaccinations for cancer therapy are summarized in Table 5.
      Table 5Ongoing clinical trials investigating cancer neo-antigen vaccines.
      Ongoing clinical trials investigating cancer neo-antigen vaccines StudyCancer TypePhaseNeo AntigenModalityCo-treatmentStatus
      NCT03639714Solid tumorsI/IIGRT-C901/2NNNivolumab/ipilimumabRecruiting
      NCT04864379Solid tumorsIiNeo-Vac-P01NNAnti-PD-1Recruiting
      NCT04072900MelanomaIrhGM-CSFNNAnti-PD-1Recruiting
      NCT02287428GlioblastomaIPersonalized NeoAntigen VaccineNNPembrolizumab/ Temozolomide/Radiation TehrapyRecruiting
      NCT03361852Follicular LymphomaINeo Vaxs.c.RituximabNot yet recruiting
      NCT03219450Lymphocytic LeukemiaINeoVaxs.c.Pembrolimuzab/CyclophosphamideNot yet recruiting
      NCT02950766Kidney CancerINeoVaxs.c.IpilimumabRecruiting
      NCT04810910Resectable Pancreatic CancerIiNeo-Vac-P01/ GM-CSFNNNANot yet recruiting
      NCT04024878Ovarian CancerINeoVaxs.c.NivolumabRecruiting
      NCT03953235Solid tumorsI/IIGRT-C903/4NNNivolumab/ipilimumabRecruiting
      NCT03807102Lung CancerI/IINeoantigen Tumor VaccineNNNARecruiting
      NCT04087252Solid tumorsITumor neoantigeni.m.NARecruiting
      NCT03359239Urothelial/Bladder Cancer, NOSIMultipeptide Personalized Neoantigen Vaccine (PGV001, ICLC)NNAtezolizumabRecruiting
      NCT04749641Diffuse Intrinsic Pontine GliomaIHistone H3.3-K27M Neoantigen Vaccine Therapys.c.NARecruiting
      NCT04799431mPCmCRCINeoantigen Vaccine with Poly-ICLC adjuvants.c.RetifanlimabNot yet recruiting
      NCT04912765Solid TumorsIINeoantigen Dendritic Cell Vaccinei.d..NivolumabRecruiting
      NCT04397926NSCLCIIndividualized neoantigen peptides vaccines.c.NARecruiting
      NCT04487093NSCLCIneoantigen vaccines.c.
      • 1)
        EGFR-TKI
        Anti-angiogenesis
      Recruiting
      NCT03122106Pancreatic cancerIPersonalized neoantigen DNA vaccineNNNAActive, not recruiting
      NCT03956056Pancreatic cancerNeoantigen Peptide Vaccine, Poly ICLCs.c.NARecruiting
      NCT03199040TNBCNeoantigen DNA vaccine, TDS-IM system (Inchor Medical Systems)NNDurvalumabRecruiting
      NCT03655756Melanoma Stage III/IVIIFx-Hu2.0s.c.NAActive, not recruiting
      NCT04397003Extensive-stage SCLCIINeoantigen DNA vaccineNNDurvalumabNot yet recruiting
      NCT02129075Cutaneous, Mucosal and Ocular MelanomaIIDEC-205/NY-ESO-1 Fusion Protein CDX-1401, Neoantigen-based Melanoma-Poly-ICLC Vaccines.c.NAActive, not recruiting
      NCT04266730Squamous NSCLC

      SCC of Head and Neck
      IPANDA-VACs.c.PembrolizumabNot yet recruiting
      NCT03558945Pancreatic TumorIPersonalized neoantigen vaccines.c.NARecruiting
      NCT03468244Solid tumors, lymphomaNNNaked mRNAs.c.NARecruiting
      NCT03815058Metastatic melanomaIILNPi.v.PembrolizumabRecruiting
      NCT03897881High-risk melanomaIINNNNPembrolizumabRecruiting
      NCT03908671Esophageal cancer, NSCLCNNLNPs.c.NANot yet Recr4 times

      uiting
      NCT04161755Pancreas cancerINNNNAtezolizumab, chemotherapyRecruiting
      Abbreviations: i.d., intradermal; i.m., intramuscular; i.n., intranodal; i.v., intravenous; s.c., subcutaneous; NN, not known, NSCL, non-small cell lung cancer; SCC, squamous cell cancer; TAA, tumor-associated antigen; TNBC, triple negative breast cancer; LNP, lipid nanoparticle; NA, not applicable; mCRC, metastatic colorectal cancer; mPC, metastatic pancreatic cancer; TNBC, triple negative breast cancer, SCLC, small cell lung cancer.

      Conclusions

      A new age of cancer vaccines has started with the first LNP mRNA vaccines being FDA approved as safe and effective in preventing infections by SARS-CoV-2 causing COVID-19. Such new methods could be important to other medical fields, especially therapeutic anticancer vaccines. Several clinical trials are testing LNP mRNA anti-cancer vaccines after encouraging in vitro results. Current methods for delivery of nucleic acid-based vaccines (RNA and DNA), like electroporation and intradermal needle-free system, are also advancing rapidly. Moreover, with the advent of immune therapies, stimulation of the immune system through checkpoint inhibition provides a valid rationale for the combination of therapeutic cancer vaccines together with immune-stimulating agents. Additional methods to further stabilize vaccines in the blood system should be considered in future research. DNA vaccines with more efficient delivery methods and combined with nanoparticles’ adjuvants could become a valid and potentially superior alternative to current RNA vaccines. In fact, DNA vaccines are simpler to design. With the impetus to the vaccination field, significant improvements are also expected in cellular and peptide-based anticancer vaccines.

      CRediT authorship contribution statement

      Navid Sobhani: Conceptualization, Supervision, Data curation, Visualization, Writing – original draft, Reviewing and editing. Bruna Scaggiante: Conceptualization, Data curation, Formal analysis, Supervision, Writing and editing the draft. Rachel Morris: Data curation, Conceptualization, Software, Visualization, Writing – original draft. Dafei Chai: Conceptualization, Investigation, Visualziation, Writing and editing. Martina Catalano: Data curation, Investigation, Resources, Software, Visualization, Writing – review & editing. Dana Rae Tardiel-Cyril: Data curation, Formal analysis, Methodology, Project administartion, Writing – review & editing. Praveen Neeli: Conceptualization, Software, Visualization, Writing and editing. Giandomenico Roviello: Conceptualization, Formal analysis, Supervision, Writing – original draft. Giuseppina Mondani: Conceptualization, Validation, Writing – review & editing. Yong Li: Conceptualization, Formal analysis, Supervision, Writing – review & editing.

      Declaration of Competing Interest

      The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

      References

        • Sung H.
        • Ferlay J.
        • Siegel R.L.
        • Laversanne M.
        • Soerjomataram I.
        • Jemal A.
        • et al.
        Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries.
        CA: A Cancer Journal for Clinicians. 2021; 71: 209-249
        • Zitvogel L.
        • Tesniere A.
        • Kroemer G.
        Cancer despite immunosurveillance: immunoselection and immunosubversion.
        Nature Reviews Immunology. 2006; 6: 715-727https://doi.org/10.1038/nri1936
        • Duarte J.H.
        Individualized neoantigen vaccines.
        Nat Res. 2021; 2020
        • Zamora A.E.
        • Crawford J.C.
        • Thomas P.G.
        Hitting the target: how T cells detect and eliminate tumors.
        Journal of Immunology. 2018; 200: 392-399
        • Pedersen S.R.
        • Sørensen M.R.
        • Buus S.
        • Christensen J.P.
        • Thomsen A.R.
        Comparison of Vaccine-Induced Effector CD8 T Cell Responses Directed against Self- and Non–Self-Tumor Antigens: Implications for Cancer Immunotherapy.
        Journal of Immunology. 2013; 191: 3955-3967https://doi.org/10.4049/jimmunol.1300555
        • Hollingsworth R.E.
        • Jansen K.
        Turning the corner on therapeutic cancer vaccines.
        npj Vaccines. 2019; 4: 1-10https://doi.org/10.1038/s41541-019-0103-y
        • Belli C.
        • Trapani D.
        • Viale G.
        • D'Amico P.
        • Duso B.A.
        • Della Vigna P.
        • et al.
        Targeting the microenvironment in solid tumors.
        Cancer Treatment Reviews. 2018; 65: 22-32
        • Vedenko A.
        • Panara K.
        • Goldstein G.
        • Ramasamy R.
        • Arora H.
        Tumor microenvironment and nitric oxide: Concepts and mechanisms.
        Advances in Experimental Medicine and Biology. 2020; 1277: 143-158https://doi.org/10.1007/978-3-030-50224-9_10
        • Roma-Rodrigues C.
        • Mendes R.
        • Baptista P.
        • Fernandes A.
        Targeting tumor microenvironment for cancer therapy.
        International Journal of Molecular Sciences. 2019; 20: 840
        • Peng M.
        • Mo Y.
        • Wang Y.
        • Wu P.
        • Zhang Y.
        • Xiong F.
        • et al.
        Neoantigen vaccine: An emerging tumor immunotherapy.
        Mol Cancer. 2019; 18https://doi.org/10.1186/s12943-019-1055-6
        • Jou J.
        • Harrington K.J.
        • Zocca M.B.
        • Ehrnrooth E.
        • Cohen E.E.W.
        The changing landscape of therapeutic cancer vaccines-novel platforms and neoantigen identification.
        Clinical Cancer Research. 2021; 27: 689-703https://doi.org/10.1158/1078-0432.CCR-20-0245
        • Polack F.P.
        • Thomas S.J.
        • Kitchin N.
        • Absalon J.
        • Gurtman A.
        • Lockhart S.
        • et al.
        Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine.
        New England Journal of Medicine. 2020; 383: 2603-2615
        • Kreiter S.
        • Selmi A.
        • Diken M.
        • Koslowski M.
        • Britten C.M.
        • Huber C.
        • et al.
        Intranodal vaccination with naked antigen-encoding RNA elicits potent prophylactic and therapeutic antitumoral immunity.
        Cancer Research. 2010; 70: 9031-9040https://doi.org/10.1158/0008-5472.CAN-10-0699
        • Kallen K.-J.
        • Heidenreich R.
        • Schnee M.
        • Petsch B.
        • Schlake T.
        • Thess A.
        • et al.
        A novel, disruptive vaccination technology: Self-adjuvanted RNActive ® vaccines.
        Hum Vaccines Immunother. 2013; 9: 2263-2276
        • Belnoue E.
        • Leystra A.A.
        • Carboni S.
        • Cooper H.S.
        • Macedo R.T.
        • Harvey K.N.
        • et al.
        Novel Protein-Based Vaccine against Self-Antigen Reduces the Formation of Sporadic Colon Adenomas in Mice.
        Cancers (Basel). 2021; 13: 845
        • Baden L.R.
        • El Sahly H.M.
        • Essink B.
        • Kotloff K.
        • Frey S.
        • Novak R.
        • et al.
        Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine.
        New Engl J Med. 2021; 384: 403-416
        • Wadhwa A.
        • Aljabbari A.
        • Lokras A.
        • Foged C.
        • Thakur A.
        Opportunities and Challenges in the Delivery of mRNA-Based Vaccines.
        Pharmaceutics. 2020; 12: 102
        • Pardi N.
        • Hogan M.J.
        • Porter F.W.
        • Weissman D.
        mRNA vaccines — a new era in vaccinology.
        Nat Rev Drug Discov. 2018; 17: 261-279
        • Miao L.
        • Zhang Y.
        • Huang L.
        mRNA vaccine for cancer immunotherapy.
        Mol Cancer. 2021; 20: 1-23https://doi.org/10.1186/S12943-021-01335-5
        • Karikó K.
        • Muramatsu H.
        • Ludwig J.
        • Weissman D.
        Generating the optimal mRNA for therapy: HPLC purification eliminates immune activation and improves translation of nucleoside-modified, protein-encoding mRNA.
        Nucleic Acids Research. 2011; 39: e142https://doi.org/10.1093/NAR/GKR695
        • Karikó K.
        • Buckstein M.
        • Ni H.
        • Weissman D.
        Suppression of RNA Recognition by Toll-like Receptors: The Impact of Nucleoside Modification and the Evolutionary Origin of RNA.
        Immunity. 2005; 23: 165-175https://doi.org/10.1016/J.IMMUNI.2005.06.008
        • Karikó K.
        • Muramatsu H.
        • Welsh F.A.
        • Ludwig J.
        • Kato H.
        • Akira S.
        • et al.
        Incorporation of Pseudouridine Into mRNA Yields Superior Nonimmunogenic Vector With Increased Translational Capacity and Biological Stability.
        Molecular Therapy. 2008; 16: 1833https://doi.org/10.1038/MT.2008.200
        • Yang B.
        • Jeang J.
        • Yang A.
        • Wu T.C.
        • Hung C.F.
        DNA vaccine for cancer immunotherapy.
        Hum Vaccines Immunother. 2014; 10: 3153-3164https://doi.org/10.4161/21645515.2014.980686
        • Singhal P.
        • Marfatia Y.S.
        Human papillomavirus vaccine.
        Indian J Sex Transm Dis AIDS. 2009; 30: 51
        • Monsonégo J.
        Prévention du cancer du col utérin : enjeux et perspectives de la vaccination antipapillomavirus.
        Gynécologie Obs Fertil. 2006; 34: 189-201https://doi.org/10.1016/J.GYOBFE.2006.01.036
        • Peng S.
        • Ferrall L.
        • Gaillard S.
        • Wang C.
        • Chi W.-Y.
        • Huang C.-H.
        • et al.
        Development of DNA Vaccine Targeting E6 and E7 Proteins of Human Papillomavirus 16 (HPV16) and HPV18 for Immunotherapy in Combination with Recombinant Vaccinia Boost and PD-1 Antibody.
        MBio. 2021; 12: 1-19https://doi.org/10.1128/MBIO.03224-20
        • Strioga M.M.
        • Darinskas A.
        • Pasukoniene V.
        • Mlynska A.
        • Ostapenko V.
        • Schijns V.
        Xenogeneic therapeutic cancer vaccines as breakers of immune tolerance for clinical application: To use or not to use?.
        Vaccine. 2014; 32: 4015-4024https://doi.org/10.1016/J.VACCINE.2014.05.006
        • Quaglino E.
        • Riccardo F.
        • Macagno M.
        • Bandini S.
        • Cojoca R.
        • Ercole E.
        • et al.
        Chimeric DNA Vaccines against ErbB2+ Carcinomas: From Mice to Humans.
        Cancers (Basel). 2011; 3: 3225https://doi.org/10.3390/CANCERS3033225
        • English D.P.
        • Roque D.M.
        • Santin A.D.
        HER2 Expression Beyond Breast Cancer: Therapeutic Implications for Gynecologic Malignancies.
        Mol Diagn Ther. 2013; 17: 85https://doi.org/10.1007/S40291-013-0024-9
        • Lopes A.
        • Vandermeulen G.
        • Préat V.
        Cancer DNA vaccines: current preclinical and clinical developments and future perspectives.
        Journal of Experimental & Clinical Cancer Research. 2019; 38https://doi.org/10.1186/S13046-019-1154-7
        • Yuan J.
        • Ku G.Y.
        • Gallardo H.F.
        • Orlandi F.
        • Manukian G.
        • Rasalan T.S.
        • et al.
        Safety and immunogenicity of a humanand mouse gp100 DNA vaccine in a phase I trial of patients with melanoma.
        Cancer Immun a J Acad Cancer Immunol. 2009; 9: 5
        • Rice J.
        • Ottensmeier C.H.
        • Stevenson F.K.
        DNA vaccines: Precision tools for activating effective immunity against cancer.
        Nature Reviews Cancer. 2008; 8: 108-120https://doi.org/10.1038/nrc2326
      1. Abbas AK, Lichtman AH, Pillai S. Cellular and molecular immunology - 10th ed.; 2021. p. 600.

        • Tay R.E.
        • Richardson E.K.
        • Toh H.C.
        Revisiting the role of CD4+ T cells in cancer immunotherapy—new insights into old paradigms.
        Cancer Gene Therapy. 2021; 28: 5-17https://doi.org/10.1038/s41417-020-0183-x
        • Slingluff C.L.
        The present and future of peptide vaccines for cancer: Single or multiple, long or short, alone or in combination?.
        Cancer Journal. 2011; 17: 343-350https://doi.org/10.1097/PPO.0b013e318233e5b2
        • Diao L.
        • Meibohm B.
        Pharmacokinetics and pharmacokinetic-pharmacodynamic correlations of therapeutic peptides.
        Clinical Pharmacokinetics. 2013; 52: 855-868https://doi.org/10.1007/s40262-013-0079-0
        • Southwood S.
        • Sidney J.
        • Kondo A.
        • del Guercio M.F.
        • Appella E.
        • Hoffman S.
        • et al.
        Several common HLA-DR types share largely overlapping peptide binding repertoires.
        Journal of Immunology. 1998; 160: 3363-3373
        • Luparello C.
        Parathyroid Hormone-Related Protein (PTHrP): A Key Regulator of Life/Death Decisions by Tumor Cells with Potential Clinical Applications.
        Cancers (Basel). 2011; 3: 396https://doi.org/10.3390/CANCERS3010396
        • Cusi M.G.
        • Botta C.
        • Pastina P.
        • Rossetti M.G.
        • Dreassi E.
        • Guidelli G.M.
        • et al.
        Phase I trial of thymidylate synthase poly-epitope peptide (TSPP) vaccine in advanced cancer patients.
        Cancer Immunology, Immunotherapy. 2015; 64: 1159-1173https://doi.org/10.1007/S00262-015-1711-7
        • Correale P.
        • Botta C.
        • Martino E.C.
        • Ulivieri C.
        • Battaglia G.
        • Carfagno T.
        • et al.
        Phase Ib study of poly-epitope peptide vaccination to thymidylate synthase (TSPP) and GOLFIG chemo-immunotherapy for treatment of metastatic colorectal cancer patients.
        Oncoimmunology. 2016; 5https://doi.org/10.1080/2162402X.2015.1101205
        • Sato K.
        • Yamakawa Y.
        • Shizume K.
        • Satoh T.
        • Nohtomi K.
        • Demura H.
        • et al.
        Passive immunization with anti-parathyroid hormone-related protein monoclonal antibody markedly prolongs survival time of hypercalcemic nude mice bearing transplanted human PTHrP-producing tumors.
        Journal of Bone and Mineral Research. 1993; 8: 849-860https://doi.org/10.1002/JBMR.5650080711
      2. Arakawa Y, Okita Y, Narita Y. Efficacy finding cohort of a cancer peptide vaccine, TAS0313, in treating recurrent glioblastoma, vol. 39; 2021. p. 2038-2038. https://doi.org/10.1200/JCO.2021.39.15_SUPPL.2038.

        • Cleyle J.
        • Hardy M.-P.
        • Minati R.
        • Courcelles M.
        • Durette C.
        • Lanoix J.
        • et al.
        Immunopeptidomic analyses of colorectal cancers with and without microsatellite instability.
        Molecular and Cellular Proteomics. 2022; : 100228https://doi.org/10.1016/J.MCPRO.2022.100228
        • Corulli L.R.
        • Cecil D.L.
        • Gad E.
        • Koehnlein M.
        • Coveler A.L.
        • Childs J.S.
        • et al.
        Multi-Epitope-Based Vaccines for Colon Cancer Treatment and Prevention.
        Frontiers in Immunology. 2021; 12: 3533https://doi.org/10.3389/FIMMU.2021.729809/BIBTEX
        • Mun Teo M.Y.
        • Ceen Ng J.J.
        • Fong J.Y.
        • Hwang J.S.
        • Song A.A.L.
        • Hong Lim R.L.
        • et al.
        Development of a single-chain fragment variable fused-mutant HALT-1 recombinant immunotoxin against G12V mutated KRAS c olorectal cancer cells.
        PeerJ. 2021; 9https://doi.org/10.7717/PEERJ.11063
        • Kim S.
        • Kim B.J.
        • Kim I.
        • Kim J.H.
        • Kim H.K.
        • Ryu H.
        • et al.
        A phase II study of chemotherapy in combination with telomerase peptide vaccine (GV1001) as second-line treatment in patients with metastatic colorectal cancer.
        J Cancer. 2022; 13: 1363-1369https://doi.org/10.7150/JCA.70385
        • Russell S.J.
        • Peng K.-W.
        • Bell J.C.
        Oncolytic virotherapy.
        Nature Biotechnology. 2012; 30: 658https://doi.org/10.1038/NBT.2287
        • Roy D.G.
        • Geoffroy K.
        • Marguerie M.
        • Khan S.T.
        • Martin N.T.
        • Kmiecik J.
        • et al.
        Adjuvant oncolytic virotherapy for personalized anti-cancer vaccination.
        Nature Communications. 2021; 12: 1-11https://doi.org/10.1038/s41467-021-22929-z
        • Pol J.G.
        • Zhang L.
        • Bridle B.W.
        • Stephenson K.B.
        • Rességuier J.
        • Hanson S.
        • et al.
        Maraba Virus as a Potent Oncolytic Vaccine Vector.
        Molecular Therapy. 2014; 22: 420-429https://doi.org/10.1038/MT.2013.249
        • Gebert J.
        • Gelincik O.
        • Oezcan-Wahlbrink M.
        • Marshall J.D.
        • Hernandez-Sanchez A.
        • Urban K.
        • et al.
        Recurrent frameshift neoantigen vaccine elicits protective immunity with reduced tumor burden and improved overall survival in a Lynch syndrome mouse model.
        Gastroenterology. 2021; https://doi.org/10.1053/J.GASTRO.2021.06.073
        • Antonios J.P.
        • Soto H.
        • Everson R.G.
        • Orpilla J.
        • Moughon D.
        • Shin N.
        • et al.
        PD-1 blockade enhances the vaccination-induced immune response in glioma.
        JCI Insight. 2016; 1: 87059https://doi.org/10.1172/JCI.INSIGHT.87059
        • Le D.T.
        • Pardoll D.M.
        • Jaffee E.M.
        Cellular vaccine approaches.
        Cancer Journal. 2010; 16: 304-310https://doi.org/10.1097/PPO.0b013e3181eb33d7
        • Yamamoto L.
        • Amodio N.
        • Gulla A.
        • Anderson K.C.
        Harnessing the Immune System Against Multiple Myeloma: Challenges and Opportunities.
        Frontiers in Oncology. 2021; 10: 3160https://doi.org/10.3389/fonc.2020.606368
        • Keenan B.P.
        • Jaffee E.M.
        Whole cell vaccines - Past progress and future strategies.
        Seminars in Oncology. 2012; 39: 276-286https://doi.org/10.1053/j.seminoncol.2012.02.007
        • Chiang C.L.-L.
        • Coukos G.
        • Kandalaft L.E.
        Whole Tumor Antigen Vaccines: Where Are We?.
        Vaccines. 2015; 3: 344https://doi.org/10.3390/VACCINES3020344
        • Senzer N.
        • Barve M.
        • Kuhn J.
        • Melnyk A.
        • Beitsch P.
        • Lazar M.
        • et al.
        Phase I Trial of “bi-shRNAifurin/GMCSF DNA/Autologous Tumor Cell” Vaccine (FANG) in Advanced Cancer.
        Molecular Therapy. 2012; 20: 679https://doi.org/10.1038/MT.2011.269
        • Martin S.D.
        • Brown S.D.
        • Wick D.A.
        • Nielsen J.S.
        • Kroeger D.R.
        • Twumasi-Boateng K.
        • et al.
        Low Mutation Burden in Ovarian Cancer May Limit the Utility of Neoantigen-Targeted Vaccines.
        PLoS ONE. 2016; 11e0155189https://doi.org/10.1371/JOURNAL.PONE.0155189
        • Rizvi N.A.
        • Hellmann M.D.
        • Snyder A.
        • Kvistborg P.
        • Makarov V.
        • Havel J.J.
        • et al.
        Mutational landscape determines sensitivity to PD-1 blockade in non-small cell lung cancer.
        Science (80-). 2015; 348: 124-128https://doi.org/10.1126/science.aaa1348
        • Snyder A.
        • Makarov V.
        • Merghoub T.
        • Yuan J.
        • Zaretsky J.M.
        • Desrichard A.
        • et al.
        Genetic Basis for Clinical Response to CTLA-4 Blockade in Melanoma.
        New England Journal of Medicine. 2014; 371: 2189-2199https://doi.org/10.1056/nejmoa1406498
        • Salewski I.
        • Gladbach Y.S.
        • Kuntoff S.
        • Irmscher N.
        • Hahn O.
        • Junghanss C.
        • et al.
        In vivo vaccination with cell line-derived whole tumor lysates: neoantigen quality, not quantity matters.
        J Transl Med. 2020; 18: 402https://doi.org/10.1186/s12967-020-02570-y
        • Schumacher T.N.
        • Schreiber R.D.
        Neoantigens in cancer immunotherapy.
        Science (80-). 2015; 348: 69-74https://doi.org/10.1126/science.aaa4971
        • Yadav M.
        • Jhunjhunwala S.
        • Phung Q.T.
        • Lupardus P.
        • Tanguay J.
        • Bumbaca S.
        • et al.
        Predicting immunogenic tumour mutations by combining mass spectrometry and exome sequencing.
        Nature. 2014; 515: 572-576https://doi.org/10.1038/nature14001
        • Sahin U.
        • Derhovanessian E.
        • Miller M.
        • Kloke B.P.
        • Simon P.
        • Löwer M.
        • et al.
        Personalized RNA mutanome vaccines mobilize poly-specific therapeutic immunity against cancer.
        Nature. 2017; 547: 222-226https://doi.org/10.1038/nature23003
        • Ott P.A.
        • Hu Z.
        • Keskin D.B.
        • Shukla S.A.
        • Sun J.
        • Bozym D.J.
        • et al.
        An immunogenic personal neoantigen vaccine for patients with melanoma.
        Nature. 2017; 547: 217-221https://doi.org/10.1038/nature22991
        • Gubin M.M.
        • Zhang X.
        • Schuster H.
        • Caron E.
        • Ward J.P.
        • Noguchi T.
        • et al.
        Checkpoint blockade cancer immunotherapy targets tumour-specific mutant antigens.
        Nature. 2014; 515: 577-581https://doi.org/10.1038/nature13988
        • Wei S.C.
        • Duffy C.R.
        • Allison J.P.
        Fundamental mechanisms of immune checkpoint blockade therapy.
        Cancer Discov. 2018; 8: 1069-1086https://doi.org/10.1158/2159-8290.CD-18-0367
        • Campbell P.J.
        • Pleasance E.D.
        • Stephens P.J.
        • Dicks E.
        • Rance R.
        • Goodhead I.
        • et al.
        Subclonal phylogenetic structures in cancer revealed by ultra-deep sequencing.
        Proc Natl Acad Sci U S A. 2008; 105: 13081https://doi.org/10.1073/PNAS.0801523105
        • Alexandrov L.B.
        • Nik-Zainal S.
        • Wedge D.C.
        • Aparicio S.A.J.R.
        • Behjati S.
        • Biankin A.V.
        • et al.
        Signatures of mutational processes in human cancer.
        Nat. 2013; 500: 415-421https://doi.org/10.1038/nature12477
        • Lawrence M.S.
        • Stojanov P.
        • Polak P.
        • Kryukov G.V.
        • Cibulskis K.
        • Sivachenko A.
        • et al.
        Mutational heterogeneity in cancer and the search for new cancer-associated genes.
        Nat. 2013; 499: 214-218https://doi.org/10.1038/nature12213
        • Vogelstein B.
        • Papadopoulos N.
        • Velculescu V.E.
        • Zhou S.
        • Diaz L.A.
        • Kinzler K.W.
        Cancer genome landscapes.
        Science (80-). 2013; 340: 1546-1558https://doi.org/10.1126/SCIENCE.1235122/SUPPL_FILE/VOGELSTEIN.SM.COVER.PAGE.PDF
        • Rooney M.S.
        • Shukla S.A.
        • Wu C.J.
        • Getz G.
        • Hacohen N.
        Molecular and genetic properties of tumors associated with local immune cytolytic activity.
        Cell. 2015; 160: 48-61https://doi.org/10.1016/J.CELL.2014.12.033/ATTACHMENT/6429F90E-4497-4300-B031-42EEEF626695/MMC15.PDF
        • Brown S.D.
        • Warren R.L.
        • Gibb E.A.
        • Martin S.D.
        • Spinelli J.J.
        • Nelson B.H.
        • et al.
        Neo-antigens predicted by tumor genome meta-analysis correlate with increased patient survival.
        Genome Research. 2014; 24: 743https://doi.org/10.1101/GR.165985.113
        • Giannakis M.
        • Mu X.J.
        • Shukla S.A.
        • Qian Z.R.
        • Cohen O.
        • Nishihara R.
        • et al.
        Genomic Correlates of Immune-Cell Infiltrates in Colorectal Carcinoma.
        Cell Rep. 2016; 15: 857-865https://doi.org/10.1016/J.CELREP.2016.03.075/ATTACHMENT/A727252A-0701-48AD-9A01-7044E54B66A7/MMC2.XLSX
        • Hu Z.
        • Ott P.A.
        • Wu C.J.
        Towards personalized, tumour-specific, therapeutic vaccines for cancer.
        Nature Reviews Immunology. 2017; 18: 168-182https://doi.org/10.1038/nri.2017.131
        • Fritsch E.F.
        • Rajasagi M.
        • Ott P.A.
        • Brusic V.
        • Hacohen N.
        • Wu C.J.
        HLA-Binding Properties of Tumor Neoepitopes in Humans.
        Cancer Immunol Res. 2014; 2: 522-529https://doi.org/10.1158/2326-6066.CIR-13-0227
        • Rajasagi M.
        • Shukla S.A.
        • Fritsch E.F.
        • Keskin D.B.
        • DeLuca D.
        • Carmona E.
        • et al.
        Systematic identification of personal tumor-specific neoantigens in chronic lymphocytic leukemia.
        Blood. 2014; 124: 453-462https://doi.org/10.1182/BLOOD-2014-04-567933
        • Sonntag K.
        • Hashimoto H.
        • Eyrich M.
        • Menzel M.
        • Schubach M.
        • Döcker D.
        • et al.
        Immune monitoring and TCR sequencing of CD4 T cells in a long term responsive patient with metastasized pancreatic ductal carcinoma treated with individualized, neoepitope-derived multipeptide vaccines: a case report.
        J Transl Med. 2018; 16https://doi.org/10.1186/S12967-018-1382-1
        • Keskin D.B.
        • Anandappa A.J.
        • Sun J.
        • Tirosh I.
        • Mathewson N.D.
        • Li S.
        • et al.
        Neoantigen vaccine generates intratumoral T cell responses in phase Ib glioblastoma trial.
        Nat. 2018; 565: 234-239https://doi.org/10.1038/s41586-018-0792-9
        • Hilf N.
        • Kuttruff-Coqui S.
        • Frenzel K.
        • Bukur V.
        • Stevanović S.
        • Gouttefangeas C.
        • et al.
        Actively personalized vaccination trial for newly diagnosed glioblastoma.
        Nat. 2018; 565: 240-245https://doi.org/10.1038/s41586-018-0810-y
        • Johanns T.M.
        • Miller C.A.
        • Liu C.J.
        • Perrin R.J.
        • Bender D.
        • Kobayashi D.K.
        • et al.
        Detection of neoantigen-specific T cells following a personalized vaccine in a patient with glioblastoma.
        Oncoimmunology. 2019; 8https://doi.org/10.1080/2162402X.2018.1561106/SUPPL_FILE/KONI_A_1561106_SM4321.XLSX
      3. A Study of Autogene Cevumeran (RO7198457) as a Single Agent and in Combination With Atezolizumab in Participants With Locally Advanced or Metastatic Tumors - Full Text View - ClinicalTrials.gov; n.d.

        • Sarkizova S.
        • Klaeger S.
        • Le P.M.
        • Li L.W.
        • Oliveira G.
        • Keshishian H.
        • et al.
        A large peptidome dataset improves HLA class I epitope prediction across most of the human population.
        Nature Biotechnology. 2019; 38: 199-209https://doi.org/10.1038/s41587-019-0322-9
        • Lin Z.
        • Zhang Y.
        • Cai H.
        • Zhou F.
        • Gao H.
        • Deng L.
        • et al.
        A PD-L1-based cancer vaccine elicits antitumor immunity in a mouse melanoma model.
        Molecular Therapy - Oncolytics. 2019; 14: 222https://doi.org/10.1016/J.OMTO.2019.06.002
        • Chen J.
        • Liu H.
        • Jehng T.
        • Li Y.
        • Chen Z.
        • Lee K.D.
        • et al.
        A Novel Anti-PD-L1 Vaccine for Cancer Immunotherapy and Immunoprevention.
        Cancers (Basel). 2019; 11https://doi.org/10.3390/CANCERS11121909
        • Kaumaya P.T.P.
        • Guo L.
        • Overholser J.
        • Penichet M.L.
        • Bekaii-Saab T.
        Immunogenicity and antitumor efficacy of a novel human PD-1 B-cell vaccine (PD1-Vaxx) and combination immunotherapy with dual trastuzumab/pertuzumab-like HER-2 B-cell epitope vaccines (B-Vaxx) in a syngeneic mouse model.
        Oncoimmunology. 2020; 9https://doi.org/10.1080/2162402X.2020.1818437
        • Thompson E.A.
        • Liang F.
        • Lindgren G.
        • Sandgren K.J.
        • Quinn K.M.
        • Darrah P.A.
        • et al.
        Human Anti-CD40 Antibody and Poly IC:LC Adjuvant Combination Induces Potent T Cell Responses in the Lung of Nonhuman Primates.
        Journal of Immunology. 2015; 195: 1015-1024https://doi.org/10.4049/jimmunol.1500078
        • Melssen M.M.
        • Petroni G.R.
        • Chianese-Bullock K.A.
        • Wages N.A.
        • Grosh W.W.
        • Varhegyi N.
        • et al.
        A multipeptide vaccine plus toll-like receptor agonists LPS or polyICLC in combination with incomplete Freund’s adjuvant in melanoma patients.
        Journal for ImmunoTherapy of Cancer. 2019; 7: 163https://doi.org/10.1186/s40425-019-0625-x
        • Pockros P.J.
        • Guyader D.
        • Patton H.
        • Tong M.J.
        • Wright T.
        • McHutchison J.G.
        • et al.
        Oral resiquimod in chronic HCV infection: Safety and efficacy in 2 placebo-controlled, double-blind phase IIa studies.
        Journal of Hepatology. 2007; 47: 174-182https://doi.org/10.1016/j.jhep.2007.02.025
        • Kasturi S.P.
        • Skountzou I.
        • Albrecht R.A.
        • Koutsonanos D.
        • Hua T.
        • Nakaya H.I.
        • et al.
        Programming the magnitude and persistence of antibody responses with innate immunity.
        Nature. 2011; 470: 543-550https://doi.org/10.1038/nature09737
        • Lynn G.M.
        • Laga R.
        • Darrah P.A.
        • Ishizuka A.S.
        • Balaci A.J.
        • Dulcey A.E.
        • et al.
        In vivo characterization of the physicochemical properties of polymer-linked TLR agonists that enhance vaccine immunogenicity.
        Nature Biotechnology. 2015; 33: 1201-1210https://doi.org/10.1038/nbt.3371
        • Ni Q.
        • Zhang F.
        • Liu Y.
        • Wang Z.
        • Yu G.
        • Liang B.
        • et al.
        A bi-adjuvant nanovaccine that potentiates immunogenicity of neoantigen for combination immunotherapy of colorectal cancer.
        Science Advances. 2020; 6https://doi.org/10.1126/sciadv.aaw6071
        • Wilgenhof S.
        • Van Nuffel A.M.T.
        • Benteyn D.
        • Corthals J.
        • Aerts C.
        • Heirman C.
        • et al.
        A phase IB study on intravenous synthetic mRNA electroporated dendritic cell immunotherapy in pretreated advanced melanoma patients.
        Annals of Oncology. 2013; 24: 2686-2693https://doi.org/10.1093/annonc/mdt245
        • Wilgenhof S.
        • Corthals J.
        • Heirman C.
        • Van Baren N.
        • Lucas S.
        • Kvistborg P.
        • et al.
        Phase II study of autologous monocyte-derived mRNA electroporated dendritic cells (TriMixDC-MEL) plus ipilimumab in patientswith pretreated advanced melanoma.
        Journal of Clinical Oncology. 2016; 34: 1330-1338https://doi.org/10.1200/JCO.2015.63.4121
        • Wilgenhof S.
        • Corthals J.
        • Van Nuffel A.M.T.
        • Benteyn D.
        • Heirman C.
        • Bonehill A.
        • et al.
        Long-term clinical outcome of melanoma patients treated with messenger RNA-electroporated dendritic cell therapy following complete resection of metastases.
        Cancer Immunology, Immunotherapy. 2015; 64: 381-388https://doi.org/10.1007/s00262-014-1642-8
        • Wilgenhof S.
        • Van Nuffel A.M.T.
        • Corthals J.
        • Heirman C.
        • Tuyaerts S.
        • Benteyn D.
        • et al.
        Therapeutic vaccination with an autologous mRNA electroporated dendritic cell vaccine in patients with advanced melanoma.
        Journal of Immunotherapy. 2011; 34: 448-456https://doi.org/10.1097/CJI.0b013e31821dcb31
        • Jansen Y.
        • Kruse V.
        • Corthals J.
        • Schats K.
        • van Dam P.J.
        • Seremet T.
        • et al.
        A randomized controlled phase II clinical trial on mRNA electroporated autologous monocyte-derived dendritic cells (TriMixDC-MEL) as adjuvant treatment for stage III/IV melanoma patients who are disease-free following the resection of macrometastases.
        Cancer Immunology, Immunotherapy. 2020; 69: 2589-2598https://doi.org/10.1007/s00262-020-02618-4
        • Dörrie J.
        • Schaft N.
        • Schuler G.
        • Schuler-Thurner B.
        Therapeutic cancer vaccination with ex vivo rna-transfected dendritic cells—an update.
        Pharmaceutics. 2020; 12: 92https://doi.org/10.3390/pharmaceutics12020092
        • Kowalski P.S.
        • Rudra A.
        • Miao L.
        • Anderson D.G.
        Delivering the Messenger: Advances in Technologies for Therapeutic mRNA Delivery.
        Molecular Therapy. 2019; 27: 710-728https://doi.org/10.1016/j.ymthe.2019.02.012
        • Kranz L.M.
        • Diken M.
        • Haas H.
        • Kreiter S.
        • Loquai C.
        • Reuter K.C.
        • et al.
        Systemic RNA delivery to dendritic cells exploits antiviral defence for cancer immunotherapy.
        Nature. 2016; 534: 396-401https://doi.org/10.1038/nature18300
        • Baharom F.
        • Ramirez-Valdez R.A.
        • Tobin K.K.
        • Yamane H.
        • Dutertre C.-A.
        • Khalilnezhad A.
        • et al.
        Intravenous Nanoparticle Vaccination Generates Stem-Like TCF1+ Neoantigen-Specific CD8+ T Cells.
        Nature Immunology. 2021; 22: 41https://doi.org/10.1038/S41590-020-00810-3