Neoantigen-specific T-cell Research Articles

T-cell Responses to Individualized Neoantigen Therapy mRNA-4157 (V940) Alone or in Combination with Pembrolizumab in the Phase 1 KEYNOTE-603 Study.

mRNA-4157 (V940) is an individualized neoantigen therapy targeting up to 34 patient-specific tumor neoantigens to induce T-cell responses and potentiate antitumor activity. We report mechanistic insights into the immunogenicity of mRNA-4157 via characterization of T-cell responses to neoantigens from the first-in-human, phase 1, KEYNOTE-603 study (NCT03313778) in patients with resected non-small cell lung cancer (Part A: 1-mg mRNA-4157, n = 4) or resected cutaneous melanoma (Part D: 1-mg mRNA-4157 + 200-mg pembrolizumab, n = 12). Safety, tolerability, and immunogenicity were assessed. All patients experienced ≥1 treatment-emergent adverse event; there were no grade 4/5 adverse events or dose-limiting toxicities. mRNA-4157 alone induced consistent de novo and strengthened preexisting T-cell responses to targeted neoantigens. Following combination therapy, sustained mRNA-4157-induced neoantigen-specific T-cell responses and expansion of cytotoxic CD8 and CD4 T cells were observed. These findings show the potential of a novel mRNA individualized neoantigen therapy approach in oncology. Significance: The safety and immunogenicity results from this phase 1 study of mRNA-4157 as adjuvant monotherapy or combination therapy with pembrolizumab show generation of de novo and enhancement of existing neoantigen-specific T-cell responses and provide mechanistic proof of concept to support further development of mRNA-4157 for patients with resected solid tumors. See related commentary by Berraondo et al., p. 2021.

Inhibition of DNMTs increases neoantigen-reactive T-cell toxicity against microsatellite-stable colorectal cancer in combination with radiotherapy

The therapeutic efficacy of immunotherapy is limited in the majority of colorectal cancer patients due to the low mutational and neoantigen burdens in this immunogenically “cold” microsatellite stability-colorectal cancer (MSS-CRC) cohort. Here, we showed that DNA methyltransferase (DNMT) inhibition upregulated neoantigen-bearing gene expression in MSS-CRC, resulting in increased neoantigen presentation by MHC class I in tumor cells and leading to increased neoantigen-specific T-cell activation in combination with radiotherapy. The cytotoxicity of neoantigen-reactive T cells (NRTs) to DNMTi-treated cancer cells was highly cytotoxic, and these cells secreted high IFNγ levels targeting MSS-CRC cells after ex vivo expansion of NRTs with DNMTi-treated tumor antigens. Moreover, the therapeutic efficacy of NRTs further increased when NRTs were combined with radiotherapy in vivo. Administration of DNMTi-augmented NRTs and radiotherapy achieved an ∼50 % complete response and extended survival time in an immunocompetent MSS-CRC animal model. Moreover, remarkably, splenocytes from these mice exhibited neoantigen-specific T-cell responses, indicating that radiotherapy in combination with DNMTi-augmented NRTs prolonged and increased neoantigen-specific T-cell toxicity in MSS-CRC patients. In addition, these DNMTi-augmented NRTs markedly increase the therapeutic efficacy of cancer vaccines and immune checkpoint inhibitors (ICIs). These data suggest that a combination of radiotherapy and epi-immunotherapeutic agents improves the function of ex vivo-expanded neoantigen-reactive T cells and increases the tumor-specific cytotoxic effector population to enhance therapeutic efficacy in MSS-CRC.

Neoantigen-augmented iPSC cancer vaccine combined with radiotherapy promotes antitumor immunity in poorly immunogenic cancers

Although irradiated induced-pluripotent stem cells (iPSCs) as a prophylactic cancer vaccine elicit an antitumor immune response, the therapeutic efficacy of iPSC-based cancer vaccines is not promising due to their insufficient antigenicity and the immunosuppressive tumor microenvironment. Here, we found that neoantigen-engineered iPSC cancer vaccines can trigger neoantigen-specific T cell responses to eradicate cancer cells and increase the therapeutic efficacy of RT in poorly immunogenic colorectal cancer (CRC) and triple-negative breast cancer (TNBC). We generated neoantigen-augmented iPSCs (NA-iPSCs) by engineering AAV2 vector carrying murine neoantigens and evaluated their therapeutic efficacy in combination with radiotherapy. After administration of NA-iPSC cancer vaccine and radiotherapy, we found that ~60% of tumor-bearing mice achieved a complete response in microsatellite-stable CRC model. Furthermore, splenocytes from mice treated with NA-iPSC plus RT produced high levels of IFNγ secretion in response to neoantigens and had a greater cytotoxicity to cancer cells, suggesting that the NA-iPSC vaccine combined with radiotherapy elicited a superior neoantigen-specific T-cell response to eradicate cancer cells. The superior therapeutic efficacy of NA-iPSCs engineered by mouse TNBC neoantigens was also observed in the syngeneic immunocompetent TNBC mouse model. We found that the risk of spontaneous lung and liver metastasis was dramatically decreased by NA-iPSCs plus RT in the TNBC animal model. Altogether, these results indicated that autologous iPSC cancer vaccines engineered by neoantigens can elicit a high neoantigen-specific T-cell response, promote tumor regression, and reduce the risk of distant metastasis in combination with local radiotherapy.

Abstract 3855: Kinetics of neoantigen-specific T cells in post-transplant relapse

Abstract Introduction: Graft-versus-leukemia effect (GVL) underpins the curative mechanism of allogeneic stem cell transplantation (alloSCT) for acute leukemias. Donor-derived T cells can recognize various antigens, including human leukocyte antigen (HLA), minor-histocompatibility antigens (miHA), over-expressed antigens, or neoantigens derived from somatic mutations of leukemia. However, the role of neoantigens has not been fully investigated in GVL. Here, we aimed to predict neoantigens and identify neoantigen-reactive T cells using samples after alloSCT. Materials: Leukemia blasts were purified from relapsed samples. Recipient saliva or T cells from pre-transplant peripheral blood (PB) were used as a recipient germline control, while donor monocyte or CD34 cells were used as donor controls. DNA/RNA isolated from these specimens were analyzed for whole exome sequencing (WES) paired with RNAseq. Somatic mutations were called using blasts and recipient germline controls by mutect and mpileup and annotation with SnpEff. Somatic mutations with variant allele frequency >20% were screened for neoantigen prediction bound to recipient HLA (IC50 < 500nM) by pVAC-seq. We also genotyped 73 SNPs associated with publicly known miHAs. Serial PB were stained for HLA-A*02:01 tetramers loaded with neoantigens or CMVpp65. T cells were stimulated with neoantigens for 10 days and tested for cytokine production in responses to target or control peptides. Results: We screened neoantigens in 8 patients relapsing after alloSCT (7 acute myeloid leukemia and 1 acute lymphoblastic leukemia) and their donors (4 matched siblings, 1 matched unrelated, 3 haploidentical). In 7 subjects, WES/RNAseq showed an average of 273 somatic mutations per patient (range 108- 609). In one subject, targeted next-generation sequencing was used to detect 2 somatic mutations. Among these mutations, seven out of eight subjects (87.5%) had potential neoantigen candidates, with a median number of 9 antigens per subject. In contrast, only 2 subjects (25%) had potential miHA. UPN8, a responder to donor lymphocyte infusion (DLI), showed dominant CMVpp65-specific T cells at the time of relapse and emergence of TP53- (neoantigen) or HA-2- (miHA) specific T cells after relapse. HA-2-specific T cells upregulated PD-1 expression at the time of graft-versus-host disease (GVHD), indicating activation of these miHA-specific T cells during GVHD. In two subjects (UPN3 and UPN8) who achieved long-term remission after DLI, CD8 T cells specific to neoantigens were detectable by IFN-γ/CD107a production in reaction to mutant peptides (SDE2.pK123X or TP53.pR248W) from post-relapse samples. Discussion: Our study showed the feasibility of in-silico neoantigens prediction and neoantigen-specific T-cell detection from a subject who developed relapse after alloSCT. Further investigation is needed to test if neoepitope burden and miHA disparity could correlate with transplant outcomes. Citation Format: Biswas Neupane, Jui-En Ray Lee, Kedwin Ventura, Kayla Parr, Kevin Quann, Sawa Ito. Kinetics of neoantigen-specific T cells in post-transplant relapse [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3855.

Abstract 5309: ATOR-4066, a Neo-X-Prime™ bispecific antibody targeting CD40 and CEACAM5, induces tumor localized immune cell activation in preclinical in vivo tumor model

Abstract ATOR-4066 is a preclinical stage bispecific antibody targeting CD40 and CEACAM5, based on Alligator’s novel Neo-X-Prime™ antibody technology platform. ATOR-4066 induces a neoantigen specific T-cell response by simultaneous binding to CD40 on myeloid cells such as antigen presenting cells (APCs) and to CEACAM5 on tumor cells. CEACAM5 is a tumor-associated antigen highly expressed on several cancer indications such as colorectal and gastric cancer, as well as on tumor-derived material. ATOR-4066 treatment results in (1) CEACAM5-conditional CD40-mediated activation of APCs and (2) enhanced uptake of tumor-derived material, leading to cross-presentation of neoantigen and priming of neoantigen-specific T cells, resulting in enhanced tumor cell killing. We have previously shown evidence of a potent anti-tumor effect of ATOR-4066 in vivo, superior to the effects observed with the corresponding CD40 mAb. Moreover, we have demonstrated CEACAM5-dependent activation of CD40-expressing cells in vitro, and an ability to mediate co-localization of CEACAM5-expressing tumor debris and CD40 expressing APCs. In addition, ATOR-4066 was shown to induce CEACAM5-conditional activation of tumor-infiltrating CD40-expressing immune cells in dissociated primary human tumor material from colorectal and gastric cancer patients. Here we present data further elucidating the mode of action of ATOR-4066 in vivo. Following ATOR-4066 treatment, tumors and lymph nodes were isolated from human CD40 transgenic mice bearing MC38 tumors expressing human CEACAM5. Flow cytometry analysis shows an increased number of tumor-infiltrating immune cells in mice treated with ATOR-4066 compared to treatments with CD40 mAb or vehicle. The study also reveals upregulation of co-stimulatory molecules such as CD86 on DCs and macrophages after treatment with ATOR-4066 compared to groups treated with CD40 mAb or vehicle. The effect was localized to the tumor microenvironment and not observed in tumor draining lymph nodes, confirming previous in vitro results demonstrating CEACAM5-conditional immune activation. Moreover, RNA-sequencing of tumor samples displayed distinct transcriptomic alterations following ATOR-4066 treatment vs. CD40 mAb or vehicle treatment in vivo. In contrast, RNA-sequencing of peripheral blood in ATOR-4066 treated mice showed only small transcriptomic differences compared to the vehicle treated group, but distinct from mice treated with a CD40 mAb, further demonstrating the CEACAM5 dependent response of ATOR-4066. In summary, these preclinical data demonstrate that ATOR-4066 activates infiltrating myeloid cells resulting in increases in activated tumor infiltrating T cells, thus creating a pro-inflammatory tumor microenvironment, which strongly supports further development and clinical testing of ATOR-4066. Citation Format: Hampus Andersson, Ida Uddbäck, Mona Celander, Maria Johansson, Lill Ljung, Anneli Nilsson, Amulya Krishna Shetty, David Gomez Jimenez, Mattias Levin, Sara Fritzell, Laura von Schantz, Malin Lindstedt, Karin Hägerbrand, Anette Sundstedt, Peter Ellmark. ATOR-4066, a Neo-X-Prime™ bispecific antibody targeting CD40 and CEACAM5, induces tumor localized immune cell activation in preclinical in vivo tumor model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5309.

Phase I Trial of Viral Vector-Based Personalized Vaccination Elicits Robust Neoantigen-Specific Antitumor T-Cell Responses.

Personalized vaccines targeting multiple neoantigens (nAgs) are a promising strategy for eliciting a diversified antitumor T-cell response to overcome tumor heterogeneity. NOUS-PEV is a vector-based personalized vaccine, expressing 60 nAgs and consists of priming with a nonhuman Great Ape Adenoviral vector (GAd20) followed by boosts with Modified Vaccinia Ankara. Here, we report data of a phase Ib trial of NOUS-PEV in combination with pembrolizumab in treatment-naïve patients with metastatic melanoma (NCT04990479). The feasibility of this approach was demonstrated by producing, releasing, and administering to 6 patients 11 of 12 vaccines within 8 weeks from biopsy collection to GAd20 administration. The regimen was safe, with no treatment-related serious adverse events observed and mild vaccine-related reactions. Vaccine immunogenicity was demonstrated in all evaluable patients receiving the prime/boost regimen, with detection of robust neoantigen-specific immune responses to multiple neoantigens comprising both CD4 and CD8 T cells. Expansion and diversification of vaccine-induced T-cell receptor (TCR) clonotypes was observed in the posttreatment biopsies of patients with clinical response, providing evidence of tumor infiltration by vaccine-induced neoantigen-specific T cells. These findings indicate the ability of NOUS-PEV to amplify and broaden the repertoire of tumor-reactive T cells to empower a diverse, potent, and durable antitumor immune response. Finally, a gene signature indicative of the reduced presence of activated T cells together with very poor expression of the antigen-processing machinery genes has been identified in pretreatment biopsies as a potential biomarker of resistance to the treatment.

Abstract B017: NINJA PDAC: A robust murine pancreatic cancer organoid transplant model with inducible neoantigens for studying tumor microenvironment interactions with anti-tumor T-cell immunity

Abstract Pancreatic ductal adenocarcinoma (PDAC) is highly lethal due to early metastasis and poor therapeutic response including to anti-PD1/CTLA4-based immunotherapy, characteristics attributed to a desmoplastic tumor microenvironment (TME) and low immunogenicity. However, long-term human PDAC survivors exhibit higher neoantigen expression with active T-cell immunogenicity, and most human PDAC express predicted neoepitopes, arguing that T-cell mediated anti-tumor immunity shapes PDAC progression. By contrast, tumors in classical pre-clinical (KRASLSL-G12D; TRP53F/F; pancreas-specific Cre, or KPC) murine models exhibit low neoantigen burden, are non-immunogenic, with growth kinetics independent of T cells, making them poorly suited to study T-cell immunity. Combined chemoimmunotherapy regimens for human PDAC might be developed more efficiently via preclinical studies in murine models with physiologic stroma, defined neoantigens that can be induced in established tumors, and measurable neoantigen-specific T-cell responses. We developed NINJA PDAC, a novel, robust transplantable murine pancreatic cancer organoid model, to study neoantigen-specific anti-tumor T-cell responses and how they are influenced by the TME. The NINJA (Damo et al., 2021) system allows for spatially (Cre) and temporally (doxycycline+tamoxifen) controlled inducible expression of LCMV-derived neoantigens with low-to-moderate MHCI/II-binding affinity (GP33 and GP66, respectively) comparable to human PDAC, in Kras-mutated, p53-deficient PDAC organoids. Transplanted NINJA PDAC organoids engraft robustly both subcutaneously and orthotopically in syngeneic mice, with reproducible kinetics. Unlike 2D cell line transplants, these organoid-derived tumors have a complex ductal architecture, immune islands, and fibrotic stroma more representative of human PDAC. T-cell depletion studies demonstrated that full rejection of tumors with constitutive neoantigen expression (NINJA ‘ON’) requires both CD4+ and CD8+ neoantigen-specific T-cells, allowing the study of the roles of both helper and cytotoxic T-cells in anti-PDAC immunity. ‘Poised’ NINJA PDAC organoids do not express neoantigen until induction, and we confirmed high tumor neoantigen expression can be induced with doxycycline/tamoxifen in vivo (38%±18% neoantigen-expressing tumor cells). Early induction in vivo leads to intratumoral CD3+ T-cell infiltration, with increased neoantigen-specific (H2Db/gp33-41-tetramer positive) T-cells in tumors and tumor-draining lymph nodes. Late induction in vivo leads to neoantigen induction, but more muted T-cell infiltration and minimally attenuated tumor growth, suggesting a role of an established TME in suppressing T-cell responses. NINJA PDAC is a promising model that affords a high-fidelity toolset to study how murine neoantigen-specific anti-tumor T-cell responses are perturbed by the TME and further altered by host variables (such as obesity) that modulate the TME with the potential to expedite the development of new combination immunotherapies. Citation Format: Jeremy B. Jacox, Gena G. Foster, Dhruvi Shah, Nikhil S. Joshi, Mandar D. Muzumdar. NINJA PDAC: A robust murine pancreatic cancer organoid transplant model with inducible neoantigens for studying tumor microenvironment interactions with anti-tumor T-cell immunity [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B017.

Programming peptide-oligonucleotide nano-assembly for engineering of neoantigen vaccine with potent immunogenicity.

Background: Neoantigen nanovaccine has been recognized as a promising treatment modality for personalized cancer immunotherapy. However, most current nanovaccines are carrier-dependent and the manufacturing process is complicated, resulting in potential safety concerns and suboptimal codelivery of neoantigens and adjuvants to antigen-presenting cells (APCs). Methods: Here we report a facile and general methodology for nanoassembly of peptide and oligonucleotide by programming neoantigen peptide with a short cationic module at N-terminus to prepare nanovaccine. The programmed peptide can co-assemble with CpG oligonucleotide (TLR9 agonist) into monodispersed nanostructures without the introduction of artificial carrier. Results: We demonstrate that the engineered nanovaccine promoted the codelivery of neoantigen peptides and adjuvants to lymph node-residing APCs and instigated potent neoantigen-specific T-cell responses, eliciting neoantigen-specific antitumor immune responses with negligible systemic toxicity. Furthermore, the antitumor T-cell immunity is profoundly potentiated when combined with anti-PD-1 therapy, leading to significant inhibition or even complete regression of established melanoma and MC-38 colon tumors. Conclusions: Collectively, this work demonstrates the feasibility and effectiveness of personalized cancer nanovaccine preparation with high immunogenicity and good biosafety by programming neoantigen peptide for nanoassembly with oligonucleotides without the aid of artificial carrier.

Phenotypic signatures of circulating neoantigen-reactive CD8+ T cells in patients with metastatic cancers

Circulating Tcells from peripheral blood (PBL) can provide a rich and noninvasive source for antitumor Tcells. By single-cell transcriptomic profiling of 36 neoantigen-specific Tcell clones from 6 metastatic cancer patients, we report the transcriptional and cell surface signatures of antitumor PBL-derived CD8+ Tcells (NeoTCRPBL). Comparison of tumor-infiltrating lymphocyte (TIL)- and PBL-neoantigen-specific Tcells revealed that NeoTCRPBL Tcells are low in frequency and display less-dysfunctional memory phenotypes relative to their TIL counterparts. Analysis of 100 antitumor TCR clonotypes indicates that most NeoTCRPBL populations target the same neoantigens as TILs. However, NeoTCRPBL TCR repertoire is only partially shared with TIL. Prediction and testing of NeoTCRPBL signature-derived TCRs from PBL of 6 prospective patients demonstrate high enrichment of clonotypes targeting tumor mutations, a viral oncogene, and patient-derived tumor. Thus, the NeoTCRPBL signature provides an alternative source for identifying antitumor Tcells from PBL of cancer patients, enabling immune monitoring and immunotherapies.

Spleen-targeted neoantigen DNA vaccine forpersonalized immunotherapy of hepatocellularcarcinoma.

Neoantigens are emerging as attractive targets to develop personalized cancer vaccines, but their immunization efficacy is severely hampered by their restricted accessibility to lymphoid tissues where immune responses are initiated. Leveraging the capability of red blood cells (RBCs) to capture and present pathogens in peripheral blood to the antigen-presenting cells (APCs) in spleen, we developed a RBC-driven spleen targeting strategy to deliver DNA vaccine encoding hepatocellular carcinoma (HCC) neoantigen. The DNA vaccine-encapsulating polymeric nanoparticles that were intentionally hitchhiked on the preisolated RBCs could preferentially accumulate in the spleen to promote the neoantigen expression by APCs, resulting in the burst of neoantigen-specific T-cell immunity to prevent tumorigenesis in a personalized manner, and slow down tumor growth in the established aggressively growing HCC. Remarkably, when combined with anti-PD-1, the vaccine achieved complete tumor regression and generated a robust systemic immune response with long-term tumor-specific immunological memory, which thoroughly prevented tumor recurrence and spontaneous lung metastasis. This study offers a prospective strategy to develop personalized neoantigen vaccines for augmenting cancer immunotherapy efficiency in immune "cold" HCC.

Detection of mutant antigen-specific T cell receptors against multiple myeloma for T cell engineering

Multiple myeloma (MM) remains an incurable hematological neoplasm. Neoantigen-specific Tcell receptor (TCR)-engineered T(TCR-T) cell therapy is a potential alternative treatment. Particularly, TCRs derived from a third-party donor may cover broad ranges of neoantigens, whereas TCRs in patients suffering from immune disorders are limited. However, the efficacy and feasibility of treating MM have not been evaluated thoroughly. In this study, we established a system for identifying immunogenic mutant antigens on MM cells and their corresponding TCRs using healthy donor-derived peripheral blood mononuclear cells (PBMCs). Initially, the immune responses to 35 candidate peptides predicted by the immunogenomic analysis were investigated. Peptide-reactive T lymphocytes were enriched, and subsequently, TCR repertoires were determined by single-cell TCR sequencing. Eleven reconstituted TCRs showed mutation-specific responses against 4 peptides. Particularly, we verified the HLA-A∗24:02-binding QYSPVQATF peptide derived from COASY S55Y as the naturally processed epitope across MM cells, making it a promising immune target. Corresponding TCRs specifically recognized COASY S55Y+HLA-A∗24:02+ MM cells and augmented tumoricidal activity. Finally, adoptive cell transfer of TCR-T cells showed objective responses in the xenograft model. We initiatively proposed the utility of tumor mutated antigen-specific TCR genes to suppress MM. Our unique strategy will facilitate further identification of neoantigen-specific TCRs.

A Sampling of Highlights from the Literature.

What We're Reading| May 03 2023 A Sampling of Highlights from the Literature: Article Recommendations from Our Deputy and Senior Editors Author & Article Information Online ISSN: 2326-6074 Print ISSN: 2326-6066 ©2023 American Association for Cancer Research2023American Association for Cancer Research Cancer Immunol Res (2023) 11 (5): 557. https://doi.org/10.1158/2326-6066.CIR-11-5-WWR Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Cite Icon Cite Search Site Article Versions Icon Versions Version of Record May 3 2023 Citation A Sampling of Highlights from the Literature: Article Recommendations from Our Deputy and Senior Editors. Cancer Immunol Res 1 May 2023; 11 (5): 557. https://doi.org/10.1158/2326-6066.CIR-11-5-WWR Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest Search Advanced Search Polyclonal neoantigen-specific T-cell responses associate with anti–PD-1 benefit (from Alex Ritter, Jennifer Lippincott Schwartz and Gillian Griffiths via NIH Flickr) To better understand differences in the immune response in patients with metastatic melanoma who do and do not have a clinical response to anti–PD-1 therapy, Puig-Saus et al. generated neoantigen-specific T cells from 11 patients using personalized neoantigen peptide–HLA libraries. Responding and nonresponding patients had neoantigen-specific CD8+ T cells in peripheral blood and tumor that recognized a limited number of mutations, but the CD8+ T cells from those who responded to therapy were more polyclonal, with multiple neoantigen-specific T-cell receptor clonotypes for the mutations, and were detected longitudinally, highlighting important immune characteristics of a successful clinical response to anti–PD-1 therapy. Puig-Saus C, …, Ribas A. Nature 2023 March 8;615:697–704. Neutrophils have a key role in tumor control following immunotherapy (from SVG) Neutrophils can have both pro- and... You do not currently have access to this content.

OncoVEXmGM-CSFexpands tumor antigen-specific CD8+ T-cell response in preclinical models

BackgroundCheckpoint inhibitors targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) have demonstrated clinical efficacy in advanced melanoma, but only a...

Cell surface marker-based capture of neoantigen-reactive CD8+ T-cell receptors from metastatic tumor digests

BackgroundCellular immunotherapies using autologous tumor-infiltrating lymphocytes (TIL) can induce durable regression of epithelial cancers in selected patients with treatment-refractory metastatic disease. As the genetic engineering of T cells with tumor-reactive...

Abstract LB199: A personalized neoantigen vaccine is well tolerated and induces specific T-cell immune response in patients with resected melanoma

Abstract Tumor mutations giving rise to neoantigens have recently emerged as promising targets for cancer immunotherapy. Vaccines delivering tumor-specific neoantigens have demonstrated favorable efficacy and safety results in numerous preclinical and early clinical studies. However, selecting therapeutically relevant neoantigens amongst the myriad of cancer mutations has proven challenging. To overcome this, we have developed a proprietary AI-based target discovery platform, PIONEER, with enhanced predictive performance and increased precision. The PIONEER top-ranked neoantigens were selected and included in the personalized DNA vaccine candidate EVX-02. To assess the ability of the PIONEER designed neoantigen vaccine candidate to induce neoantigen immunogenicity and anti-tumor effect in preclinical models, mice were immunized with a mouse surrogate EVX-02 molecule, mEVX-02. mEVX-02 vaccination completely prevented establishment of tumors and induced neoantigen-specific, polyfunctional CD4+ and CD8+ T cells in the blood and spleen of immunized mice. An enhanced antitumor effect was obtained when combining mEVX-02 with anti-PD-1 mAb treatment. Encouraged by the preclinical results, we conducted a first-in-human multicenter Phase I clinical study of EVX-02 in combination with nivolumab in patients with resected malignant melanoma. The objectives of the trial were to investigate safety and tolerability, operational and clinical feasibility, and immunogenicity of the applied personal neoantigens. Each patient received a fully personalized drug that was produced in a complex process, from biopsy, through genome sequencing, AI-profiling, vaccine design, manufacturing, quality testing, and drug product release. This was succeeded with every single step for each patient. In all patients, EVX-02 treatment was well tolerated, and only very mild adverse events (AEs) have been observed in relation to immunization with EVX-02. Interim data demonstrated neoantigen-specific T-cell immune responses upon EVX-02 treatment and that the responses were mediated by activated CD4+ and CD8+ T cells. The measured T-cell responses were robust and long lasting. Together, these findings validate the precision and predictive power of our proprietary AI platform, PIONEER, and provide proof of mechanism for the DNA-delivery technology in that the encoded neoantigens gave rise to significant immune reactions. Citation Format: Daniela Kleine-Kohlbrecher, Nadia Viborg Petersen, Michail Angelos Pavlidis, Thomas Trolle, Stine Friis, Jens Kringelum, Anders Bundgaard Soerensen, Thomas Strandet Jepsen, Camilla Højgaard, Anders Jespersen, Erik D. Heegaard, Britt Winding Lauenborg, Birgitte Rønø. A personalized neoantigen vaccine is well tolerated and induces specific T-cell immune response in patients with resected melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB199.

Towards next‐generation TIL therapy: TILs enriched in neoepitope‐specific T cells

Towards next‐generation TIL therapy: TILs enriched in neoepitope‐specific T cells

Personalized TCR T Cells Enabled by CRISPR.

A 16-person trial demonstrated the feasibility and safety of using CRISPR gene editing to create personalized T-cell therapies equipped with neoantigen-specific T-cell receptors. However, the elaborate manufacturing process and limited efficacy of the engineered cells have prompted the therapy's sponsor to pursue other strategies.

Fast track to personalized TCR Tcell therapies.

In this issue of Cancer Cell, Hanada etal. leverage single-cell multi-omics of lung cancer resident lymphocytes to identify phenotypic and transcriptomic signatures differentially expressed by neoantigen-reactive clonotypes. These findings could substantially expedite the selection of neoantigen-specific Tcell receptors (TCRs) for individualized Tcell therapies.

Combination Neoantigen-Based Dendritic Cell Vaccination and Adoptive T-Cell Transfer Induces Antitumor Responses Against Recurrence of Hepatocellular Carcinoma.

A high rate of recurrence after curative therapy is a major challenge for the management of hepatocellular carcinoma (HCC). Currently, no effective adjuvant therapy is available to prevent HCC recurrence. We designed a personalized neoantigen-loaded dendritic cell vaccine and neoantigen-activated T-cell therapy, and used it as adjuvant therapy to treat 10 patients with HCC who had undergone curative resection or radiofrequency ablation in the first stage of a phase II trial (NCT03067493). The primary outcomes were safety and neoantigen-specific immune response. Disease-free survival (DFS) was also evaluated. The immunotherapy was successfully administered to all the patients without unexpected delay and demonstrated a reasonable safety profile with no grade ≥3 treatment-related side effects reported. Seventy percent of patients generated de novo circulating multiclonal neoantigen-specific T-cell responses. Induced neoantigen-specific immunity was maintained over time, and epitope spreading was observed. Patients who generated immune responses to treatment exhibited prolonged DFS compared with nonresponders (P = 0.012), with 71.4% experiencing no relapse for 2 years after curative treatment. High expression of an immune stimulatory signature, enhanced immune-cell infiltration (i.e., CD8+ T cells), and upregulated expression of T-cell inflammatory gene profiles were found in the primary tumors of the responders. In addition, neoantigen depletion (immunoediting) was present in the recurrent tumors compared with the primary tumors (7/9 vs. 1/17, P = 0.014), suggesting that immune evasion occurred under the pressure of immunotherapy. Our study indicates that neoantigen-based combination immunotherapy is feasible, safe, and has the potential to reduce HCC recurrence after curative treatment.

Functional analysis of peripheral and intratumoral neoantigen-specific TCRs identified in a patient with melanoma

BackgroundNeoantigens derived from somatic mutations correlate with therapeutic responses mediated by treatment with immune checkpoint inhibitors. Neoantigens are therefore highly attractive targets for the development of therapeutic approaches in personalized...