scholarly journals Phase I/II trial of a long peptide vaccine (LPV7) plus toll-like receptor (TLR) agonists with or without incomplete Freund’s adjuvant (IFA) for resected high-risk melanoma

2021 ◽  
Vol 9 (8) ◽  
pp. e003220
Author(s):  
Sapna P Patel ◽  
Gina R Petroni ◽  
Jason Roszik ◽  
Walter C Olson ◽  
Nolan A Wages ◽  
...  
Keyword(s):  
T Cell ◽  
Adaptive Design ◽  
Ex Vivo ◽  
Peptide Vaccine ◽  
T Cell Responses ◽  
Tlr Agonists ◽  
Cell Responses ◽  
Incomplete Freund’S Adjuvant ◽  
Freund’S Adjuvant ◽  
Freund's Adjuvant

BackgroundWe performed a clinical trial to evaluate safety and immunogenicity of a novel long peptide vaccine administered in combinations of incomplete Freund’s adjuvant (IFA) and agonists for TLR3 (polyICLC) and TLR7/8 (resiquimod). We hypothesized that T cell responses to minimal epitope peptides (MEPs) within the long peptides would be enhanced compared with prior vaccines with MEP themselves and that T cell responses would be enhanced with TLR agonists, compared with IFA alone.MethodsParticipants with resected stage IIB-IV melanoma were vaccinated with seven long melanoma peptides (LPV7) from tyrosinase, gp100, MAGE-A1, MAGE-A10, and NY-ESO-1, each containing a known MEP for CD8+ T cells, plus a tetanus helper peptide (Tet) restricted by Class II MHC. Enrollment was guided by an adaptive design to one of seven adjuvant combinations. Vaccines were administered at weeks 1, 2, 3, 6, 9, 12 at rotating injection sites. T cell and IgG antibody (Ab) responses were measured with IFN-gamma ELIspot assay ex vivo and ELISA, respectively.ResultsFifty eligible participants were assigned to seven study groups, with highest enrollment on arm E (LPV7+Tet+IFA+polyICLC). There was one dose-limiting toxicity (DLT) in Group E (grade 3 injection site reaction, 6% DLT rate). All other treatment-related adverse events were grades 1–2. The CD8+ T cell immune response rate (IRR) to MEPs was 18%, less than in prior studies using MEP vaccines in IFA. The CD8+ T cell IRR trended higher for IFA-containing adjuvants (24%) than adjuvants containing only TLR agonists (6%). Overall T cell IRR to full-length LPV7 was 30%; CD4+ T cell IRR to Tet was 40%, and serum Ab IRR to LPV7 was 84%. These IRRs also trended higher for IFA-containing adjuvants (36% vs 18%, 48% vs 24%, and 97% vs 60%, respectively).ConclusionsThe LPV7 vaccine is safe with each of seven adjuvant strategies and induced T cell responses to CD8 MEPs ex vivo in a subset of patients but did not enhance IRRs compared with prior vaccines using short peptides. Immunogenicity was supported more by IFA than by TLR agonists alone and may be enhanced by polyICLC plus IFA.Trial registration numberNCT02126579.

scholarly journals Trial to evaluate the immunogenicity and safety of a melanoma helper peptide vaccine plus incomplete Freund’s adjuvant, cyclophosphamide, and polyICLC (Mel63)

2021 ◽  
Vol 9 (1) ◽  
pp. e000934
Author(s):  
Craig L Slingluff, Jr. ◽  
Gina R Petroni ◽  
Kimberly A Chianese-Bullock ◽  
Nolan A Wages ◽  
Walter C Olson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adaptive Design ◽  
Ex Vivo ◽  
Peptide Vaccine ◽  
T Cell Responses ◽  
Cell Responses ◽  
Incomplete Freund’S Adjuvant ◽  
Freund’S Adjuvant ◽  
Freund's Adjuvant

BackgroundPeptide vaccines designed to stimulate melanoma-reactive CD4+ T cells can induce T cell and antibody (Ab) responses, associated with enhanced overall survival. We hypothesized that adding toll-like receptor 3 agonist polyICLC to an incomplete Freund’s adjuvant (IFA) would be safe and would support strong, durable CD4+ T cell and Ab responses. We also hypothesized that oral low-dose metronomic cyclophosphamide (mCy) would be safe, would reduce circulating regulatory T cells (T-regs) and would further enhance immunogenicity.Participants and methodsAn adaptive design based on toxicity and durable CD4+ T cell immune response (dRsp) was used to assign participants with resected stage IIA-IV melanoma to one of four study regimens. The regimens included a vaccine comprising six melanoma peptides restricted by Class II MHC (6MHP) in an emulsion with IFA alone (Arm A), with IFA plus systemic mCy (Arm B), with IFA+ local polyICLC (Arm C), or with IFA+ polyICLC+ mCy (Arm D). Toxicities were recorded (CTCAE V.4.03). T cell responses were measured by interferon γ ELIspot assay ex vivo. Serum Ab responses to 6MHP were measured by ELISA. Circulating T-regs were assessed by flow cytometry.ResultsForty-eight eligible participants were enrolled and treated. Early data on safety and dRsp favored enrollment on arm D. Total enrollment on Arms A-D were 3, 7, 6, and 32, respectively. Treatment-related dose-limiting toxicities (DLTs) were observed in 1/7 (14%) participants on arm B and 2/32 (6%) on arm D. None exceeded the 25% DLT threshold for early closure to enrollment for any arm. Strong durable T cell responses to 6MHP were detected ex vivo in 0%, 29%, 67%, and 47% of participants on arms A-D, respectively. IgG Ab responses were greatest for arms C and D. Circulating T-regs frequencies were not altered by mCy.Conclusions6MHP vaccines administered with IFA, polyICLC, and mCy were well tolerated. The dRsp rate for arm D of 47% (90% CI 32 to 63) exceeded the 18% (90% CI 11 to 26) rate previously observed with 6MHP in IFA alone. Vaccination with IFA+ polyICLC (arm C) also showed promise for enhancing T cell and Ab responses.

scholarly journals Peptide vaccine candidate mimics the heterogeneity of natural SARS-CoV-2 immunity in convalescent humans and induces broad T cell responses in mice models

2020 ◽  
Author(s):  
Eszter Somogyi ◽  
Zsolt Csiszovszki ◽  
Levente Molnár ◽  
Orsolya Lőrincz ◽  
József Tóth ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Peptide Vaccine ◽  
T Cell Responses ◽  
Hla Class I ◽  
Class I ◽  
Structural Proteins ◽  
Cell Repertoire ◽  
Cell Responses

AbstractWe developed a global peptide vaccine against SARS-CoV-2 that addresses the dual challenges of heterogeneity in the immune responses of different individuals and potential heterogeneity of the infecting virus. PolyPEPI-SCoV-2 is a polypeptide vaccine containing nine 30-mer peptides derived from all four major structural proteins of the SARS-CoV-2. Vaccine peptides were selected based on their frequency as HLA class I and class II personal epitopes (PEPIs) restricted to multiple autologous HLA alleles of individuals in an in silico cohort of 433 subjects of different ethnicities. PolyPEPI-SCoV-2 vaccine administered with Montanide ISA 51VG adjuvant generated robust, Th1-biased CD8+ and CD4+ T cell responses against all four structural proteins of the virus, as well as binding antibodies upon subcutaneous injection into BALB/c and CD34+ transgenic mice. In addition, PolyPEPI-SCoV-2-specific, polyfunctional CD8+ and CD4+ T cells were detected ex vivo in each of the 17 asymptomatic/mild COVID-19 convalescents’ blood investigated, 1–5 months after symptom onset. The PolyPEPI-SCoV-2-specific T cell repertoire used for recovery from COVID-19 was extremely diverse: donors had an average of seven different peptide-specific T cells, against the SARS-CoV-2 proteins; 87% of donors had multiple targets against at least three SARS-CoV-2 proteins and 53% against all four. In addition, PEPIs determined based on the complete HLA class I genotype of the convalescent donors were validated, with 84% accuracy, to predict PEPI-specific CD8+ T cell responses measured for the individuals. Extrapolation of the above findings to a US bone marrow donor cohort of 16,000 HLA-genotyped individuals with 16 different ethnicities (n=1,000 each ethnic group) suggest that PolyPEPI-SCoV-2 vaccination in a general population will likely elicit broad, multi-antigenic CD8+ and CD4+ T cell responses in 98% of individuals, independent of ethnicity, including Black, Asian, and Minority Ethnic (BAME) cohorts.

scholarly journals 413 GEN-009, a personalized neoantigen vaccine, elicits robust immune responses in individuals with advanced or metastatic solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A438-A438
Author(s):  
Mara Shainheit ◽  
Devin Champagne ◽  
Gabriella Santone ◽  
Syukri Shukor ◽  
Ece Bicak ◽  
...  
Keyword(s):  
Clinical Trial ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Solid Tumors ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Checkpoint Blockade ◽  
T Cell Subsets ◽  
Cell Responses

BackgroundATLASTM is a cell-based bioassay that utilizes a cancer patient‘s own monocyte-derived dendritic cells and CD4+ and CD8+ T cells to screen their mutanome and identify neoantigens that elicit robust anti-tumor T cell responses, as well as, deleterious InhibigensTM.1 GEN-009, a personalized vaccine comprised of 4–20 ATLAS-identified neoantigens combined with Hiltonol®, harnesses the power of neoantigen-specific T cells to treat individuals with solid tumors. The safety and efficacy of GEN-009 is being assessed in a phase 1/2a clinical trial (NCT03633110).MethodsA cohort of 15 adults with solid tumors were enrolled in the study. During the screening period, patients received standard of care PD-1-based immunotherapies appropriate for their tumor type. Subsequently, patients were immunized with GEN-009 with additional doses administered at 3, 6, 12, and 24 weeks. Peripheral blood mononuclear cells (PBMCs) were collected at baseline, pre-vaccination (D1), as well as 29, 50, 92, and 176 days post first dose. Vaccine-induced immunogenicity and persistence were assessed by quantifying neoantigen-specific T cell responses in ex vivo and in vitro stimulation dual-analyte fluorospot assays. Polyfunctionality of neoantigen-specific T cells was evaluated by intracellular cytokine staining. Additionally, potential correlations between the ATLAS-identified profile and vaccine-induced immunogenicity were assessed.ResultsGEN-009 augmented T cell responses in 100% of evaluated patients, attributable to vaccine and not checkpoint blockade. Furthermore, neoantigen-induced secretion of IFNγ and/or TNFα by PBMCs, CD4+, and CD8+ T cells was observed in all patients. Responses were primarily from polyfunctional TEM cells and detectable in both CD4+ and CD8+ T cell subsets. Some patients had evidence of epitope spreading. Unique response patterns were observed for each patient with no apparent relationship between tumor types and time to emergence, magnitude or persistence of response. Ex vivo vaccine-induced immune responses were observed as early as 1 month, and in some cases, persisted for 176 days. Clinical efficacy possibly attributable to GEN-009 was observed in several patients, but no correlation has yet been identified with neoantigen number or magnitude of immune response.ConclusionsATLAS empirically identifies stimulatory neoantigens using the patient‘s own immune cells. GEN-009, which is comprised of personalized, ATLAS-identified neoantigens, elicits early, long-lasting and polyfunctional neoantigen-specific CD4+ and CD8+ T cell responses in individuals with advanced cancer. Several patients achieved clinical responses that were possibly attributable to vaccine; efforts are underway to explore T cell correlates of protection. These data support that GEN-009, in combination with checkpoint blockade, represents a unique approach to treat solid tumors.AcknowledgementsWe are grateful to the patients and their families who consented to participate in the GEN-009-101 clinical trial.Trial RegistrationNCT03633110Ethics ApprovalThis study was approved by Western Institutional Review Board, approval number 1-1078861-1. All subjects contributing samples provided signed individual informed consent.ReferenceDeVault V, Starobinets H, Adhikari S, Singh S, Rinaldi S, Classon B, Flechtner J, Lam H. Inhibigens, personal neoantigens that drive suppressive T cell responses, abrogate protection of therapeutic anti-tumor vaccines. J. Immunol 2020; 204(1 Supplement):91.15.

scholarly journals Characterisation of CD154+ T cells following ex vivo allergen stimulation illustrates distinct T cell responses to seasonal and perennial allergens in allergic and non-allergic individuals

2013 ◽  
Vol 14 (1) ◽  
pp. 49 ◽  
Author(s):  
Karen A Smith ◽  
Nicola J Gray ◽  
Femi Saleh ◽  
Elizabeth Cheek ◽  
Anthony J Frew ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Cell Responses ◽  
Perennial Allergens

scholarly journals 153 NEO-PTC-01 (BNT-221), an autologous neoantigen-specific T-cell product for adoptive cell therapy of metastatic melanoma

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A167-A167
Author(s):  
Divya Lenkala ◽  
Jessica Kohler ◽  
Brian McCarthy ◽  
Michael Nelson ◽  
Jonathan McGee ◽  
...  
Keyword(s):  
T Cell ◽  
Metastatic Melanoma ◽  
Ex Vivo ◽  
Adoptive Cell Therapy ◽  
T Cell Responses ◽  
Process Engineering ◽  
High Quality ◽  
Cell Product ◽  
Cell Responses ◽  
Melanoma Patients

BackgroundNeoantigens are tumor-specific antigens that are important in the anti-tumor immune response. These antigens are not subject to central immune tolerance and are therefore potentially more immunogenic than tumor-associated antigens. NEO-STIM®, our propriety ex vivo induction process, was developed to generate T-cell products specific to these neoantigens from the peripheral blood of patient. Here, we present the results of a proof of concept, pre-clinical study with multiple successful process engineering runs generating a neoantigen-specific T-cell product (NEO-PTC-01) using leukaphereses from metastatic melanoma patients. These products contain specific T-cell responses targeting multiple neoantigens from each individual patient‘s tumor.MethodsPatient-specific neoantigens were predicted using our RECON® bioinformatics platform. Predicted high-quality neoantigens were utilized in our ex vivo stimulation protocol, NEO-STIM, in the process engineering runs of NEO-PTC-01. NEO-STIM is used to prime, activate and expand memory and de novo T-cell responses from both the CD4+ and the CD8+ compartment. High throughput flow cytometric analysis was performed to characterize the specificity and functionality (cytokine production and cytolytic capacity) of the induced T-cell responses.ResultsHere we present the successful induction of 4–5 CD8+ and 4–7 CD4+ T-cell responses per patient, generated using peripheral blood mononuclear cells from multiple melanoma patients during these successful process engineering runs. We then extensively characterized these T-cell responses and demonstrate that these responses are functional, specific and have cytolytic capacity. Moreover, the induced T cells can recognize autologous tumor.ConclusionsNEO-STIM is a novel platform that generates ex vivo T-cell responses to high-quality neoantigen targets. NEO-PTC-01, the neoantigen-specific T cell product generated from this process, is a potent adoptive cell therapy targeting multiple immunogenic neoantigens in patients with metastatic melanoma.

scholarly journals Analysis of CD4+ T-Cell Responses to Human Papillomavirus (HPV) Type 11 L1 in Healthy Adults Reveals a High Degree of Responsiveness and Cross-Reactivity with Other HPV Types

2002 ◽  
Vol 76 (15) ◽  
pp. 7418-7429 ◽  
Author(s):  
O. Martin Williams ◽  
Keith W. Hart ◽  
Eddie C. Y. Wang ◽  
Colin M. Gelder
Keyword(s):  
Human Papillomavirus ◽  
T Cell ◽  
In Vitro Selection ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Cross Reactivity ◽  
Peripheral Blood Mononuclear ◽  
Cell Responses ◽  
Hpv Types

ABSTRACT Human papillomavirus type 11 (HPV-11) infection causes genital warts and recurrent respiratory papillomatosis. While there is compelling evidence that CD4+ T cells play an important role in immune surveillance of HPV-associated diseases, little is known about human CD4+ T-cell recognition of HPV-11. We have investigated the CD4+ T-cell responses of 25 unrelated healthy donors to HPV-11 L1 virus-like particles (VLP). CD4+ T-cell lines from 21 of 25 donors were established. Cell sorting experiments carried out on cells from six donors demonstrated that the response was located in the CD45RAlow CD45ROhigh memory T-cell population. To determine the peptide specificity of these responses, epitope selection was analyzed by using 95 15-mer peptides spanning the entire HPV-11 L1 protein. No single region of L1 was immunodominant; responders recognized between 1 and 10 peptides, located throughout the protein, and peptide responses fell into clear HLA class II restricted patterns. Panels of L1 peptides specific for skin and genital HPV were used to show that the L1 CD4+ T-cell responses were cross-reactive. The degree of cross-reactivity was inversely related to the degree of L1 sequence diversity between these viruses. Finally, responses to HPV-11 L1 peptides were elicited from ex vivo CD45RO+ peripheral blood mononuclear cells, demonstrating that recognition of HPV-11 was a specific memory response and not due to in vitro selection during tissue culture. This is the first study of CD4+ T-cell responses to HPV-11 in healthy subjects and demonstrates marked cross-reactivity with other skin and genital HPV types. This cross-reactivity may be of significance for vaccine strategies against HPV-associated clinical diseases.

scholarly journals Novel Recombinant Mycobacterium bovis BCG, Ovine Atadenovirus, and Modified Vaccinia Virus Ankara Vaccines Combine To Induce Robust Human Immunodeficiency Virus-Specific CD4 and CD8 T-Cell Responses in Rhesus Macaques

2010 ◽  
Vol 84 (12) ◽  
pp. 5898-5908 ◽  
Author(s):  
Maximillian Rosario ◽  
Richard Hopkins ◽  
John Fulkerson ◽  
Nicola Borthwick ◽  
Máire F. Quigley ◽  
...  
Keyword(s):  
T Cell ◽  
Vaccinia Virus ◽  
Mycobacterium Bovis ◽  
Ex Vivo ◽  
Rhesus Macaques ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Modified Vaccinia Virus Ankara ◽  
Hiv 1

ABSTRACT Mycobacterium bovis bacillus Calmette-Guérin (BCG), which elicits a degree of protective immunity against tuberculosis, is the most widely used vaccine in the world. Due to its persistence and immunogenicity, BCG has been proposed as a vector for vaccines against other infections, including HIV-1. BCG has a very good safety record, although it can cause disseminated disease in immunocompromised individuals. Here, we constructed a recombinant BCG vector expressing HIV-1 clade A-derived immunogen HIVA using the recently described safer and more immunogenic BCG strain AERAS-401 as the parental mycobacterium. Using routine ex vivo T-cell assays, BCG.HIVA401 as a stand-alone vaccine induced undetectable and weak CD8 T-cell responses in BALB/c mice and rhesus macaques, respectively. However, when BCG.HIVA401 was used as a priming component in heterologous vaccination regimens together with recombinant modified vaccinia virus Ankara-vectored MVA.HIVA and ovine atadenovirus-vectored OAdV.HIVA vaccines, robust HIV-1-specific T-cell responses were elicited. These high-frequency T-cell responses were broadly directed and capable of proliferation in response to recall antigen. Furthermore, multiple antigen-specific T-cell clonotypes were efficiently recruited into the memory pool. These desirable features are thought to be associated with good control of HIV-1 infection. In addition, strong and persistent T-cell responses specific for the BCG-derived purified protein derivative (PPD) antigen were induced. This work is the first demonstration of immunogenicity for two novel vaccine vectors and the corresponding candidate HIV-1 vaccines BCG.HIVA401 and OAdV.HIVA in nonhuman primates. These results strongly support their further exploration.

scholarly journals 248 Empiric profiling of peripheral T cell recall responses to tumor mutanomes versus in silico predictions in NSCLC patients undergoing pembrolizumab treatment ± chemotherapy

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A268-A268
Author(s):  
Madison Milaszewski ◽  
James Loizeaux ◽  
Emily Tjon ◽  
Crystal Cabral ◽  
Tulin Dadali ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Combination Therapy ◽  
In Silico ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Patient Specific ◽  
In Silico Prediction ◽  
Cell Responses ◽  
In Silico Predictions

BackgroundEffective immune checkpoint blockade (ICB) treatment is dependent on T-cell recognition of patient-specific mutations (neoantigens). Empirical identification of neoantigens ex vivo has revealed shortcomings of in silico predictions.1 To better understand the impact of ICB treatment on T cell responses and differences between in silico and in vitro methods, neoantigen-specific T cell responses were evaluated in patients with non-small cell lung cancer undergoing first-line therapy with pembrolizumab ± chemotherapy.MethodsTumor and whole blood samples were collected from 14 patients prior to and after immunotherapy; seven each in monotherapy and combination therapy cohorts. The ex vivo ATLAS™ platform was used to profile neoantigen-specific T-cell responses. Patient-specific tumor mutations identified by next-generation sequencing (NGS) were expressed individually as ATLAS clones, processed patient-specific autologous antigen presenting cells, and presented to their T cells in vitro. ATLAS-verified antigens were compared with epitope predictions made using algorithms.ResultsOn average, 150 (range 37–339) non-synonymous mutations were identified. Pre-treatment, ATLAS identified T cell responses to a median of 15% (9–25%) of mutations, with nearly equal proportions of neoantigens (8%, 5–15%) and Inhibigens™, targets of suppressive T cell responses (8%, 3–13%). The combination therapy cohort had more confirmed neoantigens (46, 20–103) than the monotherapy cohort (7, 6–79). After treatment, the median ratio of CD4:CD8 T cells doubled in the monotherapy but not combination cohort (1.2 to 2.4 v. 1.6 to 1.3). Upon non-specific stimulation, T cells from patients on combination therapy expanded poorly relative to monotherapy (24 v. 65-fold, p = 0.014); no significant differences were observed pre-treatment (22 v. 18-fold, p = 0.1578). Post-treatment, the median number of CD8 neoantigens increased in the combination therapy cohort (11 to 15) but in monotherapy were mostly unchanged (6 to 7). Across timepoints, 36% of ATLAS-identified responses overlapped. In silico analysis resulted in 1,895 predicted epitopes among 961 total mutations; among those, 30% were confirmed with ATLAS, although nearly half were Inhibigens, which could not be predicted. Moreover, 50% of confirmed neoantigens were missed by in silico prediction.ConclusionsMonotherapy and combination therapy had differential effects on CD4:CD8 T cell ratios and their non-specific expansion. A greater proportion of neoantigens was identified than previously reported in studies employing in silico predictions prior to empirical verification.2 Overlap between confirmed antigens and in silico prediction was observed, but in silico prediction continued to have a large false negative rate and could not characterize Inhibigens.AcknowledgementsWe would like to acknowledge and thank the patients and their families for participating in this study.ReferencesLam H, McNeil LK, Starobinets H, DeVault VL, Cohen RB, Twardowski P, Johnson ML, Gillison ML, Stein MN, Vaishampayan UN, DeCillis AP, Foti JJ, Vemulapalli V, Tjon E, Ferber K, DeOliveira DB, Broom W, Agnihotri P, Jaffee EM, Wong KK, Drake CG, Carroll PM, Davis TA, Flechtner JB. An empirical antigen selection method identifies neoantigens that either elicit broad antitumor T-cell responses or drive tumor growth. Cancer Discov 2021;11(3):696–713. doi: 10.1158/2159- 8290.CD-20-0377. Epub 2021 January 27. PMID: 33504579. Rosenberg SA. Immersion in the search for effective cancer immunotherapies. Mol Med 27,63(2021). https://doi.org/10.1186/s10020-021-00321-3

scholarly journals Ex Vivo Cytokine and Memory T Cell Responses to the 42-kDa Fragment ofPlasmodium falciparumMerozoite Surface Protein-1 in Vaccinated Volunteers

2008 ◽  
Vol 180 (3) ◽  
pp. 1451-1461 ◽  
Author(s):  
Maria Cecilia Huaman ◽  
Laura B. Martin ◽  
Elissa Malkin ◽  
David L. Narum ◽  
Louis H. Miller ◽  
...  
Keyword(s):  
T Cell ◽  
Ex Vivo ◽  
Surface Protein ◽  
T Cell Responses ◽  
Memory T Cell ◽  
Cell Responses

Long term results from a phase 1 trial of GEN-009, a personalized neoantigen vaccine, combined with PD-1 inhibition in advanced solid tumors.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2613-2613
Author(s):  
Maura L. Gillison ◽  
Mark M. Awad ◽  
Przemyslaw Twardowski ◽  
Ammar Sukari ◽  
Melissa Lynne Johnson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Solid Tumors ◽  
Salvage Therapy ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Long Term Results ◽  
Advanced Solid Tumors ◽  
Cell Responses

2613 Background: GEN-009 is an adjuvanted personalized cancer vaccine containing up to 20 neoantigens selected by ATLAS, an ex vivo bioassay screening autologous T cells for immune responses against both neoantigens as well as Inhibigens. Inhibigen-specific T cells suppress immunity and have been shown to accelerate tumor progression in mice and are avoided in GEN-009. In cohort A, all patients immunized in the adjuvant setting with GEN-009 monotherapy developed immune responses. Nearly all (99%) of selected peptides were immunogenic: ex vivo CD4+ and CD8+ fluorospot responses specific for 51% and 41% of immunized peptides, respectively. Seven of 8 patients continue without progression with a median follow up of 18 months. Methods: GEN-009 is being evaluated in patients (pts) with advanced cancer who received standard-of-care (SOC) PD-1 inhibitor as monotherapy or in combination therapy during vaccine manufacturing. Five vaccine doses were administered over 24 weeks in combination with a PD-1 CPI. Patients who progressed prior to vaccination received alternative salvage therapy followed by GEN-009 in combination. Peripheral T cell responses were measured by fluorospot assays in ex vivo and in vitro stimulation. Results: 15 pts received GEN-009 in combination with a PD-1 inhibitor; 1 patient received GEN-009 monotherapy. Median number of neoantigens per vaccine was 14 (5-18). GEN-009-related adverse events were limited to vaccine injection site reactions and mild myalgias or fatigue. Longitudinal evaluation of ex vivo T cell responses revealed that sequential vaccination with GEN-009 had an overall additive effect on the robustness of IFNγ secretion and responses were persistent for at least 6 months in some patients. Epitope spread was detected in CPI sensitive patients, but not in CPI refractory patients receiving salvage therapy. Three patients who responded to PD-1 inhibition followed by disease stabilization then demonstrated further reduction after GEN-009 vaccination that could represent vaccine effect. Eight of 9 CPI responsive patients are progression-free from 3 to 10 months after first vaccine dose. Four of 7 CPI refractory patients have experienced unexpected prolonged stable disease after vaccination of up to 8 months after vaccination. 2 of 2 patients with available samples lost all evidence of circulating tumor DNA including non-targeted neoantigens. Conclusions: Vaccination with GEN-009 in combination with anti-PD-1 CPI in patients with advanced solid tumors shows little additive toxicity. Preliminary data demonstrate induction of broad neoantigen-specific immune responses and epitope spreading in the presence of PD-1 CPI. Broad immunity against tumor specific targets and encouraging patient outcomes support further study. Clinical trial information: NCT03633110.

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