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 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

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.

Ex-Vivo Characterization of Polyclonal Memory CD8+ T-Cell Responses to PRAME-Specific Peptides in Patients with Acute Leukemia and Chronic Myeloid Leukemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2910-2910
Author(s):  
Katayoun Rezvani ◽  
Agnes S. M. Yong ◽  
Abdul Tawab ◽  
Behnam Jafarpour ◽  
Rhoda Eniafe ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
High Avidity ◽  
Cell Responses ◽  
Ifn Γ

Abstract PRAME (Preferentially expressed antigen of melanoma) is aberrantly expressed in hematological malignancies and may be a useful target for immunotherapy in leukemia. We studied CD8+ T-cell responses to four HLA-A*0201-restricted PRAME-derived epitopes (PRA100, PRA142, PRA300, PRA425) in HLA-A*0201-positive patients with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML) and healthy donors, using PRA300/HLA-A*0201 tetramer staining, intracellular cytokine (IC) assay and ex-vivo and cultured ELISPOT analysis. CD8+ T-cells recognizing PRAME peptides were detected directly ex-vivo in 4/10 ALL, 6/10 AML, 3/10 CML patients and 3/10 donors. The frequency of PRAME-specific CD8+ T-cells was greater in patients with AML, CML and ALL than in healthy controls. All peptides were immunogenic in patients, whilst PRA300 was the only immunogenic peptide in donors. High PRAME expression in patient peripheral blood mononuclear cells was associated with responses to two or more PRAME epitopes (4/7 vs. 0/23 in individuals with low PRAME expression, P = 0.001), suggesting a PRAME-driven T-cell response. In 2 patients studied PRA300/HLA-A*0201+ CD8+T-cells were found to be a mixture of effector and central memory phenotypes. To determine the functional avidity of the PRAME T-cell response, the response of CD8+ T-cells to stimulation with 2 concentrations of peptide was measured by IC-IFN-γ staining. High-avidity CD8+ T-cells were defined as those capable of producing IFN-γ in response to the lower concentration of peptide (0.1μM), while low-avidity CD8+ T-cells were those that only produced IFN-γ in response to the higher concentration of peptide (10 μM). Both high and low-avidity CD8+ T-cell responses could be detected for all peptides tested (median 1.05, 0.90, 0.52, 0.40 high/lowavidity ratios for PRA100, PRA142, PRA300 and PRA425 respectively). In patients with high PRAME expression (>0.001 PRAME/ABL) low-avidity CD8+ T-cell responses to PRAME peptides were more prominent than high-avidity responses, suggesting selective deletion of high-avidity T-cells. In contrast, in some patients with levels <0.001 PRAME/ABL, we could detect the presence of high-avidity CD8+ T-cell responses to PRAME. PRAME-specific CD8+ T-cells were further characterized by IC staining for IL-2, IL-4 and IL-10 production and CD107a mobilization (as a marker of cytotoxicity). Following stimulation with the relevant PRAME peptide, there was no significant production of IL-2, IL-4 or IL-10, suggesting a Tc1 effector response but no significant CD107a mobilization was detected despite significant CD107a mobilization in the same patient in response to CMVpp65495. This finding suggests that patients with leukemia have a selective functional impairment of PRAME-specific CD8+ T-cells, consistent with PRAME-specific T cell exhaustion. However, PRAME-specific T-cells were readily expanded in the presence of cytokines in short-term cultures in-vitro to produce IFN-γ, suggesting that it may be possible to improve the functional capacity of PRAME-specific T-cells for therapeutic purposes. These results provide evidence for spontaneous T-cell reactivity against multiple epitopes of PRAME in ALL, AML and CML and support the usefulness of PRAME as a target for immunotherapy in leukemia. The predominance of low-avidity PRAME-specific CD8+ T-cells suggests that achievement of a state of minimal residual disease may be required prior to peptide vaccination to augment T-cell immune surveillance.

Imiquimod: A TLR-7 agonist as adjuvant for a recombinant protein cancer vaccine

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 8545-8545
Author(s):  
S. Adams ◽  
D. O'Neill ◽  
D. Nonaka ◽  
O. Manches ◽  
L. Chiriboga ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Intracellular Cytokine Staining ◽  
T Cell Responses ◽  
Protein Vaccine ◽  
Imiquimod Cream ◽  
Antigen Uptake ◽  
Cell Responses ◽  
Cell Immunity

8545 Purpose: This clinical trial evaluates the safety and adjuvant activity of imiquimod, a toll-like receptor (TLR)-7 agonist, when given with a NY-ESO-1 protein vaccine. Imiquimod, by locally activating and recruiting dendritic cells (DCs) into the skin, is expected to stimulate antigen uptake by DCs, induce maturation and migration to draining lymph nodes, and to induce antigen-specific T and B cell immunity. Methods: Pilot study; 9 patients with resected stage 2B-3C malignant melanoma. Four 21 day cycles consisted of topical imiquimod cream (250 mg) on days 1–5 and id. injected NY-ESO-1 protein (100 mcg) into the site on day 3. Blood was drawn at several time points for immune monitoring; skin punch biopsies were obtained from control, imiquimod and vaccination sites 48 hours after the last vaccination. Results: The regimen was tolerated well, all patients completed four vaccinations. AEs were mild and transient and included injection site reactions (8/9 patients), fatigue (4/9 patients) and fever (2/9 patients). Significant levels of antigen-specific CD4+ or CD8+ T cell responses were not detected in ex-vivo ELISPOT assays. However, intracellular cytokine staining assays after in vitro pre-stimulation indicated that 6 of 8 subjects developed NY-ESO-1 CD4+ T cell responses. Humoral immunity was manifest by the induction of anti-NY-ESO-1 antibodies in 7/9 patients post-vaccination. Histochemistry of skin sections showed significant dermal mononuclear cell infiltrates in Imiquimod treated skin, whereas none were seen in untreated skin (p<0.01). IHC revealed markedly increased numbers of CD3+ (T-cells), CD68+ (macrophages/monocytes), CD123+ (plasmacytoid DCs) and DC-LAMP+ (mature myeloid DCs) immune cells in Imiquimod treated skin when compared with control skin of the same patients (p<0.05). Conclusion: Imiquimod, a topical immune response modifier, generated clear inflammatory infiltrates in the dermis, with significant increases in antigen-presenting cells and T cells. Imiquimod was well tolerated when used as an adjuvant to an NY-ESO-1 protein vaccine. Systemic immunity of both humoral and cellular types was induced in the majority of patients; however, responses were weak and the vaccine combination needs to be optimized in future studies. No significant financial relationships to disclose.

scholarly journals Safety and exceptional immunogenicity of novel 5T4 viral vectored vaccination regimes in early stage prostate cancer: a phase I clinical trial

2020 ◽  
Author(s):  
Federica Cappuccini ◽  
Richard Bryant ◽  
Emily Pollock ◽  
Lucy Carter ◽  
Clare Verrill ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Early Stage ◽  
Specific Antigen ◽  
T Cell Responses ◽  
Cell Responses ◽  
Cell Immunity

AbstractProstate cancer (PCa) has been under investigation as a target for antigen-specific immunotherapies in metastatic disease settings for a decade. However, neither of the two clinically most developed prostate cancer vaccines, Sipuleucel-T and ProstVac, induce strong T cell immunity. In this first-in-man study, VANCE, we evaluated a novel vaccination platform based on two replication-deficient viruses, chimpanzee adenovirus (ChAd) and MVA (Modified Vaccinia Ankara), targeting the oncofetal self-antigen 5T4 in early stage PCa. Forty patients, either newly diagnosed with early stage prostate cancer and scheduled for radical prostatectomy or patients with stable disease on an active surveillance protocol, were recruited to the study to assess the vaccine safety and T cell immunogenicity. Secondary and exploratory endpoints included immune infiltration into the prostate, prostate specific antigen (PSA) change and assessment of phenotype and functionality of antigen-specific T cells. The vaccine had an excellent safety profile. Vaccination-induced 5T4-specific T cell responses were measured in blood by ex vivo IFN-γ ELISpot and were detected in the majority of patients with a mean level in responders of 198 spot-forming cells (SFC) per million peripheral blood mononuclear cells (PBMCs). Flow cytometry analysis demonstrated the presence of both CD8+ and CD4+ polyfunctional 5T4-specific T cells in the circulation. 5T4-reactive tumour infiltrating lymphocytes (TILs) were isolated from post-treatment prostate tissue. Some of the patients had a transient PSA rise 2-8 weeks following vaccination, possibly indicating an inflammatory response in the target organ. The potent T cell responses elicited support the evaluation of these vectored vaccine in efficacy trials.

scholarly journals Human CLEC9A antibodies deliver NY-ESO-1 antigen to CD141+ dendritic cells to activate naïve and memory NY-ESO-1-specific CD8+ T cells

2020 ◽  
Vol 8 (2) ◽  
pp. e000691 ◽  
Author(s):  
Kelly-Anne Masterman ◽  
Oscar L Haigh ◽  
Kirsteen M Tullett ◽  
Ingrid M Leal-Rojas ◽  
Carina Walpole ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Effector Function ◽  
Immunogenic Tumor ◽  
Cross Presentation ◽  
Cell Responses

BackgroundDendritic cells (DCs) are crucial for the efficacy of cancer vaccines, but current vaccines do not harness the key cDC1 subtype required for effective CD8+ T-cell-mediated tumor immune responses. Vaccine immunogenicity could be enhanced by specific delivery of immunogenic tumor antigens to CD141+ DCs, the human cDC1 equivalent. CD141+ DCs exclusively express the C-type-lectin-like receptor CLEC9A, which is important for the regulation of CD8+ T cell responses. This study developed a new vaccine that harnesses a human anti-CLEC9A antibody to specifically deliver the immunogenic tumor antigen, NY-ESO-1 (New York esophageal squamous cell carcinoma 1), to human CD141+ DCs. The ability of the CLEC9A-NY-ESO-1 antibody to activate NY-ESO-1-specific naïve and memory CD8+ T cells was examined and compared with a vaccine comprised of a human DEC-205-NY-ESO-1 antibody that targets all human DCs.MethodsHuman anti-CLEC9A, anti-DEC-205 and isotype control IgG4 antibodies were genetically fused to NY-ESO-1 polypeptide. Cross-presentation to NY-ESO-1-epitope-specific CD8+ T cells and reactivity of T cell responses in patients with melanoma were assessed by interferon γ (IFNγ) production following incubation of CD141+ DCs and patient peripheral blood mononuclear cells with targeting antibodies. Humanized mice containing human DC subsets and a repertoire of naïve NY-ESO-1-specific CD8+ T cells were used to investigate naïve T cell priming. T cell effector function was measured by expression of IFNγ, MIP-1β, tumor necrosis factor and CD107a and by lysis of target tumor cells.ResultsCLEC9A-NY-ESO-1 antibodies (Abs) were effective at mediating delivery and cross-presentation of multiple NY-ESO-1 epitopes by CD141+ DCs for activation of NY-ESO-1-specific CD8+ T cells. When benchmarked to NY-ESO-1 conjugated to an untargeted control antibody or to anti-human DEC-205, CLEC9A-NY-ESO-1 was superior at ex vivo reactivation of NY-ESO-1-specific T cell responses in patients with melanoma. Moreover, CLEC9A-NY-ESO-1 induced priming of naïve NY-ESO-1-specific CD8+ T cells with polyclonal effector function and potent tumor killing capacity in vitro.ConclusionsThese data advocate human CLEC9A-NY-ESO-1 Ab as an attractive strategy for specific targeting of CD141+ DCs to enhance tumor immunogenicity in NY-ESO-1-expressing malignancies.

GEN-009, a neoantigen vaccine containing ATLAS selected neoantigens, to generate broad sustained immunity against immunogenic tumor mutations and avoid inhibitory peptides.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 3107-3107 ◽  
Author(s):  
Roger B. Cohen ◽  
Przemyslaw Twardowski ◽  
Melissa Lynne Johnson ◽  
Maura L. Gillison ◽  
Mark N. Stein ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Progression ◽  
Ex Vivo ◽  
Phase 1 ◽  
T Cell Responses ◽  
Patient Specific ◽  
Clinical Activity ◽  
Tumor Type ◽  
Inhibitory Peptides ◽  
Cell Responses

3107 Background: Tumor-specific neoantigens provide personalized targets for immunotherapy. Vaccines against epitopes predicted by in silico approaches very rarely induce CD4+ and CD8+ ex vivo T cell responses regardless of formulation. ATLAS selects neoantigens for vaccine inclusion using ex vivo screening of all patient-specific mutations to identify pre-existing CD4+ or CD8+ T cell responses and to exclude Inhibigens, which are inhibitory peptides that suppress immunity and accelerate tumor progression. The Inhibigen burden correlates with patient outcomes in observational studies and rapid tumor progression in mouse models. Methods: GEN-009-101 is a phase 1/2a study testing safety, immunogenicity and clinical activity in immune responsive tumors. After next-generation tumor sequencing and ATLAS testing of autologous leukocytes, up to 20 stimulatory synthetic long peptides adjuvanted with poly-ICLC comprise each personalized vaccine. Eight vaccinated patients have been followed for sustained immunological responses and clinical outcomes. Results: The 40 doses given across patients have induced only mild local discomfort and no DLT. Vaccination has generated immune responses against 99% of administered peptides, with both CD8+ and CD4+ responses in ex vivo fluorospot assays. To date, no patients have developed recurrent disease. Broad immunity develops as early as Day 29 and is sustained for over 12 months. Immune response against individual peptides is correlated with peptide concentration (OR = 1.26, p≤0.0001) but not with other classifiers such as GRAVY index (Grand Average of Hydropathy), tumor type, injection site or sex. The Inhibigen burden prior to treatment again correlates with disease progression. Conclusions: GEN-009 identifies tumor specific immune targets from the individual patient’s tumor mutagens. Initial clinical data show that ATLAS antigen selection may be critical to the induction of broad, rapid and sustained immunity against tumor specific neoantigens. Clinical vaccination with PD-1 blockade is in process. Clinical trial information: NCT03633110 . [Table: see text]

RNA Based Cancer Vaccines - Clinical Trials in Patients with Prostate Cancer and Malignant Melanoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1805-1805
Author(s):  
Gunnar Kvalheim ◽  
Steinar Aamdal ◽  
Gustav Gaudernack
Keyword(s):  
Prostate Cancer ◽  
T Cell ◽  
Malignant Melanoma ◽  
Cancer Patients ◽  
Ex Vivo ◽  
T Cell Responses ◽  
T Cell Response ◽  
Patient Specific ◽  
Cell Responses ◽  
Melanoma Patients

Abstract Anti-tumour vaccines targeting the entire tumour antigen repertoire represent an attractive immunotherapeutic approach. This repertoire is present in the total mRNA isolated from the tumour. The mRNA from each cancer patient may be amplified and thus overcome the problem of limitation of material that has hampered the development of individualized vaccines. We have developed immuno-gene-therapy for malignant melanoma and prostate cancer. Monocyte-derived dendritic dells are transfected with autologous melanoma-mRNA or mRNA from three prostate cancer cell lines (DU-145, LN-CaP and PC-3). The vaccines may generate T cell responses against a broad repertoire of tumor-associated epitopes, and the melanoma approach moreover target patient-specific tumor antigens. Effective protocols were established for mRNA-transfection by square wave electroporation and for generation of clinical grade dendritic cells. A full scale preclinical evaluation demonstrated in vitro T cell responses in 6/6 advanced melanoma patients. The responses were specific to antigens encoded by the transfected tumor-mRNA. Recently, we have conducted two phase I/II trials, in advanced malignant melanoma and androgen-resistant prostate cancer. Successful vaccine preparations were obtained for all 41 patients elected. No serious adverse effects were observed. Specific T cell responses (T cell proliferation and/or IFNγ ELISPOT) were demonstrated in 9/19 evaluable melanoma patients and in 12/19 prostate cancer patients. The response rates were higher for patients receiving intradermal vaccination, compared to intranodal injection. Thirteen prostate cancer patients developed a decrease in log-slope PSA. The PSA-response was significantly related to the T cell response (p=0,002). We conclude that the tumour mRNA based DC-vaccine is feasible and safe, and that T cell responses are elicited in about 50% of patients. In the next generation clinical protocols, patients will undergo Treg depletion by chemotherapy (Temozolomide) prior to DC vaccination. Subsequently, T cells will be expanded ex vivo using the Dynabeads Clin Ex Vivo system before re-infusion into the patients.

HLA-Class I Alleles Impact Susceptibility To EBV+ Classical Hodgkin Lymphoma By Altering EBV Latent Antigen-Specific CD8+ T-Cell Immune Hierarchies

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 630-630
Author(s):  
Maher K Gandhi ◽  
Rebekah M Brennan ◽  
Leesa Wockner ◽  
Pratip K Chattopadhyay ◽  
Mario Roederer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Hla Class I ◽  
Cd8 T Cell ◽  
T Cell Immunity ◽  
Class I ◽  
Cell Responses ◽  
Cell Immunity

Abstract In Epstein-Barr virus (EBV) classical Hodgkin lymphoma (EBV+ cHL), Hodgkin-Reed Sternberg cell antigen presentation is intact, with viral expression restricted to sub-dominant latent-antigens including LMP1/2A. Large epidemiological studies have reported differential HLA-class I (HLA-I) susceptibility to EBV+ cHL. The functional basis for these observations is unknown. HLA-I molecules present viral peptides for recognition by CD8+ T-cells, and it may be that the relative risk of developing EBV+ cHL is due to HLA-I alleles influencing the magnitude of CD8+ T-cell immunity against relevant EBV-specific antigens. However this remains speculative, with immunological evidence lacking. Several non-HLA-I linked genetic susceptibility loci have been identified, and HLA-I associations may simply represent markers for genes of diverse functions that are in linkage disequilibrium to the HLA-I region. We undertook an Australasian Leukaemia and Lymphoma Group study to address this fundamental question, utilizing 4 distinct but complimentary experimental approaches. 1. 9 EBV+ cHL and 11 EBV-ve cHL pre-therapy PBMC samples were tested for ex-vivo IFNγ, TNFα and CD107a CD8+ T-cell immunity, using overlapping LMP1 and LMP2A peptide pools. The non-HRS expressed EBV-lytic protein BZLF1 was a control. Highly stringent FACS gating was used to maximize specificity. Results were interrogated using Profile and SPICE analysis. Interestingly IFNγ, TNFα and CD107 CD8+ T-cell responses in HLA-A*02 EBV+ cHL (but not EBV-ve cHL) patients were greater than non-HLA-A*02 (LMP1 p=0.002; LMP2A p=0.03; combined LMP1/LMP2A p=0.005), whereas BZLF1 was equivalent, indicating that HLA-I provides differential CD8+ T-cell immunity against relevant EBV-latent antigens in EBV+ cHL but not EBV-ve cHL. 2. However, up to 4 different HLA-A/B molecules can potentially present relevant EBV-derived epitopes in each individual, adding a confounding layer of complexity to single allele-based effects. To overcome this and enhance sensitivity, we used the mutant HLA-I 721.221 cell-line (pulsed with LMP2A), transfected with either HLA-A*01, HLA-A*02, HLA-A*03 or HLA-B*08 alleles, as antigen presenting cells to in-vitro expand LMP2A-specific CD8+ T-cells from HLA-A*02 heterozygotes. This found ∼90% of the HLA-I LMP2A response was restricted through HLA-A*02. 3. In contrast to EBV+ cHL, in EBV-post-transplant lymphoproliferative disorders (EBV+ PTLD) the immunogenic EBNA3A/3B/3C latent-antigens are expressed. We compared HLA-I associations in 110 cHL (35% EBV+ cHL) to 153 PTLD (63% EBV+ PTLD) patients. Using Bonferoni corrected statistics, we confirmed that HLA-A*02 and HLA-A*01 homozygotes had lower and higher susceptibility to EBV+ cHL respectively, and that HLA-B*37 was positively associated. Notably, no HLA-I associations with EBV+ PTLD were found. 4. To investigate the impact of HLA-I on the hierarchy of CD8+ T-cell immunity to sub-dominant (LMP1/2A) and immune-dominant (EBNA3A/3B/3C) EBV-latent proteins, we analysed the diversity of HLA-class I restricted T-cells in 30 healthy EBV+ participants. To supplement 30 ‘defined' (i.e. validated) HLA-I EBV-latent antigen epitopes and expand HLA-I coverage, we identified 31 ‘SYFPEITHI' bioinformatically ‘predicted' peptide epitopes for HLA-A*01, HLA-A*03 or HLA-B*37 restricted EBV-latent antigens. All SYFPEITHI scores were ≥21, and thermal stability circular dichroism analysis (HLA-A*01) or MHC stabilization assays on T2 cells (HLA-A*03) confirmed peptide binding to HLA-I. Ex-vivo CD107 CD8+ T-cell assays for the 61 peptides, found that sub-dominant LMP1/2A-specific peptide responses were largely confined to HLA-A*02 (Fig 1A), whilst immuno-dominant CD8+ T-cell responses were stimulated by peptides presented by numerous HLA-I alleles (Fig 1B). These data combined illustrate that differential HLA-I-associated susceptibility to EBV+ cHL reflects altered EBV latent antigen-specific CD8+ T-cell immune hierarchies. For lymphomas expressing a restricted set of poorly immunogenic proteins, even modest CD8+ T-cell responses against relevant tumor-associated proteins confer protection, with broad implications for EBV-vaccine design. Studies are required to determine if similar mechanisms are applicable to non-lymphoid EBV+ malignancies with restricted latency such as undifferentiated nasopharngeal carcinoma. Disclosures: No relevant conflicts of interest to declare.

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