Randomized open-label controlled study of cancer vaccine OSE2101 versus chemotherapy in HLA-A2-positive patients with advanced non-small-cell lung cancer with resistance to immunotherapy: ATALANTE-1.

BACKGROUND: Patients with advanced non-small-cell lung cancer (NSCLC) treated with immune checkpoint blockers (ICBs) ultimately progress either rapidly (primary resistance) or after durable benefit (secondary resistance). The cancer vaccine OSE2101 may invigorate antitumor-specific immune responses after ICB failure. The objective of ATALANTE-1 was to evaluate its efficacy and safety in these patients. PATIENTS AND METHODS: ATALANTE-1 was a two-step open-label study to evaluate the efficacy and safety of OSE2101 compared to standard-of-care (SoC) chemotherapy (CT). Patients with human leukocyte antigen (HLA)-A2-positive advanced NSCLC without actionable alterations, failing sequential or concurrent CT and ICB were randomized (2 : 1) to OSE2101 or SoC (docetaxel or pemetrexed). Primary endpoint was overall survival (OS). Interim OS futility analysis was planned as per Fleming design. In April 2020 at the time of interim analysis, a decision was taken to prematurely stop the accrual due to coronavirus disease 2019 (COVID-19). Final analysis was carried out in all patients and in the subgroup of patients with ICB secondary resistance defined as failure after ICB monotherapy second line ≥12 weeks. RESULTS: Two hundred and nineteen patients were randomized (139 OSE2101, 80 SoC); 118 had secondary resistance to sequential ICB. Overall, median OS non-significantly favored OSE2101 over SoC {hazard ratio (HR) [95% confidence interval (CI)] 0.86 [0.62-1.19], P = 0.36}. In the secondary resistance subgroup, OSE2101 significantly improved median OS versus SoC [11.1 versus 7.5 months; HR (95% CI) 0.59 (0.38-0.91), P = 0.017], and significantly improved post-progression survival (HR 0.46, P = 0.004), time to Eastern Cooperative Oncology Group (ECOG) performance status deterioration (HR 0.43, P = 0.006) and Quality of Life Questionnaire Core 30 (QLQ-C30) global health status compared to SoC (P = 0.045). Six-month disease control rates and progression-free survival were similar between groups. Grade ≥3 adverse effects occurred in 11.4% of patients with OSE2101 and 35.1% in SoC (P = 0.002). CONCLUSIONS: In HLA-A2-positive patients with advanced NSCLC and secondary resistance to immunotherapy, OSE2101 increased survival with better safety compared to CT. Further evaluation in this population is warranted.

Phenotypic CD8 T cell profiling in chronic hepatitis B to predict HBV-specific CD8 T cell susceptibility to functional restoration in vitro.

OBJECTIVE: Exhausted hepatitis B virus (HBV)-specific CD8 T cells in chronic HBV infection are broadly heterogeneous. Characterisation of their functional impairment may allow to distinguish patients with different capacity to control infection and reconstitute antiviral function. DESIGN: HBV dextramer+CD8 T cells were analysed ex vivo for coexpression of checkpoint/differentiation markers, transcription factors and cytokines in 35 patients with HLA-A2+chronic hepatitis B (CHB) and in 29 control HBsAg negative CHB patients who seroconverted after NUC treatment or spontaneously. Cytokine production was also evaluated in HBV peptide-stimulated T cell cultures, in the presence or absence of antioxidant, polyphenolic, PD-1/PD-L1 inhibitor and TLR-8 agonist compounds and the effect on HBV-specific responses was further validated on additional 24 HLA-A2 negative CHB patients. RESULTS: Severely exhausted HBV-specific CD8 T cell subsets with high expression of inhibitory receptors, such as PD-1, TOX and CD39, were detected only in a subgroup of chronic viraemic patients. Conversely, a large predominance of functionally more efficient HBV-specific CD8 T cell subsets with lower expression of coinhibitory molecules and better response to in vitro immune modulation, typically detected after resolution of infection, was also observed in a proportion of chronic viraemic HBV patients. Importantly, the same subset of patients who responded more efficiently to in vitro immune modulation identified by HBV-specific CD8 T cell analysis were also identified by staining total CD8 T cells with PD-1, TOX, CD127 and Bcl-2. CONCLUSIONS: The possibility to distinguish patient cohorts with different capacity to respond to immune modulatory compounds in vitro by a simple analysis of the phenotypic CD8 T cell exhaustion profile deserves evaluation of its clinical applicability.

Targeting Merkel Cell Carcinoma by Engineered T Cells Specific to T-Antigens of Merkel Cell Polyomavirus.

Purpose: The causative agent of most cases of Merkel cell carcinoma (MCC) has been identified as the Merkel cell polyomavirus (MCV). MCV-encoded T antigens (Tag) are essential not only for virus-mediated tumorigenesis but also for maintaining MCC cell lines in vitro MCV Tags are thus an appealing target for viral oncoprotein-directed T-cell therapy for MCC. With this study, we aimed to isolate and characterize Tag-specific T-cell receptors (TCR) for potential use in gene therapy clinical trials.Experimental Design: T-cell responses against MCV Tag epitopes were investigated by immunizing transgenic mice that express a diverse human TCR repertoire restricted to HLA-A2. Human lymphocytes genetically engineered to express Tag-specific TCRs were tested for specific reactivity against MCC cell lines. The therapeutic potential of Tag-specific TCR gene therapy was tested in a syngeneic cancer model.Results: We identified naturally processed epitopes of MCV Tags and isolated Tag-specific TCRs. T cells expressing these TCRs were activated by HLA-A2-positive cells loaded with cognate peptide or cells that stably expressed MCV Tags. We showed cytotoxic potential of T cells engineered to express these TCRs in vitro and demonstrated regression of established tumors in a mouse model upon TCR gene therapy.Conclusions: Our findings demonstrate that MCC cells can be targeted by MCV Tag-specific TCRs. Although recent findings suggest that approximately half of MCC patients benefit from PD-1 pathway blockade, additional patients may benefit if their endogenous T-cell response can be augmented by infusion of transgenic MCV-specific T cells such as those described here. Clin Cancer Res; 24(15); 3644-55. ©2018 AACR.

Prediction and preliminary screening of HLA-A*0201-restricted epitope peptides of human GPC3.

In response to the limited therapeutic option for hepatocellular carcinoma (HCC), immunotherapy as a promising approach points out a new direction to the cure of tumours through specific recognition and elimination of tumour cells by the immunity-enhanced autologous immunocytes of patients. Few effective tumour antigens, however, are alternative in addition to alpha fetoprotein or tumour cell lysates. Recent studies have demonstrated that glypican-3 (GPC3) is not only a promising diagnostic marker, but also ideal therapeutic target to HCC. In this study, potential HLA-A*0201 GPC3 peptides were screened with three epitope prediction software, the binding affinity of 13 predicted epitopes with high scores was determined by T2 cells binding assay and four optimal epitopes were identified. This is the first study in which the optimal HLA-A*0201 GPC3 epitopes were screened from a large number of candidates predicted by three software. The optimized HLA-A*0201 GPC3 peptides will provide new epitope candidates for HCC immunotherapy.

Phase I/II study of treatment with dendritic cell vaccines in patients with disseminated melanoma.

Previous studies have suggested that immunotherapy with dendritic cell (DC) vaccines may be effective in treatment of patients with AJCC stage IV melanoma. We examined this treatment in phase I/II studies in 33 patients with good performance status and low volume disease. Nineteen patients received DCs plus autologous lysates and 14 patients DCs plus peptides from the melanoma antigens MAGE-3.A2, tyrosinase, gp100, and MART-1. Keyhole limpet hemocyanin (KLH) was used as a helper protein and influenza peptide was given as a positive control. DCs were produced from adherent cells in blood lymphocytes (monocytic DCs), grown in IL-4 and GM-CSF without a maturation step. The DCs were injected into inguinal lymph nodes at weekly intervals (x4), 2 weeks (x1), and 4-weekly intervals (x2). There were 3 responses (3 partial responses) and 1 mixed response in the 19 patients treated with DCs plus autologous lysates. No responses were seen in the group treated with DCs plus peptides. Stable disease (defined as no progression over a period of 3 months) was seen in 4 patients in group 1 and 5 patients in group 2. Treatment was not associated with significant side effects. We examined whether DTH skin tests or assays of IFN-gamma cytokine production may be useful predictors of clinical responses. Twenty-two of 30 patients had DTH responses to KLH and 12 of 13 patients had DTH responses to the influenza peptide. Five of 15 DTH responses were seen against autologous lysates. This was strongly correlated with clinical responses. Approximately half the patients had responses to MART-1 peptide and a third to the other melanoma peptides. Similarly, cytokine production assays showed responses to influenza in 7 of 13 patients, and approximately one third of patients had responses to the other peptides. No IFN-gamma responses were seen in 5 patients against their autologous lysates. There was no correlation between assays of IFN-gamma production and clinical responses. The present studies suggest that autologous lysates may be more effective than the melanoma peptides used in the study as the source of antigen for DC vaccines. DTH responses to autologous lysates appear useful predictors of clinical responses, but further work is needed to identify other measures associated with clinical responses.

Infusion of dendritic cells pulsed with HLA-A2-specific prostate-specific membrane antigen peptides: a phase II prostate cancer vaccine trial involving patients with hormone-refractory metastatic disease.

BACKGROUND: A phase II trial was conducted to assess the efficacy of infusions of dendritic cells (DC) and two HLA-A2-specific PSMA peptides (PSM-P1 and -P2). This report describes thirty three subjects with hormone-refractory metastatic prostate cancer without prior vaccine therapy history who were evaluated and reported as a group. METHODS: All subjects received six infusions of DC pulsed with PSM-P1 and -P2 at six week intervals. Clinical monitoring was conducted pre-, during, and post- phase II study. Data collected include: complete blood count, bone and total alkaline phosphatase, prostate markers, physical examination, performance status, bone scan, ProstaScint scan, chest x-ray, as well as assays to monitor cellular immune responses. RESULTS: Six partial and two complete responders were identified in the phase II study based on NPCP criteria, plus 50% reduction of prostate-specific antigen (PSA), or resolution in previously measurable lesions on ProstaScint scan. CONCLUSIONS: Over 30% of study participants in this group showed a positive response at the conclusion of the trial. This study suggested that DC-based cancer vaccines may provide an alternative therapy for prostate cancer patients whose disease no longer responds to hormone therapy.