Izar, Benjamin

TPS4208 Background: Metastatic pancreatic ductal adenocarcinoma (mPDAC) carries a 5-year relative survival of 3%. Immune checkpoint inhibitors have thus far failed to improve outcomes due to an immunosuppressive tumor microenvironment (TME). Signaling through the C-X-C motif chemokine receptor 4 (CXCR4)/C-X-C motif chemokine ligand 12 (CXCL12) axis results in exclusion of anti-tumor immune cells in mouse PDAC models. Longitudinal survival studies testing combinations of CXCR4i, aPD-1, and gemcitabine in the KPC mouse model of PDAC demonstrated a survival benefit with the combination of all three agents. Results from a multicenter, investigator-initiated, single arm pilot study evaluating the preliminary safety and efficacy ofMotixafortide (CXCR4i), Cemiplimab (aPD1), Gemcitabine, and Nab-paclitaxel (MCGN) in 11 patients with treatment-naïve mPDAC were recently presented. Seven patients (64%) achieved a partial response, including 6 confirmed partial responses, and 10 patients (91%) had disease control, compared to historic partial response and disease control rates of 23% and 48%, respectively, with gemcitabine and nab-paclitaxel (GN). Preliminary median progression-free survival (PFS) was 9.6 months compared to historic median PFS of 5.5 months with GN. Analysis of paired pre- and on-treatment biopsy samples from demonstrated an increase in CD8+ T-cell density in tumors from all 11 patients treated with MCGN (p=0.007). Based on these promising results, the protocol was amended from a single arm expansion totaling 40 patients to a randomized phase 2 study. Methods: This is an open-label, multicenter, investigator-initiated phase 2 clinical trial. Patients are randomized 2:1 to receive MCGN or GNalone (N=108). The primary endpoint is progression free survival. The study has 80% power to detect an improvement in PFS from 6 to 9.2 months (HR 0.65) with a one-sided alpha of 0.20. One interim analysis for futility is planned when 50% of the PFS events are observed. Secondary objectives include response rate, disease control rate, duration of clinical benefit and overall survival. Patients will undergo optional paired biopsies which will be analyzed in conjunction with samples collected from the phase I pilot study. Exploratory studies include interrogation of the TME using quantitative multiplex immunofluorescence and single-cell RNA sequencing. The randomized phase 2 trial is open to enrollment and one patient has been randomized as of 1/29/2024. Clinical trial information: NCT04543071 .

Since the first approval for immune checkpoint inhibitors (ICIs) for the treatment of cutaneous melanoma more than a decade ago, immunotherapy has completely transformed the treatment landscape of this chemotherapy-resistant disease. Combination regimens including ICIs directed against programmed cell death protein 1 (PD-1) with anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) agents or, more recently, anti-lymphocyte-activation gene 3 (LAG-3) agents, have gained regulatory approvals for the treatment of metastatic cutaneous melanoma, with long-term follow-up data suggesting the possibility of cure for some patients with advanced disease. In the resectable setting, adjuvant ICIs prolong recurrence-free survival and several are FDA-approved. Although not yet approved, neoadjuvant ICIs have also shown to improve event-free survival and remains an ongoing area of investigation. Other immunotherapy strategies, such as oncolytic virotherapy for injectable cutaneous melanoma, bispecific T-cell engager therapy for HLA-A*02:01 genotype-positive uveal melanoma, and lifileucel, an autologous tumor-infiltrating lymphocyte therapy, for unresectable or metastatic melanoma are also available to patients. Despite the remarkable efficacy of these regimens for many patients with cutaneous melanoma, traditional immunotherapy biomarkers (ie, programmed death-ligand 1 expression, tumor mutational burden, T-cell infiltrate and/or microsatellite stability) have failed to reliably predict response. Furthermore, ICIs are associated with unique toxicity profiles, particularly for the highly active combination of anti-PD-1 plus anti-CTLA-4 agents. The Society for Immunotherapy of Cancer (SITC) convened a panel of experts to develop this clinical practice guideline on immunotherapy for the treatment of melanoma, including rare subtypes of the disease (eg, uveal, mucosal), with the goal of improving patient care by providing guidance to the oncology community. Drawing from published data and clinical experience, the Expert Panel developed evidence- and consensus-based recommendations for healthcare professionals using immunotherapy to treat melanoma, with topics including therapy selection in the advanced and perioperative settings, intratumoral immunotherapy, when to use immunotherapy for patients with BRAF V600-mutated disease, management of patients with brain metastases, evaluation of treatment response, special patient populations, patient education, quality of life, and survivorship, among others.

Current methods for biomarker discovery and target identification in immuno-oncology rely on static snapshots of tumor immunity. To thoroughly characterize the temporal nature of antitumor immune responses, we developed a 34-parameter spectral flow cytometry panel and performed high-throughput analyses in critical contexts. We leveraged two distinct preclinical models that recapitulate cancer immunoediting (NPK-C1) and immune checkpoint blockade (ICB) response (MC38), respectively, and profiled multiple relevant tissues at and around key inflection points of immune surveillance and escape and/or ICB response. Machine learning-driven data analysis revealed a pattern of KLRG1 expression that uniquely identified intratumoral effector CD4 T cell populations that constitutively associate with tumor burden across tumor models, and are lost in tumors undergoing regression in response to ICB. Similarly, a Helios-KLRG1+ subset of tumor-infiltrating regulatory T cells was associated with tumor progression from immune equilibrium to escape and was also lost in tumors responding to ICB. Validation studies confirmed KLRG1 signatures in human tumor-infiltrating CD4 T cells associate with disease progression in renal cancer. These findings nominate KLRG1+ CD4 T cell populations as subsets for further investigation in cancer immunity and demonstrate the utility of longitudinal spectral flow profiling as an engine of dynamic biomarker discovery.