Abstract CT256: Modi-1, anti-citrullinated neoepitope vaccine alone and combined with checkpoint inhibitors in patients with head and neck, breast, renal and ovarian carcinoma: protocol for the ModiFY phase I/II basket clinical Ttial

Abstract Stressful conditions in the tumor microenvironment induce autophagy in cancer cells as a mechanism to promote their survival. High levels of calcium within autophagosomes activates peptidylarginine deaminase enzymes which convert arginine residues within polypeptides to citrulline and alters proteolytic cleavage. In the presence of inflammation, the MHC-II pathway presents these new citrullinated peptides to CD4 T cells. Modi-1 vaccine comprising three citrullinated, adjuvanted peptides induces and expands a population of activated CD4 T cells. On reaching the tumor site the CD4 T cells release proinflammatory cytokines including, INFγ, which upregulates MHC class II and the same, but endogenous, modified peptides are presented on the tumor cell surface. This likely causes a positive feed-forward loop with killing of tumor cells. The objective of this study is to evaluate the safety, tolerability, cellular immune and tumor response to 2 citrullinated vimentin and one citrullinated enolase peptide each conjugated to the toll-like receptor 1/2 adjuvant Amplivant® ModiFY is an open-label, prospective, multicohort, multicenter, phase I/II basket trial. Eligible patients have unresectable disease in one of the following tumor types: Squamous Cell Carcinoma of the Head and Neck (SCCHN), Triple Negative Breast Cancer, Renal Cell Carcinoma and High Grade Serous Ovarian Carcinoma. Depending on the status of the disease and eligibility for standard of care (SOC) checkpoint inhibitor (CPI) monotherapy, patients will be treated either with Modi-1 alone or Modi-1 +SOC CPI. A randomized neoadjuvant sub-study in patients with SCCHN scheduled to have tumor resection surgery is included in the protocol. These patients are randomized 1:1 to receive either Modi-1 alone or Modi-1+ pembrolizumab. The primary endpoints are the adverse event rate as measured by CTCAE v5.0 in the initial dose escalation cohorts and the strength of the cellular immune response IFNγ enzyme-linked immune absorbent spot (ELISpot) assay in the dose expansion cohorts. Secondary endpoints (RECIST 1.1 and iRECIST), are objective response rate duration of response, progression-free survival, and overall survival. In the SCCHN neoadjuvant cohort, tumor infiltrating lymphocytes in resected tumor tissue will be profiled using scRNAseq and immunohistochemistry. The study is an adaptive trial, comprising 3+3 dose escalation cohorts followed by a Simon 2-stage design in the dose expansion cohorts. The Modi-1 only dose expansion cohort will recruit 16 patients of each of the target tumor types, whilst the Modi-1+CPI will recruit a total of 21 patients. A total of 21/138 patients have been treated to date. ClinicalTrials.gov NCT05329532 Citation Format: Lindy G. Durrant, Fayaz Masters, Samantha Paston, Robert Miller, David J. Pinato, Rebecca Herbertson, Anne Armstrong, Stefan Symeonides, Christian Ottensmeier. Modi-1, anti-citrullinated neoepitope vaccine alone and combined with checkpoint inhibitors in patients with head and neck, breast, renal and ovarian carcinoma: protocol for the ModiFY phase I/II basket clinical Ttial [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 CT256.