A phase I study of the safety and immunogenicity of a multipeptide personalized genomic vaccine in the adjuvant treatment of solid cancers.

Abstract

TPS3114 Background: Mutation-derived tumor antigens (MTAs) arise as a direct result of somatic variations, including nucleotide substitutions, insertions, and deletions that occur during carcinogenesis. These somatic variations can be characterized via genetic sequencing and used to identify MTAs. We propose a platform for a fully-personalized MTA-based vaccine in the adjuvant treatment of solid tumors. Methods: This clinical trial is a single-arm, open label, proof-of-concept phase I study designed to test the safety and immunogenicity of the Personalized Genomic Vaccine 001 (PGV001). The single-center study will enroll 20 eligible subjects with histological diagnosis of the following tumor types: (a) head and neck squamous cell cancer, (b) non-small cell lung cancer, (c) ductal or lobular breast cancer, (d) serous carcinoma of the ovary, uterine adnexa, (e) urothelial carcinoma of renal pelvis or bladder, (f) cutaneous squamous cell cancer. Subjects must have no measurable disease at time of first vaccine administration, and 5-year disease recurrence risk of > 30%. Patients will receive 10 doses of PGV001 as well as 10 doses of poly-ICLC (toll-like receptor-3 agonist, vaccine adjuvant), administered 1 day after PGV001 vaccination. Toxicity (endpoint 1) will be defined by Common Terminology Criteria for Adverse Events v5.0. Blood samples will be collected at various time points for immune response monitoring of MTA-specific humoral and cellular immune responses. For each patient, immunogenicity (endpoint 2) will be defined as an epitope-specific T cell response, detectable in peripheral blood samples after PGV001 vaccination. The change in the frequency of vaccine-induced epitope-specific T lymphocyte populations post-vaccination relative to baseline will be determined using mixed effects linear regression modeling. Conclusions: Our clinical trial will test for the first time the safety and immunogenicity of PGV001 in patients with multiple solid cancers. The information learned from this clinical trial will instruct the next generation of MTA-based vaccines, future development of immunotherapeutic approaches and rational combinations. Clinical trial information: NCT02721043.