Mayo's randomized Phase 2 trial across 11 sites tested low-dose (825 μg) against high-dose (2.5 mg) TPIV200, a multi-epitope folate-receptor-alpha peptide vaccine adjuvanted with GM-CSF, with or without cyclophosphamide pretreatment in early-stage triple-negative breast cancer. The low dose matched the full dose on immunogenicity, cyclophosphamide pretreatment had no impact, and vaccination induced persistent polyepitope immunity. Kathryn Ruddy, Keith Knutson, and Saranya Chumsri presented the data June 1.
Mayo Clinic researchers led by Dr. Kathryn Ruddy will present a randomized Phase 2 trial of the folate receptor alpha (FRα) peptide vaccine TPIV200 in early-stage triple-negative breast cancer at ASCO 2026 (Abstract 536, June 1, 1:30-4:30 PM CDT). The trial dosed 80 patients with vaccine; 58 were evaluable for immunogenicity. The TPIV200 multi-epitope FRα peptide vaccine was found safe and immunogenic using a single low-dose injection without cyclophosphamide priming. FRα is overexpressed on the cell surface in breast, ovarian, and lung cancers, making it a shared-antigen vaccine target distinct from personalized neoantigen approaches. The data supports combining TPIV200 with an immune checkpoint inhibitor to extend recurrence-free or progression-free survival in TNBC — the breast cancer subtype with the highest mortality risk and fewest targeted-therapy options. The vaccine adds to the peptide cancer vaccine cohort (BioVaxys MVP-S, Dana-Farber NeoVax, Greenwich GP2) at ASCO 2026.