Phase 1 ITI-5000 saRNA vaccine targets HERV-K/CT83 tumor antigens (LAMP-1 enhanced)

This first-in-human, Phase 1, multicenter, open-label study (VITAL-TNBC) tests ITI-5000, a lipid-nanoparticle (LNP)–delivered self-amplifying RNA (saRNA) therapeutic vaccine from Immunomic Therapeutics in people with stage II–III triple-negative breast cancer who have completed standard curative-intent therapy. ITI-5000 encodes two TNBC-associated antigens (HERV-K and CT83/KK-LC-1) fused to LAMP-1 to boost antigen processing and T-cell priming, aiming to generate durable anti-tumor immune memory in the post-treatment “minimal residual disease” setting. Part A dose-escalates ITI-5000 monotherapy (1 µg vs 10 µg IM every 28 days for 3 doses) to define a recommended dose; Part B adds Merck’s pembrolizumab (Keytruda), a PD-1–blocking monoclonal antibody, dosed per label (200 mg every 3 weeks or 400 mg every 6 weeks) alongside vaccine injections every 21 days for 3 doses. The scientific angle is a low-dose saRNA cancer vaccine strategy paired with checkpoint blockade, designed to convert vaccine-primed T cells into effective surveillance. Today’s care for stage II–III TNBC is neoadjuvant chemotherapy plus pembrolizumab followed by surgery, then adjuvant pembrolizumab (and capecitabine or olaparib for selected residual disease/genetic subgroups), with limited options specifically aimed at vaccine-like immune memory once curative therapy is complete.