A Randomized, Placebo-controlled Phase 3 Study of HER2Neu Peptide GLSI-100 Immunotherapy in HER2Neu Positive Subjects With Residual or High-Risk Disease After Trastuzumab Therapy

What this Trial Is About

Researchers are evaluating the efficacy and safety of GLSI-100 immunotherapy in people with HER2neu positive breast cancer who are at high risk for the disease returning. The study focuses on participants who are HLA-A02 positive and have completed both neoadjuvant and postoperative adjuvant trastuzumab-based therapy. This Phase 3 trial includes a third open-label group for non-HLA-A02 positive subjects. Participants receive either GLSI-100 immunotherapy or a placebo through intradermal injections. The treatment schedule includes a Primary Immunization Series of 6 injections over the first 6 months, followed by 5 booster injections spaced 6 months apart, totaling 11 injections over 3 years. The open-label arm also receives GLSI-100 following the same injection schedule. During the study, participants will be monitored for invasive breast cancer-free survival over a median follow-up of 4 years, with interim analyses planned. Secondary outcomes include disease-free survival, overall survival, and quality of life assessments at baseline and 36 months. Safety and treatment effects will be evaluated throughout the trial, which is expected to continue until December 2026.

Phase 3 Study to Evaluate the Efficacy and Safety of HER2/Neu Peptide GLSI-100 (GP2 + GM-CSF) in HER2/Neu Positive Subjects