Greenwich LifeSciences (GLSI) Reports Positive Phase 3 Data for Breast Cancer Vaccine GLSI-100

Shares of Greenwich LifeSciences Inc. (NASDAQ: GLSI) surged on June 1, 2026, after the company announced its experimental breast cancer vaccine GLSI-100 met the primary endpoint in the pivotal Phase 3 FLAMINGO-01 trial. The double-­blind, placebo‐controlled study showed a statistically significant reduction in recurrence of HER2/neu-positive breast cancer in patients who received GLSI-100 after standard treatment. Company executives presented the full dataset at a major medical conference, though detailed figures were not immediately released in the press statement. CEO Snehal Patel said the results position GLSI-100 as a potential first-in-class therapy to prevent disease relapse. Greenwich now plans to submit a Biologics License Application to the U.S. Food and Drug Administration within six months. The company also aims to file for European Medicines Agency approval in 2027. Analysts see peak sales potential exceeding $3 billion if approved, but emphasize regulatory hurdles remain.