Greenwich LifeSciences Gains 32% on FDA Fast Track Designation for Lead Asset GLSI-100 in Treating Subset of Breast Cancer Patients.

Greenwich LifeSciences (NASDAQ:GLSI) stock surged 32% in the premarket after the FDA granted Fast Track designation for its lead asset GLSI-100 to treat a subset of breast cancer patients. The Fast Track designation allows for faster review and approval of the drug.

Greenwich LifeSciences, Inc. (NASDAQ: GLSI) saw its stock surge by 32% in the premarket following the U.S. Food and Drug Administration (FDA) granting Fast Track designation for its lead asset, GLSI-100. The designation is aimed at accelerating the review and approval process for GLSI-100, an immunotherapy intended to prevent breast cancer recurrences in a specific patient population.

The Fast Track designation, granted on September 10, 2025, is for GLSI-100 in the HLA-A*02 patient population. The FDA recognizes the potential of GLSI-100 to improve invasive breast cancer-free survival in patients with HER2-positive breast cancer who have completed standard-of-care HER2/neu targeted therapy. This designation allows for more frequent communication between the FDA and Greenwich LifeSciences, potentially leading to earlier drug approval and access for patients Greenwich LifeSciences' GLSI-100 Granted US FDA Fast ...^[1].

The Fast Track process is designed to expedite the development and review of drugs that treat serious conditions and fill unmet medical needs. By receiving this designation, Greenwich LifeSciences can utilize a rolling review process, where completed sections of the Biologic License Application (BLA) can be submitted for review before the entire application is completed .

The Phase III clinical trial, FLAMINGO-01 (NCT05232916), is evaluating the safety and efficacy of GLSI-100 in HER2-positive breast cancer patients with residual disease or high-risk pathologic complete response. The trial is currently enrolling patients at various sites globally, with a specific focus on the HLA-A*02 patient population .

Greenwich LifeSciences has previously demonstrated promising results in Phase IIb clinical trials, showing an 80% or greater reduction in metastatic breast cancer recurrence rate over five years of follow-up in patients treated with GLSI-100 compared to those treated with placebo .

The stock surge reflects investor optimism about the potential of GLSI-100 to address an unmet medical need and the accelerated timeline for regulatory review and approval. As the trial progresses and more data becomes available, investors will closely monitor the development and outcomes of FLAMINGO-01 to gauge the potential impact on the company's future prospects.