Greenwich LifeSciences, Inc. (NASDAQ: GLSI) provided an update on its Phase 3 FLAMINGO-01 trial evaluating GLSI-100, an immunotherapy designed to prevent breast cancer recurrence. The company announced that the study’s Data Safety Monitoring Board (DSMB) recommended the trial continue without modification following its May 2026 review. This independent oversight provides confidence in the trial's safety profile and supports ongoing patient enrollment.
Regulatory authorities in the United States and Europe have supported planned protocol changes that include expanding enrollment to as many as 2,000 patients. The changes also include increasing enrollment rates by including all HLA types and maintaining enrollment through interim analyses to strengthen the study design and increase the probability of success. These modifications aim to enhance the robustness of the trial data and potentially accelerate the path to regulatory approval.
Greenwich LifeSciences reported that more than 1,500 patients have been screened across approximately 170 to 180 clinical sites in 11 countries. The company plans to expand into additional European markets as well as the United Kingdom and Canada, broadening the geographic reach of the trial. This expansion could improve patient diversity and representativeness, which are critical for generalizing trial results to broader populations.
The company also reported preliminary data from the fully enrolled open-label non-HLA-A*02 arm, which continues to show a 70% to 80% reduction in breast cancer recurrence following the primary immunization series. However, the company emphasized that these findings remain preliminary and are not predictive of the final Phase 3 results. Investors and clinicians should interpret these data with caution until the full trial results are available and peer-reviewed.
GLSI-100 targets GP2, a 9 amino acid transmembrane peptide of the HER2 protein, which is expressed in 75% of breast cancers at low, intermediate, and high levels. The immunotherapy aims to prevent breast cancer recurrences in patients who have previously undergone surgery. If successful, GLSI-100 could offer a new treatment option for a significant portion of breast cancer patients, potentially reducing the risk of recurrence and improving long-term outcomes.
The implications of this trial are substantial for the breast cancer community. Breast cancer remains one of the most common cancers worldwide, and recurrence after initial treatment is a major concern. An effective immunotherapy that reduces recurrence risk could change standard of care and provide hope for patients with HER2-expressing tumors. For the biotechnology industry, positive results could validate the approach of targeting HER2 with peptide-based immunotherapies and open doors for similar treatments in other cancers.
For more information about Greenwich LifeSciences and the FLAMINGO-01 trial, visit the company’s website at www.greenwichlifesciences.com. The full press release is available at https://ibn.fm/elLnN.
