Greenwich LifeSciences Announces European Approval for Combining Both HLA Populations in FLAMINGO-01
Rhea-AI Summary
Greenwich LifeSciences (Nasdaq: GLSI) reported that the European Medicines Agency has approved combining both HLA-A*02 and non-HLA-A*02 patients in the randomized arms of its Phase III FLAMINGO-01 trial of GLSI-100 to prevent breast cancer recurrences.
All 170-180 clinical sites in the US and Europe now operate under a unified protocol and may continue enrollment to the first interim analysis, with data still analyzable by individual HLA types. According to Greenwich LifeSciences, US protocol changes allowing combined enrollment more than doubled pivotal-arm enrollment rates and made non-HLA-A*02 patients, about 55% of the population, eligible after long waits, creating a pathway to seek approval in both HLA groups and to use increased statistical power from a combined analysis.
Positive
- EMA approval to combine HLA-A*02 and non-HLA-A*02 patients in FLAMINGO-01
- 170-180 clinical sites in US and Europe now on a unified protocol
- US protocol change has more than doubled pivotal-arm enrollment rate
- Non-HLA-A*02 patients, about 55% of the population, now eligible for enrollment
- Combined HLA analysis may support pursuit of approval in both HLA groups
Negative
- Regulatory feedback from UK and Canadian authorities on FLAMINGO-01 protocol is still pending
News Explained
The July 16 release adds that feedback from UK and Canadian regulators is still expected, leaving those jurisdictions as the named unresolved regulatory step for the combined FLAMINGO-01 enrollment design.
News Market Reaction – GLSI
In the Jul 16 session, GLSI declined 2.71%, reflecting a moderate negative market reaction. Argus tracked a peak move of +5.4% during that session. Argus tracked a trough of -22.1% from its starting point during tracking. Our momentum scanner triggered 22 alerts that day, indicating elevated trading interest and price volatility. Trading volume was above average at 1.9x the daily average, suggesting increased trading activity.
Data tracked by StockTitan Argus on the day of publication.
Key Figures
Historical Context
| Date | Event | Sentiment | 24h Move | Catalyst |
|---|---|---|---|---|
| Jul 09 | Trial supply approval | Positive | +3.7% | EMA approval to use commercially manufactured GP2 lot in FLAMINGO-01. |
| Jun 01 | Clinical data update | Positive | +8.9% | ASCO presentation of open-label immune response data in non-HLA-A*02 arm. |
| Jun 01 | Regulatory filing delay | Negative | +8.9% | Update on delayed Form 10-K and trial-linked accounts payable adjustments. |
| May 22 | Nasdaq notice | Negative | -0.9% | Nasdaq notice for late Form 10-Q, no immediate listing effect disclosed. |
| Apr 30 | Regulatory filing update | Neutral | +9.3% | Status of Form 10-K audit and unaudited cash balance disclosure. |
24h Move is the share-price change in the day after each event; other market factors may also have contributed.
Recent GLSI headlines linked to FLAMINGO-01 or GP2 have often coincided with positive next-day moves, including several strong gains on clinical and operational updates.
Key Terms
hla-a*02 medical
european medicines agency regulatory
interim analysis technical
statistical power technical
AI-generated analysis. How Rhea-AI works. Not financial advice.
STAFFORD, Texas, July 16, 2026 (GLOBE NEWSWIRE) -- Greenwich LifeSciences, Inc. (Nasdaq: GLSI) (the "Company"), a clinical-stage biopharmaceutical company focused on its Phase III clinical trial, FLAMINGO-01, which is evaluating GLSI-100, an immunotherapy to prevent breast cancer recurrences, today provided the following update on the combination of both HLA-A*02 and non-HLA-A*02 patients in FLAMINGO-01 in Europe.
All European and US Sites to Combine All Patients Independent of HLA Type in the Randomized Arms of FLAMINGO-01
The Company previously announced that US clinical sites started enrolling both HLA-A*02 and non-HLA-A*02 patients in the same randomized arms in FLAMINGO-01, based on the FDA's review of such protocol changes, effectively more than doubling the enrollment rate of the pivotal arm of the study. Non-HLA-A*02patients who represent about
The European Medicines Agency (EMA) has completed their review and will also allow the combination of both HLA-A*02 and non-HLA-A*02 patients in Europe. Thus, all 170-180 clinical sites in the US and Europe, are now operating under the same protocol and could continue enrolling up to the first interim analysis. Data can be analyzed by individual HLA types as well.
Additional feedback is expected from UK and Canadian regulators. The Company plans to provide updates regarding the resulting improved trial design, including a pathway for the Company to now pursue approval for both HLA-A*02 and non-HLA-A*02 patients using the increased statistical power of a combined analysis of the two patient groups together potentially doubling the market for GP2 by accelerating the clinical development of the non-HLA-A*02 population.
About FLAMINGO-01 Open Label Phase III Data
More than 1,300 patients have been screened with a current screen rate of approximately 800 patients per year. The 250 patient non-HLA-A*02 arm is now fully enrolled, where all patients received GLSI-100, which is 5 times more treated patients and recurrence rate data than the approximately 50 patients treated in the Phase IIb trial. The Primary Immunization Series (PIS), which includes the first 6 GLSI-100 injections over the first 6 months and is required to reach peak protection, is followed by 5 booster injections given every 6 months to prolong the immune response, thereby providing longer-term protection.
- In the non-HLA-A*02 arm, a preliminary analysis of recurrence rates after the PIS is completed shows an approximately 70
-80% reduction in recurrence rate. - This observation is trending similarly to the Phase IIb trial results and hazard ratio where HLA-A*02 patients were treated and where breast cancer recurrences were reduced up to
80% compared to a 20-50% reduction in recurrence rate by other approved products. - The immune response at baseline prior to any GLSI-100 treatment, the increasing immune response during the PIS, and the safety profile of non-HLA-A*02 patients is trending similarly to the HLA-A*02 arms of FLAMINGO-01 and to the Phase IIb study.
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- The AACR Meeting 2026 delayed-type-hypersensitivity (DTH) poster and the ASCO Meeting 2026 injection site reaction (ISR) poster can be seen and downloaded at the bottom of the Phase III clinical trial tab on the Company's website here.
- As shown in both posters the frequency of DTH and ISR reactions increased statistically significantly over time.
- As reported in Table 1 of each poster, each HLA-A type exhibited more frequent immune reactivity after treatment with GLSI-100 than at baseline.
- Baseline DTH reaction prior to any treatment suggests that GP2 may be a natural antigen and that GP2 specific T cells may exist in some patients prior to any treatment with GLSI-100. Baseline immune response to GP2 prior to any vaccination with GP2 was also observed in the Phase IIb trial and is being observed in the blinded randomized arms of FLAMINGO-01, where HLA-A*02 only patients are being vaccinated.
Analysis of the open label data from FLAMINGO-01 has been conducted in a manner that maintains the study blind. The open label recurrence rate, immune response, and safety data is based on the patients enrolled to date in FLAMINGO-01 and the data provided by the clinical sites so far, which is not completed or fully reviewed, and is thus preliminary. While comparing any preliminary FLAMINGO-01 data to the Phase IIb clinical trial data may be possible, these preliminary results are not a prediction of future results, and the results at the end of the study may differ.
About GLSI-100 Phase IIb Study
In the prospective, randomized, single-blinded, placebo-controlled, multi-center (16 sites led by MD Anderson Cancer Center) Phase IIb clinical trial of HLA-A*02 breast cancer patients, 46 HER2/neu 3+ over-expressor patients were treated with GLSI-100, and 50 placebo patients were treated with GM-CSF alone. After 5 years of follow-up, there was an
80% or greater reduction in metastatic breast cancer recurrence rate over 5 years of follow-up with a peak immune response at 6 months and well-tolerated safety profile.- The PIS elicited a potent immune response as measured by local skin tests and immunological assays.
About FLAMINGO-01 and GLSI-100
FLAMINGO-01 (NCT05232916) is a Phase III clinical trial designed to evaluate the safety and efficacy of Fast Track designated GLSI-100 (GP2 + GM-CSF) in HER2 positive breast cancer patients who had residual disease or high-risk pathologic complete response at surgery and who have completed both neoadjuvant and postoperative adjuvant trastuzumab based treatment. The trial is led by Baylor College of Medicine and currently includes US and European clinical sites from university-based hospitals and academic and cooperative networks with plans to open up to 170-180 sites globally.
About Breast Cancer and HER2/neu Positivity
One in eight U.S. women will develop invasive breast cancer over her lifetime, with approximately 300,000 new breast cancer patients and 4 million breast cancer survivors. HER2 (human epidermal growth factor receptor 2) protein is a cell surface receptor protein that is expressed in a variety of common cancers, including in
About Greenwich LifeSciences, Inc.
Greenwich LifeSciences is a clinical-stage biopharmaceutical company focused on the development of GP2, an immunotherapy to prevent breast cancer recurrences in patients who have previously undergone surgery. GP2 is a 9 amino acid transmembrane peptide of the HER2 protein, a cell surface receptor protein that is expressed in a variety of common cancers, including expression in
Forward-Looking Statement Disclaimer
Statements in this press release contain "forward-looking statements" that are subject to substantial risks and uncertainties. All statements, other than statements of historical fact, contained in this press release are forward-looking statements. Forward-looking statements contained in this press release may be identified by the use of words such as "anticipate," "believe," "contemplate," "could," "estimate," "expect," "intend," "seek," "may," "might," "plan," "potential," "predict," "project," "target," "aim," "should," "will," "would," or the negative of these words or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements are based on Greenwich LifeSciences Inc.'s current expectations and are subject to inherent uncertainties, risks and assumptions that are difficult to predict, including statements regarding the intended use of net proceeds from the public offering; consequently, actual results may differ materially from those expressed or implied by such forward-looking statements. Further, certain forward-looking statements are based on assumptions as to future events that may not prove to be accurate. These and other risks and uncertainties are described more fully in the section entitled "Risk Factors" in Greenwich LifeSciences' Annual Report on the most recent Form 10-K for the year ended December 31, 2025, and other periodic reports filed with the Securities and Exchange Commission. Forward-looking statements contained in this announcement are made as of this date, and Greenwich LifeSciences, Inc. undertakes no duty to update such information except as required under applicable law.
Company Contact
Snehal Patel
Investor Relations
Office: (832) 819-3232
Email: info@greenwichlifesciences.com
Investor & Public Relations Contact for Greenwich LifeSciences
Dave Gentry
RedChip Companies Inc.
Office: 1-800-RED CHIP (733 2447)
Email: dave@redchip.com
