Greenwich LifeSciences Provides Global Update on FLAMINGO-01, Screening Over 1,000 Patients to Date

Rhea-AI Summary

Greenwich LifeSciences (Nasdaq: GLSI) provided a global update on its Phase III trial FLAMINGO-01 evaluating GLSI-100 to prevent breast cancer recurrence. The company has screened over 1,000 patients to date across 140 active sites (about 40 US sites and 100 EU sites).

Screening is progressing at ~150 patients per quarter (~600 per year). Management is considering continuing enrollment in both the HLA-A*02 and non-HLA-A*02 arms until interim analyses define appropriate arm sizes, and reports interest from additional countries to join the study.

Positive

• 1,000+ patients screened in FLAMINGO-01
• Screening rate ~150 patients/quarter (~600/year)
• 140 active sites (~40 US, ~100 EU) increasing enrollment capacity
• Interest from additional countries could expand enrollment

Negative

• Enrollment strategy for HLA-A*02 vs non-HLA-A*02 arms not finalized pending interim analyses

STAFFORD, Texas, Dec. 03, 2025 (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 global update on FLAMINGO-01.

Flamingo-01 Progress to Date

The Company has achieved a major milestone by screening over 1,000 patients in Flamingo-01, continuing its screening rate of approximately 150 patients per quarter or the equivalent of 600 patients per year in approximately 40 US sites and 100 EU sites for a total of 140 active sites. The Company is considering a strategy to continue enrolling in both the HLA-A*02 and non-HLA-A*02 arms until interim analyses are conducted and the appropriate size of each arm can be further assessed.

CEO Snehal Patel commented, "Reaching 1,000 screened patients confirms that the interest from doctors and patients is high. The clinical site start-up activities in Europe in 2025 have further increased the momentum in the study. We are also receiving interest from other countries to join FLAMINGO-01, driven by patient interest. The high screening rate will give the Company many options, including the opportunity to continue enrollment through multiple interim analyses, the potential to realize higher enrollment rates and event rates, and the potential to maximize indications by analyzing efficacy across multiple HLA types in larger patient populations."

About FLAMINGO-01 and GLSI-100

FLAMINGO-01 (NCT05232916) is a Phase III clinical trial designed to evaluate the safety and efficacy of 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 150 sites globally. In the double-blinded arms of the Phase III trial, approximately 500 HLA-A*02 patients will be randomized to GLSI-100 or placebo, and up to 250 patients of other HLA types will be treated with GLSI-100 in a third arm. The trial has been designed to detect a hazard ratio of 0.3 in invasive breast cancer-free survival, where 28 events will be required. An interim analysis for superiority and futility will be conducted when at least half of those events, 14, have occurred. This sample size provides 80% power if the annual rate of events in placebo-treated subjects is 2.4% or greater.

For more information on FLAMINGO-01, please visit the Company's website here and clinicaltrials.gov here. Contact information and an interactive map of the majority of participating clinical sites can be viewed under the "Contacts and Locations" section. Please note that the interactive map is not viewable on mobile screens. Related questions and participation interest can be emailed to: flamingo-01@greenwichlifesciences.com

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 75% of breast cancers at low (1+), intermediate (2+), and high (3+ or over-expressor) levels.

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 75% of breast cancers at low (1+), intermediate (2+), and high (3+ or over-expressor) levels. Greenwich LifeSciences has commenced a Phase III clinical trial, FLAMINGO-01. For more information on Greenwich LifeSciences, please visit the Company's website at www.greenwichlifesciences.com and follow the Company's Twitter at https://twitter.com/GreenwichLS.

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, 2024, 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

FAQ

How many patients has Greenwich LifeSciences (GLSI) screened in FLAMINGO-01 as of December 3, 2025?

The company has screened over 1,000 patients in FLAMINGO-01 as of December 3, 2025.

What is the current screening rate for GLSI's FLAMINGO-01 trial?

Screening is proceeding at approximately 150 patients per quarter, equivalent to about 600 patients per year.

How many active sites are enrolling patients in FLAMINGO-01 (GLSI) and where are they located?

FLAMINGO-01 has 140 active sites, roughly 40 in the US and 100 in the EU.

Will GLSI continue enrolling both HLA-A*02 and non-HLA-A*02 arms in FLAMINGO-01?

The company is considering continuing enrollment in both arms until interim analyses determine the appropriate size for each arm.

Does Greenwich LifeSciences (GLSI) expect to add more countries to FLAMINGO-01?

Yes; the company reports interest from other countries to join FLAMINGO-01 driven by patient interest.

What options does the high screening rate give GLSI for FLAMINGO-01?

High screening allows options including continuing enrollment through interim analyses, potentially higher enrollment and event rates, and analyzing efficacy across multiple HLA types.