Greenwich LifeSciences Provides Global Update on FLAMINGO-01

STAFFORD, Texas, April 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.

The Company recently confirmed that the preliminary HLA prevalence, safety, and immune response data in FLAMINGO-01 patients is trending as expected in both HLA-A02 and non-HLA-A02 arms. The non-HLA-A02 arm was expanded to 250 patients in 2024 with approval from both EU and US regulators. With the new preliminary positive immune response data in these patients, further changes are being considered, including the potential to transform the non-HLA-A02 open label third arm into effectively a second Phase III trial which could lead to multiple pathways for marketing approval of GLSI-100 and a larger market potential.

In Q1 2025, the Company achieved its highest screening rate of over 150 patients per quarter or the equivalent of 600 patients per year in 40 US sites and 77 EU sites for a total of 117 active sites. In addition, 30 sites in the EU are planned to be activated in 2025 with the potential for another 10 sites to be approved and added in additional EU countries, bringing the total potential sites to over 150 sites globally. Once these sites are activated, the Company is considering a strategy to continue enrolling in both of the HLA-A02 and non-HLA-A02 arms until an interim analysis is conducted and the appropriate size of each arm can be further assessed.

Approximately 40 US clinical sites with 134 locations, including sites in the US Oncology/Sarah Cannon network, are currently recruiting patients and are listed below and atwww.clinicaltrials.gov/study/NCT05232916. Many of the sites are prominent teaching hospitals, including Yale, Johns Hopkins, Harvard, Huntsman, Moffitt, Stanford, UCSF, UCLA, UCSD, UT Southwestern, UT San Antonio, Columbia, Northwestern, Washington University, Thomas Jefferson, Stony Brook, and Baylor, which is the lead site.

In early 2024, the expansion of Flamingo-01 into 5 EU countries was approved by European regulators. Since that time, 77 clinical trial sites have been activated, and study recruitment is well underway in Spain (29), France (17), Germany (18), Italy (9), and Poland (4).

European academic networks in each country are participating in Flamingo-01 and are listed below. These networks represent the largest oncology focused hospitals and centers in Europe, where breast cancer leaders work in a collaborative manner to help advance promising therapies. The networks hold annual scientific meetings where Flamingo-01 has been introduced and where the Company has presented in the past.

GEICAM is the leading group in breast cancer research in Spain and currently consists of more than 900 experts, who work in more than 200 centers throughout Spain. Since its establishment in 1995, GEICAM has carried out more than one hundred studies in which more than 66,000 women and men have participated.

UCGB or Unicancer is the federation of French comprehensive cancer centers, a major player in cancer research and a network of 20 private, non-profit healthcare centers specialized in oncology, brought together in a health cooperation group.

GBG Forschungs GmbH is one of the world's leading breast cancer research institutes that works together with the academic study group German Breast Group (GBG). With more than 67,000 study participants and 3,500 new patients per year, GBG is the largest breast cancer study group in Germany, consisting of more than 1,000 doctors in over 800 centers.

GIM (Gruppo Italiano Mammella) is a cooperative Italian network for breast cancer research and therapy. GIM brings together over 150 participating centers and around 500 investigators.

The Steering Committee is now comprised of the following experts in the field of breast cancer oncology representing prominent teaching hospitals in the US and 4 of the largest breast oncology networks in the US, Germany, France, and Spain:

CEO Snehal Patel commented, "Based on the high quarterly screening rate, the current level of interest in the FLAMINGO-01 trial is very high. The Company spent considerable time in Europe this past year training and activating all 77 sites. As these are the largest countries in Europe and the sites are distributed near large population centers, we hope to give as many patients as possible an opportunity to participate in the study. The prestigious sites participating in the study and the prominent KOLs at these sites and on our steering committee have helped to further validate the promise of GLSI-100 and have created momentum that is increasing patient awareness of the Phase IIb results and interest in participating in FLAMINGO-01."

Mr. Patel further added, "With the preliminary analysis of open label data of the Phase III trial complete, we will continue to analyze the open label data, potentially leading to future publications. We will also try to improve the conduct and design of the study with the ultimate goal to reproduce the Phase IIb results, if possible, and to prepare a treatment process that can be easily commercialized. To that end, we are also giving much consideration to the commercial manufacturing, packaging, and distribution of GLSI-100 and have been developing our manufacturing and regulatory strategy for both the US and Europe in parallel to conducting the clinical trial. Our patent strategy includes filing our own patent claims to potentially further extend the patent life of GLSI-100 in addition to the current 12 years of biological exclusivity that GLSI-100 will be eligible for in the US."

Patients who are interested in participating in the Flamingo-01 Phase III clinical trial can learn more about the study atwww.clinicaltrials.gov/study/NCT05232916. Each clinical trial site location is listed on the website under "Contacts and Locations" with a new feature showing each site on a map. Patients should contact a participating clinical trial site near them orFlamingo-01@GreenwichLifeSciences.comfor screening. The current listing of US sites from the clinicaltrials.gov website with email contact information for some sites is shown below and will be continually updated during the trial.

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 clinical sites from university-based hospitals and cooperative networks with plans to expand into Europe and 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 websitehereand clinicaltrials.govhere. 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

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.

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 atwww.greenwichlifesciences.comand follow the Company's Twitter athttps://twitter.com/GreenwichLS.

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 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.