STAFFORD, Texas - Greenwich LifeSciences Inc. (NASDAQ:GLSI) presented data today from its Phase III clinical trial FLAMINGO-01 at the ASCO Annual Meeting 2026, according to a press release statement. The stock closed at $26.18, reflecting strong investor interest in the company’s breast cancer immunotherapy program, with shares up 166% over the past year and 218% in the last six months.
The company presented preliminary immune response data from 247 patients in the non-HLA-A02 open label arm of the trial, where all patients received GLSI-100, an immunotherapy treatment for breast cancer. The treatment combines GP2, a nine amino acid peptide, with GM-CSF.
The data showed injection site reactions increased over time. The percentage of patients experiencing erythema reactions rose from 20.2% after the first vaccination to 55.3% after the fourth, fifth or sixth vaccination (p < 0.001). Induration reactions increased from 14.9% to 34.6% over the same period (p < 0.001). The analysis included 208 patients with both baseline and later vaccination assessments.
FLAMINGO-01 is a Phase III trial evaluating GLSI-100 in HER2-positive breast cancer patients who had residual disease or high-risk pathologic complete response after neoadjuvant and adjuvant trastuzumab-based treatment. The trial includes approximately 140 sites in the United States and Europe.
The treatment protocol involves six intradermal injections over six months, followed by five booster injections over 2.5 years. The trial is designed to detect a hazard ratio of 0.3 in invasive breast cancer-free survival, requiring 28 events. An interim analysis will be conducted at 14 events.
The company stated that more than 1,300 patients have been screened, with the 250-patient non-HLA-A02 arm now fully enrolled. The study is ongoing and data collection continues.
The abstract was co-authored by a steering committee including researchers from Baylor College of Medicine, Institut Curie, Northwestern University, and other institutions.Despite the company’s current lack of profitability, with losses of $1.46 per share over the last twelve months, analysts remain optimistic. The consensus rating stands at "Strong Buy," with price targets ranging from $45 to $50. InvestingPro analysis suggests the stock may be overvalued at current levels, though the company maintains liquid assets that exceed short-term obligations. Investors seeking deeper insights can access 5 additional ProTips and comprehensive financial metrics on the InvestingPro platform.
In other recent news, Greenwich LifeSciences has delayed its Form 10-K filing for the fiscal year ending December 31, 2025, due to coordination requirements between two auditors. The company anticipates completing the audit and filing the report by the end of May, alongside the filing of its Form 10-Q for the period ending March 31, 2026. Additionally, Greenwich LifeSciences received a noncompliance notice from Nasdaq for failing to file its Quarterly Report on time. The company also reported a cash balance of approximately $10.5 million as of March 31, 2026, with its financing vehicle raising more funds than its cash burn rate for the first quarter.
In clinical developments, Greenwich LifeSciences announced positive results from its GLSI-100 vaccine trial, which showed a stronger immune response in patients. This trial is part of the late-stage FLAMINGO-01 study, focusing on preventing breast cancer recurrence. These recent developments highlight the company’s ongoing efforts in both financial and clinical areas.
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