Greenwich LifeSciences delays first-quarter report, expects to file by May 20, 2025

The late quarterly report

Greenwich LifeSciences, Inc. (GLSI) filed a Form 12b-25 notice dated May 15, 2025, saying it cannot file its quarterly report for the three months ended March 31, 2025 without unreasonable effort and expense. The notice is signed by chief executive Snehal Patel. The company is based in Stafford, Texas.

The company expects to file the report by May 20, 2025, within the five calendar days that Rule 12b-25 allows. The notice says the company does not expect a significant change in results from the prior-year period, and that all other periodic reports for the preceding 12 months have been filed.

The notice gives no reason beyond the effort and expense language. It gives no revenue, loss or cash figure.

The lead program

Greenwich's focus is Flamingo-01, a Phase III trial of GLSI-100, an immunotherapy meant to prevent breast cancer recurrence. GLSI-100 pairs GP2, a nine-amino-acid transmembrane peptide of the HER2/neu protein, with GM-CSF, the immune adjuvant also sold as sargramostim and Leukine. The trial is designed to evaluate patients with HER2/neu-positive disease who have residual disease or a high-risk pathologic complete response at surgery, after completing neoadjuvant and adjuvant trastuzumab-based treatment.

The company says it is expanding Flamingo-01 into Europe, with plans to open up to 150 sites globally.

GP2 is injected intradermally, mixed with GM-CSF at the time of dosing. Patients receive 11 injections in total: six primary injections, one a month over six months, followed by five boosters every six months. Dosing starts in the second year after a first year of Herceptin treatment and continues through year four.

The benchmark drugs

The business section sets GP2 against Herceptin and Kadcyla. It says that in the adjuvant setting, Herceptin reduces recurrence rates by approximately 50%, from 25% to 12%. It says Kadcyla reduces recurrence by 50%, from 22% to 11%, in the neoadjuvant setting.

The company says that "we believe that GP2 may be effective in safely addressing the 50% of recurring patients who do not respond to either Herceptin or Kadcyla". That is a belief, not a trial result. The section cites preclinical studies showing that T cells sensitized against the GP2 peptide recognize HER2/neu-expressing tumors. Preclinical work does not show that patients recur less often.

The company also says HER2/neu is expressed in 75% of breast cancers at low, intermediate and high levels. That describes the target, not how many patients a drug would help.

Supply and approval limits

GM-CSF is approved for sale in the United States. In other countries it is available on a named patient basis through a specialized company. The business section says Greenwich depends on one manufacturer for lyophilized GM-CSF in its ongoing GP2 trials and in any future commercial supply. The manufacturer could also register GM-CSF elsewhere, but the section says that is only a possibility.

The immunotherapy field is described as new, and the section says the approach aims to stimulate the body's own immune system against cancer cells. The company does not claim a result for Flamingo-01 in this section.

What the filing does not say

The notice gives no quarterly figures, and the business section gives no financial data. Readers therefore have no current revenue, loss or cash position for the first quarter of 2025 from the notice, and no trial result from the business section.

What comes next

Greenwich expects to file its quarterly report by May 20, 2025. It says it is expanding Flamingo-01 into Europe and plans up to 150 sites globally. The timing of any trial result is not given in these documents.

The company's first-quarter financial position will not be clear until the report is filed.

Report an error

Companies in this story

GLSIGreenwich LifeSciences, Inc.NASDAQ · United StatesOpen the starter desk