Why Did GLSI Stock Surge 25% Today?

The company’s Board extended the lock-up on shares held by directors, officers, and pre-IPO investors through Sept. 30, 2026.

• During this period, insiders will be restricted from selling their shares unless the board decides otherwise.
• The lock-up helps align insiders with long-term shareholders while supporting the Phase III FLAMINGO-01 study of GLSI-100, CEO Snehal Patel said.
• GLSI shares have been on a rally since the company announced progress in the FLAMINGO-01 trial on December 15, gaining more than 130%.

Shares of Greenwich LifeSciences Inc. (GLSI) jumped 25% on Monday, to their highest since February 2022, after the company’s Board extended the lock-up period on shares held by directors, officers, and pre-IPO investors by six months, through Sept. 30, 2026 – roughly six years after the company’s initial public offering (IPO).

During this period, insiders will be restricted from selling their shares unless the board decides otherwise. Any sales after that date would still be limited under a structured “leak-out” plan.

Chief Executive Officer Snehal Patel said the longer lock-up helps align insiders with long-term shareholders while supporting the Phase III FLAMINGO-01 study of GLSI-100, an immunotherapy to prevent breast cancer recurrence.

GLSI shares have been on a rally since the company announced progress in the FLAMINGO-01 trial on December 15, gaining more than 130%.  The stock is on track to post its biggest monthly gain in five years.

FLAMINGO-01 Trial Progress

FLAMINGO-01 is a global Phase III study testing GLSI-100 in HER2-positive breast cancer patients following standard treatment. More than 1,000 patients have been screened, with enrollment continuing across U.S. and European sites, the company said. Around 140 sites are actively enrolling patients, with plans to expand further in 2026.

Preliminary data from the open-label non-HLA-A*02 arm, involving 250 treated patients, showed around 80% reduction in recurrence rates following the primary immunization series, which consists of six injections over six months. These early results appear consistent with findings from the company’s Phase IIb trial, though Greenwich cautioned that the data remains preliminary and subject to further review.

In its earlier Phase IIb trial, GLSI-100 demonstrated an 80% or greater reduction in metastatic breast cancer recurrences over five years in treated patients, with a strong immune response and a favorable safety profile. These results underpin the design and expectations of the ongoing Phase III study, the company added.

How Did Stocktwits Users React?

Retail sentiment on Stocktwits remained in the ‘extremely bullish’ territory over the past 24 hours, amid ‘extremely high’ message volumes. GLSI was among the top trending tickers on the platform at the time of writing.

One user believes that, given the large volume, a ‘big player’ could be buying in.

Year-to-date, GLSI has gained more than 120%.

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