Greenwich Insiders Lock Shares for 6 Years on Promising Cancer Drug Data

STAFFORD, TX – December 29, 2025 – In a move that sent a powerful signal of long-term conviction to Wall Street, clinical-stage biopharmaceutical company Greenwich LifeSciences, Inc. announced it has extended the lock-up period for shares held by its directors, officers, and pre-IPO investors. The decision, which pushes the restriction to September 30, 2026, was met with a surge in the company’s stock price, as investors digested the implications of this unusual commitment tied to the firm's promising breast cancer immunotherapy, GLSI-100.

The announcement caused shares of Greenwich LifeSciences (Nasdaq: GLSI) to jump nearly 20% in the following trading session, with an intraday peak over 40%, on trading volume almost three times its daily average. This market enthusiasm reflects a view that the company's leadership is betting firmly on the future success of its lead drug candidate currently in a pivotal Phase III trial.

An Unprecedented Vote of Confidence

The extended lock-up now totals approximately 72 months, or six years, from the company’s initial public offering. This duration is a significant departure from standard industry practice, where insider lock-up agreements typically last for 180 days. In the volatile biopharma sector, where clinical trial outcomes can make or break a company, such a prolonged commitment is considered a rarity and a profound statement of insider belief in a company's long-term value proposition.

During this period, top executives, board members, and early investors are prohibited from selling their shares. According to the company, this aligns their financial interests directly with those of long-term public shareholders who are banking on the successful development and commercialization of GLSI-100.

CEO Snehal Patel commented in the official release, "This unprecedented 6 years lock-up is controlled by the Board and is designed to align the locked-up shareholders with the Company’s long term investors and to support the FLAMINGO-01 Phase III trial."

This lock-up, however, is not entirely inflexible. The Board of Directors retains the authority to modify or terminate the agreement at any time. Should they choose to do so, they could implement a structured "leak-out" plan to allow for the orderly and gradual sale of shares, or a 10b5-1 trading plan, which permits insiders to establish a pre-arranged selling schedule. This built-in discretion provides a balance between demonstrating long-term commitment and retaining the flexibility to adapt to future events, such as a strategic partnership or acquisition.

Fueling the Optimism: Promising Clinical Data

The foundation for this extraordinary insider confidence lies in the encouraging data emerging from the company's clinical program for GLSI-100. The immunotherapy is designed to prevent the recurrence of breast cancer in HER2-positive patients who have already completed standard-of-care treatments but remain at high risk.

The ongoing Phase III trial, known as FLAMINGO-01, is the centerpiece of the company's efforts. In a significant update accompanying the lock-up news, Greenwich LifeSciences revealed preliminary data from a specific arm of this study. The analysis focused on 250 non-HLA-A*02 patients, all of whom received GLSI-100 in an open-label setting. The results showed an approximate 80% reduction in the breast cancer recurrence rate for patients who completed the initial six-month course of treatment.

This preliminary finding is particularly compelling because it closely mirrors the results from the company’s earlier, successful Phase IIb trial. In that study, patients treated with GLSI-100 saw an 80% or greater reduction in cancer recurrences over a five-year follow-up period, establishing a strong scientific basis for the current late-stage trial. The consistency between the Phase IIb and preliminary Phase III data suggests the treatment's effect is robust across different patient populations.

The U.S. Food and Drug Administration has already granted Fast Track designation to GLSI-100, a status designed to facilitate the development and expedite the review of drugs that treat serious conditions and fill an unmet medical need. This designation allows for more frequent communication with the FDA and could potentially shorten the timeline to market if the FLAMINGO-01 trial proves successful. The trial itself has made substantial progress, with over 1,000 patients screened and the 250-patient open-label arm now fully enrolled. An independent Data Safety Monitoring Board has twice recommended the study continue without modification.

The Biotech Tightrope: Balancing Confidence and Capital

While the clinical data and insider commitment paint a rosy picture, Greenwich LifeSciences faces the financial realities common to many clinical-stage biotech firms. With no commercial products, the company generates no significant revenue and relies on external financing to fund its operations and expensive late-stage clinical trial.

According to recent financial filings, the company has a cash burn rate of approximately $7 million annually and has reported net losses in recent years. This has led to disclosures noting "substantial doubt regarding the company's ability to continue as a going concern without additional financing." To bridge this gap, Greenwich LifeSciences has been utilizing an at-the-market (ATM) financing facility, raising approximately $6.5 million in 2025 by selling new shares directly into the market.

In this context, the extended lock-up serves a dual strategic purpose. On one hand, it is a powerful marketing tool, demonstrating insider faith that can attract new investors and support the stock price. On the other, by preventing a large volume of insider shares from flooding the market, it helps maintain price stability, which is critical for the effectiveness of its ATM financing strategy. It reassures the market that the company's leaders are not looking for a quick exit but are invested in seeing the FLAMINGO-01 trial through to its conclusion.

Carving a Niche in a Crowded Field

The potential market for an effective breast cancer therapy is immense. The HER2-positive breast cancer market alone is valued at over $10 billion and is projected to grow steadily. This space is currently dominated by highly effective treatments from major pharmaceutical companies, including monoclonal antibodies like Herceptin and advanced antibody-drug conjugates like Enhertu.

However, Greenwich LifeSciences is not aiming to displace these blockbuster drugs. Instead, GLSI-100 is being developed to address a critical unmet need: preventing the cancer from coming back. It is intended for patients who have already undergone surgery and completed adjuvant treatments, including Herceptin-based therapies. For the one in eight women who will develop invasive breast cancer, the fear of recurrence can be constant.

If the FLAMINGO-01 trial confirms the dramatic reduction in recurrence rates seen in earlier data, GLSI-100 could establish a new standard of care in a well-defined niche. By complementing existing treatments rather than competing with them directly, the immunotherapy could become an essential final step in the treatment journey for a significant population of high-risk breast cancer survivors, offering them a new layer of protection and peace of mind. The company's strategy, underpinned by its leadership's long-term financial commitment, is a calculated gamble on filling this crucial gap in cancer care.