Greenwich LifeSciences Insiders Extend Lock-up to Six Years in Bold Move

STAFFORD, TX – December 29, 2025 – In a move that has sent a powerful signal of confidence to Wall Street, clinical-stage biopharmaceutical company Greenwich LifeSciences, Inc. (NASDAQ: GLSI) announced today an extension of the lock-up period for its directors, officers, and pre-IPO investors. The new agreement pushes the restriction on selling shares to September 30, 2026, marking an unprecedented six-year commitment from the company's inception as a public entity.

The market responded with immediate enthusiasm, sending GLSI shares surging over 20% in trading today. The decision is being widely interpreted as a testament to the leadership's unwavering belief in the long-term success of its lead product candidate, GLSI-100, an immunotherapy currently in a pivotal Phase III clinical trial for preventing breast cancer recurrence.

An Unprecedented Vote of Confidence

Insider lock-up periods, typically lasting 90 to 180 days post-IPO, are standard practice designed to prevent market volatility. However, a voluntary extension to 72 months, or six years, is virtually unheard of in the volatile biotech sector. This commitment by Greenwich LifeSciences' insiders starkly contrasts with industry norms and is explicitly intended to align their interests with those of long-term shareholders.

This is not the first time the company has taken such a step. An earlier extension in March 2025 pushed the lock-up to March 2026. This latest move solidifies the message: insiders are committed for the long haul, tying their financial outcomes directly to the success of the ongoing FLAMINGO-01 Phase III trial. For investors, this level of insider conviction provides a powerful, non-verbal cue about the perceived potential of the company's core asset, suggesting that those with the most intimate knowledge of the science and data are willing to wait for a significant value inflection point.

The Science Driving the Strategy

At the heart of this corporate maneuver is GLSI-100, an immunotherapy designed to prevent the recurrence of breast cancer in HER2/neu positive patients. These patients have often completed grueling standard-of-care treatments, yet still face a persistent risk of the cancer returning. GLSI-100 aims to address this critical unmet need by training the patient's immune system to recognize and attack any remaining cancer cells that express the HER2 protein.

The company's confidence is rooted in compelling clinical data. An earlier Phase IIb trial showed an 80% or greater reduction in the recurrence rate over five years. Crucially, preliminary analysis from the currently enrolling FLAMINGO-01 Phase III trial is showing a similar trend. Data from the 250-patient open-label arm, which includes patients who don't fit the primary trial's genetic profile, indicates an approximate 80% reduction in recurrence after the initial six-month treatment series.

The FLAMINGO-01 trial is a large-scale, global effort, with over 1,000 patients screened and approximately 140 active sites. The U.S. Food and Drug Administration (FDA) has granted GLSI-100 a Fast Track designation, a status reserved for drugs that treat serious conditions and fill an unmet medical need. This designation could expedite the review process and bring the therapy to patients sooner if the trial proves successful. The Data Safety Monitoring Board has met twice in 2025, recommending the trial continue without modification and noting no serious adverse effects related to the immunotherapy.

Positioning in a Crowded Field

The HER2-positive breast cancer market is a multi-billion dollar arena dominated by giants and revolutionary treatments like trastuzumab (Herceptin) and the newer antibody-drug conjugate trastuzumab deruxtecan (Enhertu). The market, valued at over $10 billion in 2025, continues to see innovation. However, Greenwich LifeSciences is not aiming to replace these therapies but to complement them.

GLSI-100 is positioned as a preventative measure for patients who have already completed these primary treatments. The threat of recurrence, particularly metastatic disease, remains a significant source of anxiety for patients and a challenge for clinicians. While existing therapies have dramatically improved outcomes, a substantial portion of patients still experience relapse. If GLSI-100 can successfully and safely reduce that recurrence rate by the 80% suggested in early data, it would carve out a unique and highly valuable niche in the treatment paradigm, potentially becoming a new standard of care for post-treatment management.

Strategic Flexibility Remains Key

While the six-year lock-up is a powerful statement, it is not absolute. The company has been transparent that the Board of Directors retains the authority to modify the agreement. The terms could be altered, or a managed "leak-out" plan could be implemented, particularly in the event of significant milestones.

The company specifically cited positive interim trial analyses or strategic transactions, such as a partnership or acquisition, as potential triggers for adjusting the lock-up. This provides the company with crucial flexibility. Should the FLAMINGO-01 trial deliver overwhelmingly positive interim results, or should a major pharmaceutical company express interest in a partnership, the board has the power to allow for controlled liquidity for its long-standing insiders. This structure balances the strong signal of commitment with the practical need for strategic maneuverability, ensuring the company can act decisively on opportunities that may arise from its clinical progress. For now, all eyes remain on the progress of the FLAMINGO-01 trial, which holds the key to the company's future and the hopes of many patients.