GLSI News & Events

Greenwich LifeSciences presents the published abstract and poster from the ASCO annual meeting. The abstract is shown below. This is the second abstract and poster presented jointly with the Steering Committee of FLAMINGO-01 with statistically significant injection site reaction immune response data, with subgroup analysis by the most prevalent HLA types. In the non-HLA-A*02 open label arm where all patients were treated with GLSI-100, immune responses to GP2 were measured at baseline and over time using skin tests and ISRs. An ISR reaction, erythema or induration, was used to assess in vivo immune responses in patients. The diameter of the reaction was assessed 48-72 hours after injection but is not reported here. In this preliminary data analysis, there was a significant increase in percentage of patients experiencing an ISR reaction in vaccination 4, vaccination 5 or vaccination 6 compared to the baseline vaccination. There were 208 patients with both baseline vaccination and vaccination 4, 5 or 6 assessments. There was a significant increase in the percentage of patients experiencing erythema ISRs after the 4th, 5th or 6th vaccination compared to the ISRs from the 1st vaccination. In this preliminary analysis, the frequency of ISRs increased significantly from 20.2% of the patients experiencing an ISR after the first vaccination to 55.3% of the patients experiencing an ISR after the 4th, 5th or 6th vaccination, representing an increase of 2.7x or 174%. There was a significant increase in the percentage of patients experiencing induration ISRs after the 4th, 5th or 6th vaccination compared to the ISRs from the 1st vaccination. In this preliminary analysis, the frequency of ISRs increased significantly from 14.9% of the patients experiencing an ISR after the first vaccination to 34.6% of the patients experiencing an ISR after the 4th, 5th or 6th vaccination, representing an increase of 2.3x or 132%. As reported in Table 1, each HLA-A type exhibited more frequent immune reactivity with increased GLSI-100 vaccinations with frequency increasing by 60% to 280% over the frequency after the first vaccination. These results are consistent with the GP2 DTH results presented at AACR. A positive immune response is an indicator that the immune system has been activated against recurring cancer cells, potentially leading to the prevention of metastatic breast cancer. The company previously announced that in the non-HLA-A*02 arm, a preliminary analysis of recurrence rates after the Primary Immunization Series is completed shows an approximately 70%-80% reduction in recurrence rate. Thus, the immune response data is supporting the mechanism of action that reduces recurrences and prevents metastatic breast cancer. This statistically significant non-HLA-A*02 open label arm immune response data for both DTH and ISRs is trending similarly to the immune response data in the HLA-A*02 patients in the Phase IIb study and the HLA-A*02 arms of FLAMINGO-01. The study is ongoing and data collection and cleaning continue, while some patients may still be in their PIS vaccination phase, so final results may vary. The statistically significant increase in the incidence of ISR reactions over time found in this preliminary analysis of GLSI-100 treated non-HLA-A*02 patients shows that GLSI-100 treatment should not be limited to HLA-A*02 patients. Patients treated with GLSI-100 were increasingly able to mount an immune response to GP2 as evidenced in this preliminary data. Future investigations may explore the use of immune responses to assess correlation of DTH to ISRs, immunogenicity of GLSI-100 by specific HLA type, timing of boosters to sustain immunity, clinical site performance, and the discontinuation of treatment for non-responders.

Greenwich LifeSciences provided an update on its Form 10-K filing for the fiscal year ending December 31, 2025. "The Form 10-K for the fiscal year ending December 31, 2025, continues to be audited by our new auditor and we believe it is in the final approval steps. The Form 10-K also includes the 2024 audit that was previously audited by the prior auditor. As previously indicated, the accounts payable adjustments are related to the large global Phase III clinical trial underway and the unexpectedly large increase in screening and patient enrollment in Europe in 2024 and 2025. Both auditors in a dual auditor filing must agree in order to make timely filings, which did not occur in March or April, and such coordination is still required as part of the final approval steps. The Company believes that it did not contribute to the delays in filing and instead did everything possible to file on time. The Company provided the 10K filing information with large increases to accounts payable to the auditors for review in early February 2026 and requested and anticipated an early filing. The Company has further improved its accounts payable estimations using current clinical trial data in its financials for Form 10-Q for the period ending March 31, 2026. The Company believes that the accounts payable adjustments are not material to the Company or its investors and does not change the fundamentals of the Company. The shift in expenses does not change the cash balance or the net cash used in operating activities of the Company. As previously announced, the Company's ending cash balance as of March 31, 2026 is approximately $10.5 million, which the Company believes is an improvement over 2025 ending cash balances, and includes the retirement of over 75% of accounts payable for the fiscal year ending December 31, 2025. This $10.5 million cash balance is more than the 2025 net cash used in operating activities which is approximately $9.9 million. The above figures are unaudited and are subject to change following the completion of the Company's financial audit for the year ending December 31, 2025 and the review for the period ending March 31, 2026."

Greenwich LifeSciences announced that on April 16, the company received notification from Nasdaq notifying the company that, because it has not yet filed its annual report on Form 10-K for the fiscal year ended December 31, 2025, the company is not currently in compliance with Nasdaq Listing Rule 5250, which requires timely filing of periodic financial reports with the Securities and Exchange Commission. The notice has no immediate effect on the listing or trading of the company's common stock, which continues to trade on the Nasdaq Capital Market under the symbol (GLSI). The company plans to file its Form 10-K for the fiscal year ended December 31, 2025 as soon as possible, working with both of its auditors where each auditor is responsible for their own periods ending in 2024 and 2025.