Greenwich Lifesciences' Preliminary Update Shows A Continued Reduction In The Recurrence Rate In The Fully Enrolled, 250-patient, Open-label Non-HLA-A*02 Arm Of FLAMINGO-01

Greenwich LifeSciences, Inc. (NASDAQ:GLSI) (the "Company"), a clinical-stage biopharmaceutical company focused on its Phase III clinical trial, FLAMINGO-01, which is evaluating GLSI-100, an immunotherapy to prevent breast cancer recurrences, today provided a preliminary update showing a continued reduction in the recurrence rate in the fully enrolled, 250 patient, open label non-HLA-A*02 arm of FLAMINGO-01.6 Months of Additional Patient Data Since Last Update Shows Recurrence Rate of This The non-HLA-A*02 arm does not have a direct placebo comparator arm, thus a Kaplan Meier survival analysis is not possible, and the following method was used:The As of this data cut, the current recurrence rate of the non-HLA-A*02 patients treated with GLSI-100, following completion of the PIS over an average of 1.2 years of patient exposure, is statistically significantly smaller than a 4% annual recurrence rate over a similar time period observed in the Katherine study (0.7% versus 4% annual recurrence rate over 1.2 patient-years, 83% reduction in recurrence rate, Chi Square, p This observation is trending similarly to the Phase IIb trial results and hazard ratio where HLA-A*02 patients were treated and where breast cancer recurrences were reduced up to 80% compared to a 20-50% reduction in recurrence rate by other approved products. Additional information about the non-HLA-A*02 arm follows:Virtually all of the non-HLA-A*02 patients have completed the primary immunization series, which is the first 6 monthly vaccinations in the study. Every 6 months approximately 110 patient-years are added to the non-HLA-A*02 patient data base. Enhertu (T-DXd) treated patients can be enrolled in FLAMINGO-01. In the future, if Enhertu is approved for high risk patients in the adjuvant setting, more Enhertu treated patients could be enrolled in FLAMINGO-01 and may recur at a lower rate than if treated with Kadcyla. The recurrence rate assumptions in the design of FLAMINGO-01 include this possibility as well as other potential improvements in standard of care. Analysis of the open label data from FLAMINGO-01 has been conducted in a manner that maintains the study blind. The open label recurrence rate, immune response, and safety data is based on the patients enrolled to date in FLAMINGO-01 and the data provided by the clinical sites so far, which is not completed or fully reviewed, and is thus preliminary. While comparing any preliminary FLAMINGO-01 data to the Phase IIb clinical trial data may be possible, these preliminary results are not a prediction of future results, and the results at the end of the study may differ.