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 <1% per Year in Non-HLA-A*02 Patients Treated with GLSI-100, Following Completion of Primary Immunization Series (PIS)



     
  • This <1% Annual Recurrence Rate Observed in Non-HLA-A*02 Patients is Statistically Significantly Smaller Than a 4% Annual Recurrence Rate Over a Similar Time Period Observed in the Katherine Study (Kadcyla Treated Arm) Yielding an Approximately 70-80% Reduction in Recurrence Rate as Explained Below

     

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 <1% recurrence rate per year of these 250 treated patients after completing the PIS was compared to the expected historical recurrence rate per year reported for a similar population in the Katherine study who received TDM1 (Kadcyla), which is about 4% recurrences per year or higher in the initial years of the Katherine study. The majority of the treated patients in FLAMINGO-01 also received TDM1 followed by GLSI-100.



     
  • 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 < 0.005). This preliminary data will continue to be updated and cleaned, so future and final results may vary. Future updates may be presented at upcoming conferences.

     
  • 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.