At a median follow-up time of 18 months, the median time to progression to CRPC in the standard of care arm was 20 months (95% CI 16-24) and 29 months in the standard of care plus metformin arm (95% CI 25-33). This difference was statistically significant with a p-value of 0.01.
When comparing time to progression in either localized disease or nodal positive disease, the metformin group had a statistically significantly longer time to progression to CRPC (HR 0.35 for progression in localized disease).
No statistically significant difference in overall survival was noted between the two arms with the current follow-up window. Side effects between the two arms were comparable, likely due to androgen deprivation therapy, with the exception of grade 2 diarrhea occurring in the metformin arm. Dr. ALGhandour concluded that metformin may be beneficial in both high-risk localized prostate cancer and metastatic castration-sensitive low-volume prostate cancer, but further confirmation is required. A phase 3 trial is currently ongoing and is expected to be reported out by 2024.
Presented by: Reham ALGhandour, MD, PhD, Medical Oncologist at the Oncology Center, Mansoura University, Egypt
Written by: Alok Tewari, MD, PhD, Medical Oncologist at the Dana-Farber Cancer Institute, at the 2020 European Society for Medical Oncology Virtual Congress (#ESMO20), September 19th-September 21st, 2020.