Using metformin in combination with standard of care (SOC) for high-risk locally advanced or metastatic hormone-sensitive prostate cancer (mHSPC) may improve outcomes in selected patients, according to investigators.
In a randomized controlled trial (RCT), patients who received the combination therapy experienced a significant delay in the development of castration-resistant disease compared with patients who received SOC alone, a team led by Mohamed A. ELbaiomy, MD, of Mansoura University in Mansoura, Egypt, reported in Urologic Oncology.
The trial included 124 patients randomly assigned to receive metformin 850 mg twice daily plus SOC (androgen deprivation therapy [ADT] or chemotherapy) or SOC alone. The primary endpoint was castration-resistant prostate cancer-free survival (CRPC-FS).
Over a median follow-up of 22 months, the metformin group had significantly longer median CRPC-FS compared with the SOC group (29 vs 20 months).
The investigators found a beneficial effect of metformin among some subgroups. For example, among patients with high-risk locally advanced disease, the median CRPC-FS was not reached in the metformin arm and 25 months in the SOC arm. Among patients with metastatic low-tumor-volume disease, the median CRPC-FS was not reached in the metformin arm and 15 months in the SOC arm. CRPC-FS did not differ significantly between study arms among patients with metastatic high-tumor-volume disease.
The study arms did not differ significantly with regard to overall survival and PSA response.
Metformin did not show significant adverse events except self-limited diarrhea in 3 patients, according to the investigators.
Dr ELbaiomy and colleagues said that to the best of their knowledge, “our study is the first RCT that confirmed that metformin use in combination with ADT prolonged the CRPC-FS in HSPC.”
Alghandour R, Ebrahim MA, Elshal AM, et al. Repurposing metformin as anticancer drug: Randomized controlled trial in advanced prostate cancer (MANSMED). Urol Oncol. Published online June 22, 2021. doi:10.1016/j.urolonc.2021.05.020