J Urol

Metformin falls short in preventing metabolic syndrome during ADT, but shows metabolic benefits

November 5, 2025

Study details: The PRIME study was a multicenter, double-blind, randomized phase 3 trial evaluating metformin (850 mg BID) vs. placebo over 18 months in normoglycemic prostate cancer patients initiating androgen deprivation therapy (ADT) for at least 9 months. Primary endpoint was prevalence of metabolic syndrome (MS) at 18 months. The trial enrolled 166 patients (planned n = 300) before early termination due to drug supply issues.

Results: Metformin didn’t significantly reduce MS prevalence compared with placebo (55% vs. 68% at 18 months; p = 0.2). However, metformin led to statistically significant improvements in body weight, waist circumference, and HbA1c at multiple time points, suggesting metabolic benefit.

Clinical impact: While metformin failed to prevent MS in patients on ADT, its favorable effects on weight and glycemic control may support its use to mitigate ADT-related metabolic complications. Further studies with adequate power are needed to clarify its role in this setting.

Source:

Eigl BJ, et al. (2025, November 1). J Urol. A Randomized Phase 3 Trial of Metformin in Patients Initiating Androgen Deprivation Therapy as Prevention and Intervention of Metabolic Syndrome: The PRIME Study. https://pubmed.ncbi.nlm.nih.gov/40711960/