Impact of Antidiabetic Medication on Therapy Outcomes in Metastatic Urothelial Cancer Patients Receiving Enfortumab Vedotin Monotherapy

Abstract

Objectives: The aim of this study was to assess the association of diabetes mellitus and its medications with overall response (ORR) and mortality or cancer-specific survival (CSS) in patients with metastatic urothelial cancer receiving enfortumab vedotin monotherapy. Methods: This multicentre retrospective cohort study was designed according to the guide lines for the synthesis of qualitative research (ENTREQ). Eligible patients were adults (≥18) years treated with enfortumab vedotin monotherapy for metastatic urothelial cancer between June 2024 and January 2025. A total of 125 patients were reported across 11 centres. Results: The cohort included 93 males (74.4%) and 32 females (25.6%), with a mean age of 68.3 years (SD 9.3). The primary tumour site was the bladder in 109 (87.2%) cases and the upper tract (UTUC) in 16 (12.8%) cases. Interestingly, medication with metformin was significantly associated with cancer-specific mortality (37.9% versus 77.8%; p = 0.019), while patients with insulin-dependent diabetes mellitus had a significantly better CSS (Log Rank = 0.004). Upon comparing only patients who already had diabetes mellitus and then received anti-diabetic medication, there was a significant association between patients with diabetes mellitus receiving metformin and a worse 3-month ORR (80.0% versus 55.6%; p = 0.039). Regarding the subpopulation of UTUC, cancer-specific mortality was signif icantly associated with metformin medication (p = 0.033). Conclusions: Despite recent reports that metformin has protective effects in urothelial cancer, our findings suggest that metformin use may be linked to worse responses and survival outcomes in patients treated with enfortumab vedotin monotherapy. Further research, particularly translational research into the underlying diabetic and pharmacologic pathways, is warranted.