Carcinogenicity Risk Assessment Supports the Chronic Safety of Dapagliflozin, an Inhibitor of Sodium–Glucose Co-Transporter 2, in the Treatment of Type 2 Diabetes Mellitus

INTRODUCTION Dapagliflozin is a selective inhibitor of the sodium-glucose co-transporter 2 (SGLT2) that increases urinary glucose excretion to reduce hyperglycemia in the treatment of type 2 diabetes mellitus. A robust carcinogenicity risk assessment was undertaken to assess the chronic safety of dapagliflozin and SGLT2 inhibition. METHODS Genotoxicity potential of dapagliflozin and its metabolites was assessed in silico, in vitro, and in vivo. Dapagliflozin was administered daily by oral gavage to mice, rats, and dogs to evaluate carcinogenicity risks, including the potential for tumor promotion. SGLT2(-/-) mice were observed to evaluate the effects of chronic glucosuria. The effects of dapagliflozin and increased glucose levels on a panel of human bladder transitional cell carcinoma (TCC) cell lines were also evaluated in vitro and in an in vivo xenograft model. RESULTS Dapagliflozin and its metabolites were not genotoxic. In CD-1 mice and Sprague-Dawley rats treated for up to 2 years at ≥100× human clinical exposures, dapagliflozin showed no differences versus controls for tumor incidence, time to onset for background tumors, or urinary bladder proliferative/preneoplastic lesions. No tumors or preneoplastic lesions were observed in dogs over 1 year at >3,000× the clinical exposure of dapagliflozin or in SGLT2(-/-) mice observed over 15 months. Transcription profiling in Zucker diabetic fatty rats showed that 5-week dapagliflozin treatment did not induce tumor promoter-associated or cell proliferation genes. Increasing concentrations of glucose, dapagliflozin, or its primary metabolite, dapagliflozin 3-O-glucuronide, did not affect in vitro TCC proliferation rates and dapagliflozin did not enhance tumor growth in nude mice heterotopically implanted with human bladder TCC cell lines. CONCLUSION A multitude of assessments of tumorigenicity risk consistently showed no effects, suggesting that selective SGLT2 inhibition and, specifically, dapagliflozin are predicted to not be associated with increased cancer risk.