Renal tubular and adrenal medullary tumors in the 2-year rat study with canagliflozin confirmed to be secondary to carbohydrate (glucose) malabsorption in the 15-month mechanistic rat study

Abstract

During preclinical development of canagliflozin, an SGLT2 inhibitor, treatment-related pheochromocytomas, renal tubular tumors (RTT), and testicular Leydig cell tumors were reported in the 2-year rat toxicology study.In a previous 6-month rat mechanistic study, feeding a glucose free diet prevented canagliflozin effects on carbohydrate malabsorption as well as the increase in cell proliferation in adrenal medulla and kidneys, implicating carbohydrate malabsorption as the mechanism for tumor formation.In this chronic study male Sprague-Dawley rats were dosed orally with canagliflozin at high dose-levels (65 or 100 mg/kg/day) for 15 months and received either a standard diet or a glucose-free diet. Canagliflozin-dosed rats on standard diet showed presence of basophilic renal tubular tumors (6/90) and an increased incidence of adrenal medullary hyperplasia (35/90), which was fully prevented by feeding a glucose-free diet (no RTT's; adrenal medullary hyperplasia in ≤5/90).These data further confirm that kidney and adrenal medullary tumors in the 2-year rat study were secondary to carbohydrate (glucose) malabsorption and were not due to a direct effect of canagliflozin on these target tissues.