Pathogenesis of Renal Injury and Gene Expression Changes in the Male CD-1 Mouse Associated with Exposure to Empagliflozin.

An increased incidence of renal tubular adenomas and carcinomas was identified in the 2-year CD-1 mouse carcinogenicity study with empagliflozin (sodium-glucose transporter 2 inhibitor) in high dose (1,000 mg/kg/day) male mice. A 13-week mouse renal investigative pathogenesis study was conducted with empagliflozin to evaluate dose dependency and temporal onset of nonneoplastic degenerative/regenerative renal tubular and molecular (genes, pathways) changes which precede neoplasia. Male and female CD-1 mice were given daily oral doses of 0, 100, 300, or 1,000 mg/kg/day (corresponding carcinogenicity study dose levels) for 1, 2, 4, 8, or 13 weeks. The maximum expected pharmacology with secondary osmotic diuresis was observed by week 1 at ≥100 mg/kg/day in both genders. Histopathologic kidney changes were first detected after 4 weeks of dosing in the male 1,000 mg/kg/day dose group, with progressive increases in the incidence and/or number of findings in this dose group so that they were more readily detected during weeks 8 and 13. Changes detected starting on week 4 consisted of minimal single-cell necrosis and minimal increases in mitotic figures. These changes persisted at an increased incidence at weeks 8 and 13 and were accompanied by minimal to mild tubular epithelial karyomegaly, minimal proximal convoluted tubular epithelial cell hyperplasia, and a corresponding increase in Ki-67-positive nuclei in epithelial cells of the proximal convoluted tubules. There were no corresponding changes in serum chemistry or urinalysis parameters indicative of any physiologically meaningful effect on renal function and thus these findings were not considered to be adverse. Similar changes were not identified in lower-dose groups in males nor were they present in females of any dose group. RNA-sequencing analysis revealed male mouse-specific changes in kidney over 13 weeks of dosing at 1,000 mg/kg/day. Treatment-related changes included genes and pathways related to p53-regulated cell cycle and proliferation, transforming growth factor ß, oxidative stress, and renal injury and the number of genes with significant expression change dramatically increased at week 13. These treatment-related changes in genes and pathways were predominant in high-dose males and complemented the observed temporal renal tubular changes. Overall, these mouse investigative study results support the role of early empagliflozin-related degenerative/regenerative changes only observed in high-dose male CD-1 mice as a key contributing feature to a nongenotoxic mode of renal tumor pathogenesis.

Nonclinical safety of the sodium-glucose cotransporter 2 inhibitor empagliflozin.

Empagliflozin, a selective inhibitor of the renal tubular sodium-glucose cotransporter 2, was developed for treatment of type 2 diabetes mellitus. Nonclinical safety of empagliflozin was studied in a battery of tests to support global market authorization. Safety pharmacology studies indicated no effect of empagliflozin on measures of respiratory or central nervous system function in rats or cardiovascular safety in telemeterized dogs. In CD-1 mouse, Wistar Han rat, or beagle dogs up to 13, 26, or 52 weeks of treatment, respectively, empagliflozin exhibited a toxicity profile consistent with secondary supratherapeutic pharmacology related to glucose loss and included decreased body weight and body fat, increased food consumption, diarrhea, dehydration, decreased serum glucose and increases in other serum parameters reflective of increased protein catabolism, gluconeogenesis, and electrolyte imbalances, and urinary changes such as polyuria and glucosuria. Microscopic changes were consistently observed in kidney and included tubular nephropathy and interstitial nephritis (dog), renal mineralization (rat) and tubular epithelial cell karyomegaly, single cell necrosis, cystic hyperplasia, and hypertrophy (mouse). Empagliflozin was not genotoxic. Empagliflozin was not carcinogenic in female mice or female rats. Renal adenoma and carcinoma were induced in male mice only at exposures 45 times the maximum clinical dose. These tumors were associated with a spectrum of nonneoplastic changes suggestive of a nongenotoxic, cytotoxic, and cellular proliferation-driven mechanism. In male rats, testicular interstitial cell tumors and hemangiomas of the mesenteric lymph node were observed; both tumors are common in rats and are unlikely to be relevant to humans. These studies demonstrate the nonclinical safety of empagliflozin.