13 NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenicity studies have not been conducted with temsirolimus. However, sirolimus, the major metabolite of temsirolimus in humans, was carcinogenic in mice and rats. The following effects were reported in mice and/or rats in the carcinogenicity studies conducted with sirolimus: lymphoma, hepatocellular adenoma and carcinoma, and testicular adenoma.
Temsirolimus was not genotoxic in a battery of in vitro (bacterial reverse mutation in Salmonella typhimurium and Escherichia coli, forward mutation in mouse lymphoma cells, and chromosome aberrations in Chinese hamster ovary cells) and in vivo (mouse micronucleus) assays.
In a fertility study in male rats, decreased number of pregnancies, decreased sperm concentration and motility, decreased reproductive organ weights, and testicular tubular degeneration were observed. These effects were observed at oral temsirolimus doses ≥3 mg/m2/day (approximately 0.2-fold the human recommended intravenous dose). Fertility was absent at 30 mg/m2/day.
In a fertility study in female rats, an increased incidence of pre- and post-implantation losses occurred at oral doses ≥4.2 mg/m2/day (approximately 0.3-fold the human recommended intravenous dose), resulting in decreased numbers of live fetuses.