Abstract 1677: Epithelial Hyperplasia Induced by a Selective B-Raf Inhibitor, WYE-130600

The study evaluated the effects of WYE-130600, a selective B-Raf inhibitor, in preclinical trials on dogs and rats. In dogs, doses of 1 to 10 mg/kg led to dose-related dermal effects, including red discoloration, swelling, and desquamation, with microscopic changes such as epidermal and hair follicle hyperplasia. In rats, doses of 15 to 150 mg/kg caused similar skin effects, with epithelial hyperplasia and hyperkeratosis observed. At higher doses, rats also showed hair follicle atrophy and stomach inflammation. The findings indicated that epithelial hyperplasia was a common effect in both species, suggesting potential similar effects in humans.