Carcinogenicity assessment of lonidamine by dietary administration to Sprague-Dawley rats.

Following chronic dietary administration of 20, 60 and 180 mg/kg per day of lonidamine for 2 years to groups of Sprague-Dawley rats, treatment-related non-tumour findings seen microscopically included the following: atrophy of the testis with associated changes in epididymis and pituitary at all dosages; neuropathy in the sciatic nerve accompanied by skeletal muscle atrophy which was dose-related, particularly in male animals. Neither the incidence of tumour-bearing animals, nor the spectrum of tumours seen, was significantly changed. In the females given 180 mg/kg per day an overall reduction in tumour incidence was noted, which was reflected in a significant reduction (P < 0.001) in mammary tumours.