Two-year carcinogenicity study in rats with a nonnucleoside reverse transcriptase inhibitor.

Area of Science:

• Toxicology
• Carcinogenesis
• Drug Safety Evaluation

Background:

• Lersivirine is a non-nucleotide reverse transcriptase inhibitor.
• Long-term toxicity studies are crucial for drug safety assessment.
• Understanding drug-induced neoplasms and their mechanisms is vital.

Purpose of the Study:

• To evaluate the long-term toxicity and carcinogenicity of lersivirine in Sprague-Dawley rats.
• To investigate the potential link between lersivirine administration and observed neoplastic lesions.
• To assess the human relevance of identified toxicological findings.

Main Methods:

• Daily oral gavage administration of lersivirine to Sprague-Dawley rats for up to 2 years.
• Monitoring of survival rates, body weights, and gross/histopathological examination of tissues.
• Analysis of lesion types, including neoplasms and proliferative changes in target organs.

Main Results:

• Lersivirine administration was associated with decreased survival and body weight.
• Increased incidence of neoplasms and proliferative lesions observed in the liver, thyroid, kidney, and urinary bladder.
• Lesions were consistent with hepatic microsomal enzyme induction, exacerbation of chronic progressive nephropathy, and urinary calculi/crystalluria.

Conclusions:

• Lersivirine induced significant toxicological effects, including neoplasms, in rats.
• Observed neoplasms were mechanistically linked to specific drug effects (enzyme induction, nephropathy, crystalluria).
• The identified neoplasms have low relevance for human risk assessment due to species-specific mechanisms.