A comprehensive hepatic safety analysis of nevirapine in different populations of HIV infected patients.

All classes of antiretroviral (ARV) therapy have been associated with asymptomatic elevations of alanine aminotransferase/aspartate aminotransferase (ALT/AST) levels, and much less frequently with serious, and at times life threatening, clinical liver hepatotoxicity. The relationship between the risk of developing serious clinical liver injury and the rate and severity of elevated asymptomatic ALT/AST levels is poorly understood. Boehringer Ingelheim has recently completed the Viramune Hepatic Safety Project; its primary objective was to identify risk factors for antiretroviral-associated hepatotoxicity. Data from 1731 nevirapine-treated patients and 1912 control patients who took part in Boehringer Ingelheim-controlled clinical trials as well as 814 nevirapine-treated patients in uncontrolled trials were analyzed. Risk factors for asymptomatic ALT/AST elevations during nevirapine therapy included baseline elevations of ALT/AST levels > 2.5x upper limit of normal (RR = 4.3, p < .01) and co-infection with hepatitis B (RR = 2.3, p < .01) or hepatitis C (RR = 5.2, p < .01). An analysis of ALT/AST elevations > 5x ULN for patients stratified by baseline CD4 cell count demonstrated that men with > or = 400 CD4 cells/mm3 were at increased risk of asymptomatic transaminase elevations while taking nevirapine (RR = 1.6, p < .01). No consistent CD4 cell count cutoff could be identified in women that was associated with an increased risk of ALT/AST elevations. Analyses from five large observational cohorts (N = 8711) demonstrated no significant differences in the rate of serious hepatic events among antiretroviral regimens, including between the non-nucleoside reverse transcriptase inhibitors nevirapine and efavirenz. Use of nevirapine was not associated with a significantly increased risk of clinical hepatotoxic events, including liver failure or liver related death, compared to therapy with other antiretroviral drugs.