Combined tipranavir and enfuvirtide use associated with higher plasma tipranavir concentrations but not with increased hepatotoxicity: sub-analysis from RESIST.

In RESIST, enfuvirtide co-administered with ritonavir-boosted tipranavir was associated with higher plasma tipranavir concentrations, which seldom rose above those associated with an increased risk of grade 3/4 transaminase elevations. Transaminase elevation rates (6.5%) and clinical hepatic event rates (5.9 events/100 person exposure years) were lower in the tipranavir/ritonavir with enfuvirtide group than in the tipranavir/ritonavir without enfuvirtide group. Observed increases in plasma tipranavir concentrations thus had no apparent effect on the risk of hepatotoxicity.