Low risk of treatment failure after substitution of nevirapine for protease inhibitors among human immunodeficiency virus infected patients with virus suppression

There is little information about the risk of treatment failure after a switch from human immunodeficiency virus (HIV) protease inhibitors (PIs) to nevirapine (Nvp) for patients with successful virus suppression. This study compared the 1-year risk of treatment failure for patients switching from a first PI-containing antiretroviral regimen to Nvp (Nvp group) with the risk for patients switching to second-line PIs (PI group) in the ATHENA (AIDS Therapy Evaluation, The Netherlands) study cohort (n = 2470) whose HIV-1 RNA loads were ≤ 500 copies/mL. Treatment failure was defined as measurement of HIV-1 RNA loads > 500 twice or > 10,000 copies/mL once or discontinuation of treatment for any reason. There were 446 eligible patients, 125 in the Nvp group and 321 in the PI group. The risk of treatment failure in the Nvp group, after data were adjusted for other risk factors, was 5-fold (95% confidence interval, 0.1-0.4) lower than the risk in the PI group, primarily because the discontinuation rate was lower. In patients with virus suppression, a switch to Nvp is more likely than a switch to second-line PIs to result in sustained virus suppression and maintenance of the new regimen.