Discontinuation of nevirapine because of hypersensitivity reactions in patients with prior treatment experience, compared with treatment-naive patients: the ATHENA cohort study.

BACKGROUND Recommendations that nevirapine (NVP) should be avoided in female individuals with CD4 cell counts >250 cells/microL and in male individuals with CD4 cell counts >400 cells/microL are based on findings in treatment-naive patients. It is unclear whether these guidelines also apply to treatment-experienced patients switching to NVP-based combination therapy. METHODS Patients in the ATHENA cohort study who had used NVP-based combination therapy were included. We identified patients who discontinued NVP-based combination therapy because of hypersensitivity reactions (HSRs; rash and/or hepatotoxicity) within 18 weeks after starting such therapy. We grouped patients according to their CD4 cell count at the start of NVP-based combination therapy (current CD4 cell count) as having a high CD4 cell count (for female patients, >250 cells/microL; for male patients, >400 cells/microL) or a low CD4 cell count. Treatment-experienced patients were further subdivided according to the last available CD4 cell count before first receipt of antiretroviral therapy (ART; pre-ART CD4 cell count) using the same criteria. Risk factors for HSR were assessed using multivariate logistic regression. RESULTS Of 3752 patients receiving NVP-based combination therapy, 231 patients (6.2%) discontinued NVP therapy because of HSRs. Independent risk factors included female sex and Asian ethnicity. Having an undetectable viral load (VL) at the start of NVP therapy was associated with reduced risk of developing an HSR (adjusted odds ratio [OR], 0.52; 95% confidence interval [CI], 0.38-0.71). Pretreated patients with low pre-ART and high current CD4 cell counts and a detectable VL when switching to NVP-based combination therapy had a significantly higher risk of developing an HSR, compared with treatment-naive patients who started NVP therapy with low CD4 cell counts (adjusted OR, 1.87; 95% CI, 1.11-3.12); pretreated patients with low pre-ART CD4 cell counts who switched to NVP therapy with a high current CD4 cell count and an undetectable VL did not have an increased risk of developing an HSR (adjusted OR, 1.03; 95% CI, 0.66-1.61). CONCLUSIONS Treatment-experienced patients who start NVP-based combination therapy with low pre-ART and high current CD4 cell counts and an undetectable VL have a similar likelihood for discontinuing NVP therapy because of HSRs, compared with treatment-naive patients with low CD4 cell counts. This suggests that NVP-based combination therapy may be safely initiated in such patients. However, in similar patients with a detectable VL, it is prudent to continue to adhere to current CD4 cell count thresholds.