Sequencing to NRTI plus NNRTI-only combinations after virological failure of protease inhibitor-based combination...

To examine the success of sequencing to nucleoside reverse transcriptase inhibitor (NRTI) plus nonnucleoside reverse transcriptase inhibitor (NNRTI)-only combinations after virological failure of protease inhibitor (PI)-based combinations in NNRTI-naïve individuals.

This was an observational cohort study.

171 patients were identified. The group was highly antiretroviral therapy-experienced with median cumulative NRTI and PI durations prior to change of 53 months and 21 months, respectively. The median CD4 count and viral load (VL) prior to change were 228 cells/mm(3) and 24500 copies/mL. Overall, 37.4% had a VL below the limit of detection (50 copies/mL) at 12 months (intention-to-treat analysis). Markers associated with success at 12 months were efavirenz (EFV) use, the use of three NRTI+NNRTI combinations, and abacavir (ABC) use. In multivariate analysis, use of EFV remained highly significant (relative hazard of virological success of nevirapine [NVP] vs. EFV = 0.39; p =.003), while ABC use became nonsignificant. A benefit from the use of three NRTI + NNRTI regimens was observed.

NRTI plus NNRTI-only combinations performed poorly, however the superior outcomes of patients treated with EFV are consistent with findings in cohort studies. The suggestion of benefit in patients receiving three NRTIs in addition to either NVP or EFV deserves further study in randomized trials.