Etravirine and rilpivirine resistance in HIV-1 subtype CRF01-AE-infected adults failing non-nucleoside reverse transcriptase inhibitor-based regimens

Abstract

Background: We studied prevalence of etravirine (ETR) and rilpivirine (RPV) resistance in HIV-1 subtype CRF01-AE infection with first-line non-nucleoside reverse transcriptase inhibitor (NNRTI) failure. Methods: A total of 225 adults failing two nucleoside reverse transcriptase inhibitors (NRTIs) plus 1 NNRTI in Thailand with HIV RNA > 1,000 copies/ml were included. Genotypic resistance results and HIV-1 subtype were interpreted by Stanford DR database. ETR resistance was calculated by the new Monogram weighted score (Monogram WS; ≥4 indicating high-level ETR resistance) and by DUET weighted score (DUET WS; 2.5-3.5 and ≥4 resulted in intermediate and reduce ETR response, respectively). RPV resistance interpretation was based on previous reports. Results: Median (IQR) age was 38 (34-42) years, 41% were female and CDC A:B:C were 22%:21%:57%. HIV subtypes were 96% CRF01-AE and 4% B. Antiretrovirals at failure were lamivudine (100%), stavudine (93%), nevirapine (90%) and efavirenz (10%) with a median (IQR) duration of 3.4 (1.8-4.5) years. Median (IQR) CD4 + T-cell count and HIV RNA were 194 (121-280) cells/mm 3 and 4.1 (3.6-4.6) log 10 copies/ml, respectively. The common NNRTI mutations were Y181C (41%), G190A (22%) and K103N (19%). The proportion of patients with Monogram WS score ≥4 was 61.3%. By DUET WS, 49.8% and 7.5% of patients were scored 2.5-3.5 and ≥4, respectively. Only HIV RNA≥4 log 10 copies/ml at failure was associated with both Monogram WS≥4 (OR 2.3, 95% CI 1.3-3.9; P=0.003) and DUET WS≥2.5 (OR 1.9, 95% CI 1.1-3.3; P=0.02). The RVP resistance-associated mutations (RAMs) detected were K101P (1.8%), Y181I (2.7%) and Y181V (3.6%). All patients with RPV mutation had ETR resistance. No E138R/E138K mutations were detected. Conclusions: Approximately 60% of patients had highlevel ETR resistance. The role of ETR in second-line therapy is limited in late NNRTI failure settings. RVP RAMs were uncommon, but cross-resistance between ETR and RVP was high. ©2011 International Medical Press.