Virologic and Immunologic Outcomes of Nevirapine- and Efavirenz-Based Tenofovir Disoproxil Fumarate-Containing Regimens When Use as a Switch Therapy

Background. Previous studies showed that tenofovir disoproxil fumarate/lamivudine/nevirapine (TDF/3TC/NVP) was the least efficacious of the 4 World Health Organization (WHO)-recommended TDF-containing regimens for an initial HIV therapy. We studied virologic and immunologic outcomes in HIV-infected persons who received TDF-containing regimens when used as a switch therapy. Methods. Observational cohort study was conducted in experienced adult HIV-infected persons who were treated with WHO-recommended TDF-containing regimens as a switch therapy at Ramathibodi hospital, Bangkok, Thailand, during 1 January 2007 to 29 February 2012. Virologic and immunologic outcomes were collected at initiation, at 24 and 48 weeks of the therapy. Results. During the study period, 240 patients were enrolled. Median (interquartile range [IQR]) age was 46 (41-52) years and 45% were female. Hepatitis B co-infection was found in 31 patients (12.92%). The median (IQR) CD4 counts at HIV diagnosis and at starting of the switch regimen were 88 (30-253) and 378 (251-518) cells/mm3, respectively. Among the studied regimens, no significantly difference in virologic and immunologic responses were observed between NVP-based (TDF/3TC/NVP and TDF/emtricitabine (FTC)/NVP) and EFV-based [TDF/3TC/efavirenz (EFV) and TDF/FTC/EFV] at 24 and 48 weeks. The proportion of patients with HIV RNA <50 copies/mL at 24 and 48 weeks were 91.7 and 78.9%, respectively for NVP-based regimen and 91.6 and 85.5%, respectively for EFV-based regimen (P value 0.969 and 0.181, respectively). CD4 counts at 24 and 48 weeks were 445 (312-610) and 460 (323-621) cells/mm3, respectively, for NVP-based regimen and 429 (281-552) and 434 (314-608) cells/mm3, respectively, for EFV-based regimen (P value 0.291 and 0.711, respectively). No significant difference of serum creatinine was observed at all time points. Conclusion. Virologic and immunologic responses were comparable between NVP- and EFV-based WHO-recommended TDF-containing regimens when used as a switch therapy. This suggests that NVP-based TDF-containing regimens can be used as a switch antiretroviral regimen without compromised efficacy. Disclosures. All authors: No reported disclosures.