Is zidovudine first‐line therapy virologically comparable to tenofovir in resource‐limited settings?

Objective To compare virologic success between adult patients on tenofovir ( TDF ) and zidovudine ( AZT )‐containing first‐line antiretroviral ( ART ) regimens in 10 rural clinics in Lesotho, Southern Africa. Methods Multicentre cross‐sectional study, patients ≥16 years, on first‐line ART ≥6 months, receiving AZT/lamivudine (3TC) or TDF/3TC combined with efavirenz (EFV) or nevirapine (NVP). Patient characteristics and clinical/therapeutic history were collected on the day of blood draw for viral load (VL). Analysis was stratified for non‐nucleoside reverse transcriptase inhibitor (EFV or NVP). A logistic regression model weighted for patients' baseline characteristics was used to assess the likelihood of virologic success (<80 copies/ml) in patients with TDF‐ as compared to AZT‐backbones. Results In total 1539 patients were included in the analysis. Most were clinically and immunologically stable (clinical failure: 2.7% ( AZT ) and 2.8% ( TDF ); immunological failure: 4.6% ( AZT ) and 4.8% ( TDF )). In EFV ‐based regimens ( n  = 1162), TDF was significantly associated with higher rates of virologic suppression than AZT (93.8% vs . 88.1%; weighted odds ratio: 2.15 (95% CI : 1.29–3.58; P  = 0.003)). In NVP ‐based regimens, a similar trend was observed, but not significant (89.4% vs . 86.7%; 1.99 (0.83–4.75, P  = 0.121)). Conclusion These findings support the WHO recommendation to use TDF /3 TC / EFV as first‐line regimen. They do, however, not support the recommendation that patients who are clinically stable on AZT should continue on this first‐line regimen.