Safety of zidovudine dose reduction in treatment-naïve HIV infected patients. A randomized controlled study (MiniZID)

Background: Since September 2014, zidovudine (ZDV)-based therapy for HIV has been the preferred second-line WHO regimen in Cameroon, but its use is limited by the risk of anaemia at standard dosage. We assessed the safety of a reduced vs. standard dose of ZDV to decrease the risk of anaemia in treatment-naïve, HIV-infected individuals. Methods: In a prospective, randomized, open-label trial in an HIV clinic in Cameroon, 142 eligible adults (CD4 count < 350 cells/μL) were randomized to receive 24 weeks of a regimen comprising lamivudine plus nevirapine with either a reduced (400 mg) or standard dose (600 mg) of ZDV. The primary endpoint was the proportion of participants with new/worsening anaemia. Results: Median age was 35 years; 58.5% were women; median body mass index was 23.2 kg/m2. At baseline, median haemoglobin was 11.6 g/dL, median CD4 cell count was 163 cells/μL, and median plasma HIV-1 RNA load was 5.4 log10 copies/mL. The proportion of participants with new/worsening anaemia was 37.5% (400 mg ZDV) and 32.9% (600 mg ZDV) (P = 0.563). Ten patients with severe anaemia required a switch from ZDV to tenofovir (11.4% in standard-dose arm vs. 2.8% in low-dose arm; P = 0.054). At 24 weeks, there was no significant difference between treatment groups, including median CD4 T-cell count increases. Conclusions: No significant difference was observed in the overall rate of anaemia between HIV-infected individuals starting a ZDV-based treatment according to a standard- or reduced-dose regimen. Severe anaemia and treatment switches related to study drug, however, were more frequent with 600 mg than 400 mg ZDV.