Minimum effective plasma concentration of efavirenz in treatment-naïve Chinese HIV-infected patients.

To assess the relationship between mean efavirenz (EFV) plasma concentration and clinical effect during the first 48 weeks of combination antiretroviral therapy (cART), the baseline CD4 cell count was recorded and plasma EFV concentration and CD4 cell count were measured every 12 weeks. HIV-RNA viral load was determined in the 48th week of cART. In total, 42 subjects were recruited and grouped according to their mean concentration of EFV during the study period: groups A, B and C with EFV concentrations (mean) <2 mg/L (1.8 mg/L), 2-4 mg/L (2.9 mg/L) and >4 mg/L (5.5 mg/L), respectively. The CD4 cell counts in group C increased more quickly than in groups B and A, although this was not statistically significant (211 ± 176/μL versus 151 ± 145/μL and 172 ± 105/μL, respectively; P = 0.799). Groups B and C had higher rates of HIV viral load suppression than group A (P = 0.017). For treatment-naïve Chinese HIV-infected patients, EFV plasma concentrations above 2 mg/L appear to suppress HIV replication more effectively than concentrations below 2 mg/L.