Routine versus clinically driven laboratory monitoring of HIV antiretroviral therapy in Africa (DART): a randomised non-inferiority trial.

BACKGROUND: HIV antiretroviral therapy (ART) is often managed without routine laboratory monitoring in Africa; however, the effect of this approach is unknown. This trial investigated whether routine toxicity and efficacy monitoring of HIV-infected patients receiving ART had an important long-term effect on clinical outcomes in Africa. METHODS: In this open, non-inferiority trial in three centres in Uganda and one in Zimbabwe, 3321 symptomatic, ART-naive, HIV-infected adults with CD4 counts less than 200 cells per microL starting ART were randomly assigned to laboratory and clinical monitoring (LCM; n=1659) or clinically driven monitoring (CDM; n=1662) by a computer-generated list. Haematology, biochemistry, and CD4-cell counts were done every 12 weeks. In the LCM group, results were available to clinicians; in the CDM group, results (apart from CD4-cell count) could be requested if clinically indicated and grade 4 toxicities were available. Participants switched to second-line ART after new or recurrent WHO stage 4 events in both groups, or CD4 count less than 100 cells per microL (LCM only). Co-primary endpoints were new WHO stage 4 HIV events or death, and serious adverse events. Non-inferiority was defined as the upper 95% confidence limit for the hazard ratio (HR) for new WHO stage 4 events or death being no greater than 1.18. Analyses were by intention to treat. This study is registered, number ISRCTN13968779. FINDINGS: Two participants assigned to CDM and three to LCM were excluded from analyses. 5-year survival was 87% (95% CI 85-88) in the CDM group and 90% (88-91) in the LCM group, and 122 (7%) and 112 (7%) participants, respectively, were lost to follow-up over median 4.9 years' follow-up. 459 (28%) participants receiving CDM versus 356 (21%) LCM had a new WHO stage 4 event or died (6.94 [95% CI 6.33-7.60] vs 5.24 [4.72-5.81] per 100 person-years; absolute difference 1.70 per 100 person-years [0.87-2.54]; HR 1.31 [1.14-1.51]; p=0.0001). Differences in disease progression occurred from the third year on ART, whereas higher rates of switch to second-line treatment occurred in LCM from the second year. 283 (17%) participants receiving CDM versus 260 (16%) LCM had a new serious adverse event (HR 1.12 [0.94-1.32]; p=0.19), with anaemia the most common (76 vs 61 cases). INTERPRETATION: ART can be delivered safely without routine laboratory monitoring for toxic effects, but differences in disease progression suggest a role for monitoring of CD4-cell count from the second year of ART to guide the switch to second-line treatment. FUNDING: UK Medical Research Council, the UK Department for International Development, the Rockefeller Foundation, GlaxoSmithKline, Gilead Sciences, Boehringer-Ingelheim, and Abbott Laboratories.

Cytochrome P450 2B6 (CYP2B6) G516T influences nevirapine plasma concentrations in HIV-infected patients in Uganda.

OBJECTIVES: Polymorphisms in the cytochrome P450 (CYP) 2B6 gene have been shown to influence nevirapine plasma concentrations in HIV-infected European Caucasians. Although nevirapine is used extensively in Africa, the influence of CYP2B6 genotype on nevirapine exposure has not been assessed in this population. We aimed to determine the influence of CYP2B6 genotype at position 516 on nevirapine trough concentrations in HIV-infected patients in Kampala, Uganda. Additional polymorphisms in the CYP and multidrug resistance protein-1 (MDR-1) genes were also assessed for their impact on nevirapine concentrations. METHODS: The following genotypes were determined in all subjects using polymerase chain reaction-restriction fragment length polymorphism: CYP2B6 G516T, MDR-1 C3435T and G2677T, CYP3A4(*)1B and CYP3A5(*)3. Nevirapine plasma concentrations were determined using high-performance liquid chromatography in 23 HIV-infected patients who were generally healthy and had been taking nevirapine 200 mg twice daily for at least 14 days. Analysis of variance with post hoc testing was used to compare nevirapine concentrations among CYP2B6 genotype groups. RESULTS: The median nevirapine trough concentration in individuals homozygous for the variant allele (TT) was 7607 ng/mL vs 4181 and 5559 ng/mL for GG and GT individuals, respectively (GG vs TT median ratio=1.82; P=0.011). The mean ratio for TT vs GG individuals (95% confidence interval) was 1.51 (1.18, 1.84). No associations were observed between the other polymorphisms studied and nevirapine concentrations. CONCLUSIONS: CYP2B6 G516T significantly influenced nevirapine trough concentrations in HIV-infected patients in Uganda. Additional studies in larger patient populations are necessary to further define the potential clinical impact of these preliminary findings.