Early versus delayed fixed dose combination abacavir/lamivudine/zidovudine in patients with HIV and tuberculosis in Tanzania

Abstract

Fixed dose combination abacavir/lamivudine/zidovudine (ABC/3TC/ZDV) among HIV-1 and tuberculosis (TB)-coinfected patients was evaluated and outcomes between early vs. delayed initiation were compared. In a randomized, pilot study conducted in the Kilimanjaro Region of Tanzania, HIV-infected inpatients with smear-positive TB and total lymphocyte count <1200/mm(3) were randomized to initiate ABC/3TC/ZDV either 2 (early) or 8 (delayed) weeks after commencing antituberculosis therapy and were followed for 104 weeks. Of 94 patients screened, 70 enrolled (41% female, median CD4 count 103 cells/mm(3)), and 33 in each group completed 104 weeks. Two deaths and 12 serious adverse events (SAEs) were observed in the early arm vs. one death, one clinical failure, and seven SAEs in the delayed arm (p = 0.6012 for time to first grade 3/4 event, SAE, or death). CD4 cell increases were +331 and +328 cells/mm(3), respectively. TB-immune reconstitution inflammatory syndromes (TB-IRIS) were not observed in any subject. Using intent-to-treat (ITT), missing = failure analyses, 74% (26/35) vs. 89% (31/35) randomized to early vs. delayed therapy had HIV RNA levels <400 copies/ml at 104 weeks (p = 0.2182) and 66% (23/35) vs. 74% (26/35), respectively, had HIV RNA levels <50 copies/ml (p = 0.6026). In an analysis in which switches from ABC/3TC/ZDV = failure, those receiving early therapy were less likely to be suppressed to <400 copies/ml [60% (21/35) vs. 86% (30/35), p = 0.030]. TB-IRIS was not observed among the 70 coinfected subjects beginning antiretroviral treatment. ABC/3TC/ZDV was well tolerated and resulted in steady immunologic improvement. Rates of virologic suppression were similar between early and delayed treatment strategies with triple nucleoside regimens when substitutions were allowed.

FIG. 1.

Tuberculosis and HIV Immune Reconstitution Syndrome Trial (THIRST) profile and disposition of study subjects, postrandomization. *ART, antiretroviral therapy; ^†ABC/LMV/ZDV, fixed dose combination of abacavir, lamivudine, and zidovudine; ^‡ABC/LMV/d4T, fixed dose combination of abacavir, lamivudine, and stavudine; ^¶TDF/LMV/ZDV, fixed dose combination of tenofovir, lamivudine, and zidovudine.

FIG. 2.

Median CD4 cell counts with interquartile ranges among THIRST subjects randomized to receive early vs. delayed antiretroviral therapy in relation to initiation of antituberculosis therapy, beginning at ART initiation through 104 weeks.

FIG. 3.

Proportion of THIRST participants with plasma HIV RNA levels <400 copies/ml and <50 copies/ml at 104 weeks of ART.