Comparison of changes in bone density and turnover with abacavir-lamivudine versus tenofovir-emtricitabine in HIV-infected adults: 48-week results from the ASSERT study.
Author(s): Stellbrink HJ, Orkin C, Arribas JR, Compston J, Gerstoft J, Van Wijngaerden E, Lazzarin A, Rizzardini G, Sprenger HG, Lambert J, Sture G, Leather D, Hughes S, Zucchi P, Pearce H, ASSERT Study Group
Affiliation(s): Infektions Medizinisches Centrum Hamburg Study Center, Hamburg, Germany.
Publication date & source: 2010-10-15, Clin Infect Dis., 51(8):963-72.
Publication type: Research Support, Non-U.S. Gov't
BACKGROUND: Abacavir-lamivudine and tenofovir DF-emtricitabine fixed-dose combinations are commonly used as first-line antiretroviral therapies. However, few studies have comprehensively compared their relative safety profiles. METHODS: In this European, multicenter, open-label, 96-week study, antiretroviral-naive adult subjects with human immunodeficiency virus (HIV) infection were randomized to receive either abacavir-lamivudine or tenofovir-emtricitabine with efavirenz. Primary analyses were conducted after 48 weeks of treatment. Bone mineral density (BMD), a powered secondary end point, was assessed by dual energy x-ray absorptiometry. Bone turnover markers (osteocalcin, procollagen 1 N-terminal propeptide, bone specific alkaline phosphatase, and type 1 collagen cross-linked C telopeptide [CTx]) were assessed in an exploratory analysis. RESULTS: A total of 385 subjects were enrolled in the study. BMD loss was observed in both treatment groups, with a significant difference in the change from baseline in both total hip (abacavir-lamivudine group, -1.9%; tenofovir-emtricitabine group, -3.6%; [Formula: see text]) and lumbar spine (abacavir-lamivudine group, -1.6%; tenofovir-emtricitabine group, -2.4%; P = .036). BMD loss of >or=6% was more common in the tenofovir-emtricitabine group (13% of the tenofovir-emtricitabine group vs 3% of the abacavir-lamivudine group had a loss of >or=6% in the hip; 15% vs 5% had a loss of >or=6% in the spine). Bone turnover markers increased in both treatment groups over the first 24 weeks, stabilizing or decreasing thereafter. Increases in all markers were significantly greater in the tenofovir-emtricitabine treatment group than in the abacavir-lamivudine group at week 24. All but CTx remained significantly different at week 48 (eg, osteocalcin: abacavir-lamivudine group, +8.07 mg/L; tenofovir-emtricitabine group, +11.92 mg/L; P < .001). CONCLUSIONS: This study demonstrated the impact of first-line treatment regimens on bone. Greater increases in bone turnover and decreases in BMD were observed in subjects treated with tenofovir-emtricitabine than were observed in subjects treated with abacavir-lamivudine.