A Single-dose Zoledronic Acid Infusion Prevents Antiretroviral Therapy-induced Bone Loss in Treatment-naive HIV-infected Patients: A Phase IIb Trial

Background: Human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) are associated with bone loss leading to increased fracture rate among HIV-infected individuals. ART-induced bone loss is most intense within the first 48 weeks of therapy, providing a window for prophylaxis with long-acting antiresorptives.

Methods: In a phase 2, double-blind, placebo-controlled trial, we randomized 63 nonosteoporotic, ART-naive adults with HIV initiating ART with atazanavir/ritonavir + tenofovir/emtricitabine to a single zoledronic acid (ZOL) infusion (5 mg) vs placebo to determine the efficacy of ZOL in mitigating ART-induced bone loss. Plasma bone turnover markers and bone mineral density (BMD) were performed at weeks 0, 12, 24, and 48 weeks. Primary outcome was change in C-terminal telopeptide of collagen at 24 weeks. Repeated-measures analyses using mixed linear models were used to estimate and compare study endpoints.

Results: The ZOL arm had a 65% reduction in bone resorption relative to the placebo arm at 24 weeks (0.117 ng/mL vs 0.338 ng/mL; P < .001). This effect of ZOL occurred as early as 12 weeks (73% reduction; P < .001) and persisted through week 48 (57% reduction; P < .001). The ZOL arm had an 8% higher lumbar spine BMD at 12 weeks relative to the placebo arm (P = .003), and remained 11% higher at 24 and 48 weeks. Similar trends were observed in the hip and femoral neck.

Conclusions: A single dose of ZOL administered at ART initiation prevented ART-induced bone loss through the first 48 weeks of ART, the period when ART-induced bone loss is most pronounced. Validation of these results in larger multicenter randomized clinical trials is warranted.

Clinical Trials Registration: NCT01228318.