By Liz Highleyman

Bone loss (osteopenia and the more severe form, osteoporosis) is a potential metabolic complication in people with HIV; some studies suggest it may be associated with antiretroviral therapy.

Normally bone is created and re-absorbed in a dynamic process. The bisphosphonate drug alendronate (Fosamax), which slows the re-absorption of bone by cells called osteoclasts, is approved for the treatment of osteoporosis in HIV negative people.

As reported at the 14th Conference on Retroviruses and Opportunistic Infections last week in Los Angeles, Grace McComsey and colleagues conducted a study (ACTG 5163) evaluating the effect of alendronate on bone mineral density (BMD) in 82 HIV positive patients with documented bone loss.

The mean age was 48 years, about 30% were women, about 77% were white, 35% smoked, and the median body mass index (BMI) was about 24.0. Most subjects had well-controlled HIV disease, with undetectable viral load (90% < 400 copies/mL) and a median CD4 cell count of about 500 cells/mm3. A majority (65%) were taking protease inhibitors and 38% were taking tenofovir (Viread).

Participants received either 70 mg once-weekly oral alendronate plus calcium and vitamin D supplements, or else the 2 supplements alone for 48 weeks. Bone density was evaluated using DEXA scans.

Results

• At week 48, the alendronate arm had significantly greater increases in BMD compared with the supplements-only arm:

- lumbar spine: 3.38% vs 1.10%;
- hip: 3.95% vs 1.31%;
- trochanter (upper part of the thigh bone): 4.52% vs 0.72%.

• A slightly greater increase in BMD of the femoral neck did not reach statistical significance (2.21% vs 1.24%).

• The sex of participants did not affect response to therapy.

• Black participants receiving alendronate experienced smaller increases in lumbar spine BMD compared with whites.

• Results did not change when 5 patients who added or stopped tenofovir during the study were excluded from the analysis.

• Alendronate was well-tolerated overall.

• There were no differences in the frequency of grade 2 or higher laboratory abnormalities in the 2 arms.

• No participants in either arm discontinued therapy due to drug-related toxicity.

Conclusion

The investigators concluded that, "The results demonstrate that once-weekly alendronate is safe and efficacious in the treatment of decreased bone mineral density in HIV-infected patients. Vitamin D and calcium alone is associated with modest improvements in bone mineral density."

Case Western Reserve University, Cleveland, OH; Statistical & Data Analysis Ctr, Harvard School of Public Health, Boston, MA; University of Pennsylvania, Philadelphia, PA; University of Nebraska Medical Ctr, Omaha, NE; Social & Sci Systems, Silver Spring, MD; NIAID, NIH, Bethesda, MD; Frontier Sci & Tech Research Fndn, Amherst, NY; Brown Medical School, Providence, RI; University of California, San Diego, CA; University of North Carolina at Chapel Hill, NC.

Link to study abstract.

03/06/07

Reference
G A McComsey, M Kendall, P Tebas, and others. Alendronate with Calcium and Vitamin D Supplementation Is Superior to Calcium and Vitamin D Alone in the Management of Decreased Bone Mineral Density in HIV-infected patients: Results of ACTG 5163. 14th Conference on Retroviruses and Opportunistic Infections. Los Angeles. February 25-28, 2007. Abstract 42 (oral).