Safety and Effectiveness of Alendronate for Bone Mineral Density in HIV-infected Children and Adolescents

Puberty is a time when the foundation is laid for healthy bone mass. Over the course of puberty, 26% of bone mass is established in the 4-year period of peak height velocity and up to 60% of adult peak bone mass is established. Factors that affect normal bone mineralization include calcium intake, vitamin D status, degree of physical and weight bearing activities, hormones, genetics, body weight, and general health and nutrition status. HIV-infected children, youth, and adults have lower bone mineral density (BMD) than would be expected for healthy people of similar age, weight, and race. As the majority of perinatally HIV-infected U.S. children are entering or in adolescence, the potential for HIV-related impaired BMD during the adolescent peak of bone mass acquisition is of particular concern. The purpose of this study was to compare changes in BMD of the lumbar spine from pre-treatment levels to 24 and 48 weeks after alendronate treatment or placebo in HIV-infected children and adolescents.

Participants were randomized equally into one of three groups: Group 1A received alendronate for 96 weeks; Group 1B received alendronate for 48 weeks followed by placebo for 48 weeks; Group 2 received placebo for 48 weeks followed by alendronate for 48 weeks. All three groups were followed off treatment for an additional 48 weeks. Participants also received vitamin D/calcium for the duration of the study and were asked to perform 60 minutes of weight-bearing exercise each day.

Clinic visits were scheduled every 12 weeks after entry, with telephone contact visits one, four, and 28 weeks after entry and the week 48 visit. A physical exam and dental assessment was conducted at each clinic visit, and a history of adverse events collected. Dual Energy X-ray absorptiometry (DXA), hematology and chemistry panels were conducted at entry and weeks 24, 48, 72, 96 and 144. Lumbar spine and whole body (with head) BMD was measured using Hologic DXA scanners (QDR4500A, QDR4500W or Delphi A models).

The primary analysis compared changes from entry to 24 and 48 weeks in lumbar spine BMD between Groups 1A and 1B combined (both on alendronate for initial 48 weeks) vs. Group 2 (on placebo for 48 weeks). Study participants were unblinded after 96 weeks of follow-up (the primary completion date) but remained on study, off study treatment, for an additional 48 weeks.

Secondary laboratory outcomes listed in the protocol (bone marker turnover and Receptor Activator of Nuclear Factor Kappa-B Ligand/Osteoprotegerin (RANKL/OPG) Ratio) and central fat content, which required application for additional funding for laboratory testing, will not be performed and no results will be available.

Inclusion criteria

(Version 2.0 of protocol):

• Documentation of HIV-1 infection
• HIV-infection acquired before puberty
• For participants receiving antiretroviral therapy, must have been on the same antiretroviral agents for at least 12 weeks prior to study entry and have a viral load less than 10,000 copies/mL. For participants not receiving antiretroviral therapy, must have not been on antiretroviral agents for at least 12 weeks prior to study entry and have no indication for therapy
• Lumbar spine DXA BMD z-score less than -1.5 or history of fragility fracture within the prior 12 months (regardless of DXA result).
• Available for routine dental exam and care every 6 months
• Demonstrated ability and willingness to swallow study medications
• Females of reproductive potential must have had a negative pregnancy test at screening and within 48 hours prior to study entry. They must also have agreed to avoid pregnancy while on the study and if engaging in sexual activity, use at least two forms of contraception.
• Parent or legal guardian able and willing to provide signed informed consent for children who could not provide consent for themselves.

Exclusion criteria

(Version 2.0 of protocol):

• Body weight more than 300 lbs.
• For female participants: if on Depo-Provera, they must have been on it for at least 1 year prior to study entry; if not on Depa-Provera, they must have not been on it for at least 1 year prior to study entry.
• Anticonvulsant therapy
• Proven growth hormone deficiency
• Use of growth hormone in the 12 months prior to entry
• Primary hyperparathyroidism
• Hypoparathyroidism
• Renal failure
• Cushing syndrome
• Active dental infection
• Dental or periodontal disease expected to require more than basic restorative care
• Pregnancy or lactation
• Esophageal or gastric ulcer, chronic nonsteroidal anti-inflammatory drug (NSAID) use, or aspirin use
• Tenofovir disoproxil fumarate (TDF): if on TDF, they must have been on it for at least 6 months prior to study entry; if not on TDF, they must have not been on it for at least 6 months prior to study entry.
• Hemoglobin less than 10 g/dL
• Any past pharmacologic treatment (except vitamin D and/or calcium supplementation) for low bone density
• Inability to stand or sit upright for at least 30 minutes
• Hypersensitivity to any component of alendronate
• Hypocalcemia (less than the lower limit of normal established by the local laboratory in which it was performed)
• Known abnormalities of the esophagus that delay esophageal emptying such as stricture or achalasia
• 25-OH vitamin D less than 10 ng/mL in combination with elevated intact PTH above the upper limit of normal for the local laboratory in which it was performed