Safety and Efficacy of Switching From Stavudine or Zidovudine to Tenofovir DF in HIV-1 Infected Children

A Phase III, Randomized, Open-Label Study Comparing the Safety and Efficacy of Switching Stavudine or Zidovudine to Tenofovir Disoproxil Fumarate Versus Continuing Stavudine or Zidovudine in Virologically Suppressed HIV-Infected Children Taking Highly Active Antiretroviral Therapy

The primary objective of this study is to assess the efficacy of switching to tenofovir disoproxil fumarate (TDF) compared to continuing stavudine or zidovudine in maintaining virologic suppression in HIV-1 infected children.

Major Inclusion Criteria:

• Documented laboratory diagnosis of HIV-1 infection
• Plasma HIV-1 RNA < 400 copies/mL
• Currently on a stable stavudine or zidovudine -containing antiretroviral therapy regimen for at least 12 weeks
• Naive to tenofovir DF

Key Inclusion Criteria for the First 96-Week Extension

• Completed 48 weeks of treatment in Arm 1 or Arm 2 of the study
• <18 years of age (at the start of the extension)
• Participants initially randomized to Arm 2 will be given the option to replace stavudine or zidovudine with tenofovir DF in the 96-week extension at the investigator's discretion, if the investigator determines that tenofovir DF is safe and beneficial for the participant.

Key Inclusion Criteria for the Second and Third 96-Week Extension and Fourth Open-Ended Extension

• Completed of treatment with study drug in the first extension phase
• <18 years of age at the start of the extension. This inclusion criterion is not applicable in those regions where tenofovir DF is not commercially available for treatment of HIV-1 infection in adults.

Key Exclusion Criteria:

• Participants receiving ongoing therapy with any of the following
• Nephrotoxic agents
• Systemic chemotherapeutic agents
• Systemic corticosteroids
• Interleukin 2 (IL 2) and other immunomodulating agents
• Investigational agents
• Pregnant or lactating participants
• Evidence of a gastrointestinal malabsorption syndrome or chronic nausea or vomiting which may confer an inability to receive an orally administered medication
• Current alcohol or substance abuse judged by the investigator to potentially interfere with participant compliance
• Malignancy other than cutaneous Kaposi's sarcoma (KS) or basal cell carcinoma.
• Active, serious infections (other than HIV-1 infection) requiring parenteral antibiotic therapy within 15 days prior to screening
• Prior history of significant renal disease (ie, nephrotic syndrome, renal dysgenesis, polycystic kidney disease, congenital nephrosis)
• Prior history of significant bone disease (ie, osteomalacia, chronic osteomyelitis, osteogenesis imperfecta, osteochondroses, multiple bone fractures)

Note: Other protocol defined Inclusion/ Exclusion criteria may apply.