Safety and Efficacy of Tenofovir DF in HIV-1 Infected Adolescents Failing Their Current Antiretroviral Therapy

This is a 48-week, randomized, double-blind, placebo-controlled, multicenter study of the safety and efficacy of tenofovir DF as part of an optimized antiretroviral regimen in HIV-1 infected adolescents (12 years to < 18 years of age) who are failing their current antiretroviral regimen and have HIV-1 RNA levels ≥ 1000 copies/mL at screening. Data from three consecutive 96-week study extensions have been used to evaluate the long-term efficacy, safety, and tolerability of open-label tenofovir DF as part of an antiviral regimen, providing data for up to 336 weeks of total drug exposure.

Pretreatment:

HIV-1 genotyping will be performed as part of the screening assessments to assist in the construction of an OBR, defined as at least 3, but no more than 5 antiretroviral agents, not including tenofovir DF or placebo.

Randomized Phase:

Participants will be randomized in a 1:1 ratio to receive either tenofovir DF + OBR, or placebo + OBR. The majority of efficacy and safety assessments will be performed at each clinic visit (Weeks 4, 8, 16, 24, 32, 40, and 48). At Week 24, participants who are adherent to study drug (in the opinion of the investigator), but do not demonstrate a ≥ 0.5 log10 copies/mL decrease from baseline in HIV-1 RNA, will be considered to be nonresponders and will be unblinded. Nonresponders randomized to the placebo group will be given the option to continue on study and receive open-label tenofovir DF with an appropriate background regimen determined by the investigator. Nonresponders randomized to the tenofovir DF treatment group will be discontinued from the study.

Extension Phases:

After completing 48 weeks of double-blind treatment with tenofovir DF or placebo, participants who have not reached 18 years of age, and who, in the opinion of the investigator, would derive clinical benefit from the use of open-label tenofovir DF, will be given the option to continue (or initiate) treatment with open-label tenofovir DF in the first of three 96 week study extension periods. Nonresponders who receive open-label tenofovir DF after Week 24 will also be considered eligible for the first study extension if they met the above criteria at Week 48.

After completing the first 96 week study extension, participants who have not reached 18 years of age, and who have shown ongoing clinical benefit from tenofovir DF, will be given the option to continue receiving open-label tenofovir DF for an additional 96 weeks or until tenofovir DF became commercially available in the country where the participants are enrolled, whichever occurs first.

After completing the second 96 week study extension, participants who have not reached 18 years of age, and who have shown ongoing clinical benefit from tenofovir DF, will be given the option to continue receiving open-label tenofovir DF for an additional 96 weeks or until tenofovir DF became commercially available in the country where the participants are enrolled, whichever occurs first.

Presentation of data:

After the randomized phase of the study, participants randomized to placebo during the randomized phase of the study and then switch to open-label tenofovir DF will have their baseline reset (defined as open-label baseline), and only outcome data collected after (on/after for adverse events (AEs)/concomitant medications) participants receive their first dose of open-label tenofovir DF will be included.

Major Inclusion Criteria:

• Weight ≥ 35 kg
• Documented laboratory diagnosis of HIV infection
• Plasma HIV-1 RNA ≥ 1000 copies/mL
• Prior antiretroviral treatment experience with at least 2 antiretroviral drug classes
• Naive to tenofovir DF
• Absence of K65R mutation on genotypic testing

Exclusion criteria

• Patients requiring didanosine in background regimen
• Prior history of significant renal disease
• Prior history of significant bone disease