Long-term Efficacy and Safety of Tenofovir Disoproxil Fumarate in HIV-1-infected Adolescents Failing Antiretroviral Therapy: The Final Results of Study GS-US-104–0321

BACKGROUND:Reports of long-term tenofovir disoproxil fumarate (TDF) treatment in HIV-infected adolescents are limited. We present final results from the open-label (OL) TDF extension following the randomized, placebo (PBO)-controlled, double-blind phase of GS-US-104-0321 (Study 321). METHODS:HIV-infected 12- to 17-year-olds treated with TDF 300 mg or PBO with an optimized background regimen (OBR) for 24–48 weeks subsequently received OL TDF plus OBR in a single arm study extension. HIV-1 RNA and safety, including bone mineral density (BMD), was assessed in all TDF recipients. RESULTS:Eighty-one subjects received TDF (median duration 96 weeks). No subject died or discontinued OL TDF for safety/tolerability. At week 144, proportions with HIV-1 RNA 1000 c/mL initially randomized to TDF), 41.7% (5 of 12 subjects with HIV-1 RNA 1000 c/mL and switched PBO to TDF). Viral resistance to TDF occurred in 1 subject. At week 144, median decrease in estimated glomerular filtration rate was 38.1 mL/min/1.73 m (n = 25). Increases in median spine (+12.70%, n = 26) and total body less head BMD (+4.32%, n = 26) and height-age adjusted Z-scores (n = 21; +0.457 for spine, +0.152 for total body less head) were observed at week 144. Five of 81 subjects (6%) had persistent >4% BMD decreases from baseline. CONCLUSIONS:Some subjects had virologic responses to TDF plus OBR, and TDF resistance was rare. TDF was well tolerated and can be considered for treatment of HIV-infected adolescents.