Efficacy and Safety of Adefovir Dipivoxil With Antiretroviral Therapy
A Randomized Controlled Trial
- James Kahn, MD;
- Stephen Lagakos, PhD;
- Michael Wulfsohn, MD, PhD;
- Deborah Cherng, MS;
- Michael Miller, PhD;
- Julie Cherrington, PhD;
- David Hardy, MD;
- Gildon Beall, MD;
- Richard Cooper, MD;
- Robert Murphy, MD;
- Nesli Basgoz, MD;
- Edmund Ng, PhD;
- Steven Deeks, MD;
- Dean Winslow, MD;
- John J. Toole, MD, PhD;
- Dion Coakley, PharmD;
- for the GS-408 Study Team
- Author Affiliations: Positive Health Program University of California San Francisco, San Francisco General Hospital, San Francisco (Drs Kahn and Deeks); Gilead Sciences Inc, Foster City (Drs Wulfsohn, Miller, Cherrington, Winslow, Toole, and Coakley); Pacific Oak Research, Beverly Hills (Dr Hardy); Harbor University of California Los Angeles Medical Center, Torrance (Dr Beall); Kraus Medical Partners, Los Angeles (Dr Cooper), Calif; School of Public Health, Harvard University (Drs Lagakos and Ng and Ms Cherng), and Massachusetts General Hospital (Dr Basgoz), Boston, Mass; and Northwestern University Medical School, Chicago, Ill (Dr Murphy).
Abstract
Context Adefovir dipivoxil is a nucleotide analog that has demonstrated effective antiretroviral activity against human immunodeficiency virus (HIV) with once-daily administration.
Objective To determine if adefovir confers antiretroviral or immunologic benefit when added to stable antiretroviral therapy.
Design Multicenter, 24-week, randomized, double-blind, placebo-controlled study. Enrollment was conducted from June 3, 1996, through May 6, 1997.
Setting Thirty-three US HIV treatment centers.
Participants Of 1171 patients screened, 442 patients infected with HIV receiving stable antiretroviral therapy for at least 8 weeks with plasma HIV RNA greater than 2500 copies/mL and CD4+ cell count above 0.20 × 109/L were randomized.
Intervention Patients were randomized to receive either a single 120-mg/d dose of adefovir dipivoxil (n = 219) or an indistinguishable placebo (n = 223). All patients received L-carnitine, 500 mg/d. Open-label adefovir was offered after 24 weeks and was continued until the end of the study.
Main Outcome Measures Changes in HIV RNA from baseline, based on area under the curve and CD4+ cell levels, adverse events, and effect of baseline genotypic resistance on response to adefovir.
Results Patients assigned to adefovir demonstrated a 0.4-log10 decline from baseline in HIV RNA compared with no change in the placebo group (P<.001), which continued through 48 weeks. CD4+ cell counts did not change. During the initial 24 weeks, elevated hepatic enzyme levels (P<.001), gastrointestinal tract complaints (P<.001), and weight loss (P<.001) were associated with use of adefovir. Between 24 weeks and 48 weeks elevations in serum creatinine occurred in 60% of patients, usually returning to baseline after discontinuation of adefovir. Patients with lamivudine or lamivudine and zidovudine resistance mutations demonstrated anti–HIV effects with adefovir (P≤.01 vs placebo group).
Conclusions This study suggests that once-daily adefovir therapy reduces HIV RNA and is active against isolates resistant to lamivudine or lamivudine and zidovudine. Nephrotoxicity occurred when treatment extended beyond 24 weeks but was reversible.
