Abstract
Background
This Phase IIb study explored the antiviral activity and safety of the investigational CCR5 antagonist aplaviroc (APL) in antiretroviral-naive patients harbouring R5-tropic virus.
Methods
One hundred and forty-seven patients were randomized 2:2:1 to one of two APL dosing regimens or efavirenz (EFV). All dosage arms were administered twice daily and in combination with lamivudine/zidovudine (3TC/ZDV; Combivir, COM). Efficacy, safety, and pharmacokinetic parameters were assessed.
Results
This study was prematurely terminated due to APL-associated idiosyncratic hepatotoxicity. The primary endpoint of the study was the proportion of patients with plasma HIV-1 RNA <400 copies/ml who remained on randomized treatment through week 12. Of the 147 patients enrolled, 145 patients received one dose of treatment and were included in the intention-to-treat population. The proportion of patients with HIV-1 RNA <400 copies/ml at week 12 was 53%, 50% and 66% in the APL 600 mg twice daily, APL 800 mg twice daily, and EFV arms, respectively. Common clinical adverse events (AEs) were diarrhoea, nausea, fatigue and headache. APL demonstrated non-linear pharmacokinetics with high interpatient variability. In addition to the hepatic findings, there was an apparent dose–response relationship in the incidence of diarrhoea.
Conclusions
Whereas target plasma concentrations of APL were achieved, the antiviral activity of APL as the third agent in a triple drug regimen did not appear to be comparable to EFV in this treatment-naive patient population.