Virologic and immunologic activity of PegIntron in HIV disease

The primary objectives of this study were to evaluate the safety, tolerability, and antiviral activity of pegylated interferon-alpha (PegIntron) in HIV-1 treatment-experienced patients failing their current antiretroviral regimen.

This was a phase II, multicenter, randomized, double-blind, placebo-controlled study.

Patients were randomized to receive either weekly subcutaneous PegIntron 0.5, 1.0, 1.5, or 3 microg/kg or placebo added to their failing antiretroviral regimen for the first 4 weeks of study. Individuals who achieved more than 0.5 log10 reduction in HIV RNA at week 4 were allowed to continue study medication with optimization of their antiretroviral therapy for an additional 24 weeks.

In the 259 patients included in the intent-to-treat analysis, changes in plasma HIV RNA from baseline to week 4 were -0.25 (P > 0.5), -0.46 (P = 0.024), -0.39 (P = 0.008), -0.53 (P < 0.001), and -0.17 (P > 0.5) log10 copies/ml in the 0.5, 1.0, 1.5, and 3.0 microg/kg and placebo arms, respectively. No significant changes were seen in CD4 T-cell parameters in any of the treatment or control arms. Adverse events (most commonly fever, flu-like symptoms, other constitutional symptoms, and psychiatric symptoms) resulted in discontinuation of study medication in 13, 17, 16, 28, and 2% of patients in the 0.5, 1.0, 1.5, 3.0 microg/kg, and placebo group, respectively.

The demonstration of significant antiviral activity in a heavily pretreated patient population with acceptable toxicity and only weekly dosing makes PegIntron a potentially valuable therapy for patients with HIV infection that warrants further investigation in a broader population of patients.