PEG-Interleukin-2 Immunomodulation for HIV-1 Infected Individuals

Recombinant IL-2 (without PEG modification) was administered to HIV-infected patients by daily intradermal injection. At the low doses used, this was non-toxic, well-tolerated, and gave a systemic response as measured by natural killer cell and lymphokine-activated killer cell activity, but required daily administration. In the current study, the PEG modification of IL-2 is used since it has a much longer prolonged half-life compared with the non-PEG compound, without loss of functional activity. In the first, dose-escalation phase of the study, PEG-IL-2 is injected into the skin of the back by either the intradermal (ID) or subcutaneous (SC) route, to establish an optimal dose (which when given ID results in local induration = or > 25 mm without significant toxicity). The ID and SC routes are compared for systemic effect and toxicity. In the second phase of the study, the PEG-IL-2 is administered for 6-8 weeks using the optimal dosage, frequency, and route determined in the initial phase (probably 2-3 times per week) while local and systemic effects are monitored. These include measures of viral titer, peripheral blood mononuclear cell phenotype, CBC and CD4 counts, and in vitro cytotoxicity assays.