A multicenter study of recombinant human interleukin 12 for the treatment of chronic hepatitis C virus infection in patients nonresponsive to previous therapy.

Recombinant human interleukin 12 (IL-12) is an immunomodulatory cytokine that is active against several viruses. Treatment options in patients with chronic hepatitis C with nonresponse to interferon (IFN)-based therapy are limited. Prior dose-ranging studies have indicated drug tolerability and transient suppression of hepatitis C virus (HCV) RNA by IL-12. The aim of this study was to determine the safety and efficacy of prolonged IL-12 therapy in patients who have failed treatment with IFN-alpha +/- ribavirin. A total of 225 patients at 21 U.S. sites who had a history of nonresponse to IFN-alpha or combination IFN-alpha plus ribavirin for treatment of HCV were randomized to 500 ng/kg IL-12 or placebo subcutaneously twice weekly for 12 weeks. The groups were then unblinded; patients receiving IL-12 continued for another 36 weeks, and the placebo group received 48 weeks of treatment with IL-12 in an open-label fashion. HCV RNA, serum alanine aminotransferase (ALT) level, and a repeat liver biopsy were assessed at 24 weeks following therapy. Approximately 1% (2 of 160) of nonresponsive patients enrolled for treatment had a sustained virologic response to IL-12 therapy, but 3% (7 of 225) developed severe adverse events probably related to treatment, resulting in early termination of the trial. Common adverse effects reported by most patients included chills, fever, fatigue, headache, and arthralgia. At termination of the study, 160 patients had received at least 8 weeks of treatment with IL-12. Paired liver biopsy specimens were available for evaluation in 54 patients, but there were no significant changes in Knodell fibrosis or histologic activity index (HAI) scores. In conclusion, IL-12 as monotherapy at the doses used in this trial for chronic hepatitis C has low efficacy, was poorly tolerated, and is unlikely to provide an alternative to conventional IFN-based therapy.

Daptomycin pharmacokinetics and safety following administration of escalating doses once daily to healthy subjects.

The purpose of this paper is to establish the pharmacokinetics and safety of escalating, once-daily doses of daptomycin, a novel lipopeptide antibiotic active against gram-positive pathogens, including those resistant to methicillin and vancomycin. This phase 1, multiple-dose, double-blind study involved 24 healthy subjects in three dose cohorts (4, 6, and 8 mg/kg of body weight) who were randomized to receive daptomycin or the control at a 3:1 ratio and administered the study medication by a 30-min intravenous infusion every 24 h for 7 to 14 days. Daptomycin pharmacokinetics was assessed by blood and urine sampling. Safety and tolerability were evaluated by monitoring adverse events (AEs) and laboratory parameters. Daptomycin pharmacokinetics was linear through 6 mg/kg, with a slight ( approximately 20%) nonlinearity in the area under the curve and trough concentration at the highest dose studied (8 mg/kg). The pharmacokinetic parameters measured on the median day of the study period, (day 7) were half-life ( approximately 9 h), volume of distribution ( approximately 0.1 liters/kg), systemic clearance ( approximately 8.2 ml/h/kg), and percentage of the drug excreted intact in urine from 0 to 24 h ( approximately 54%). Daptomycin protein binding (mean amount bound, 91.7%) was independent of the drug concentration. No gender effect was observed. All subjects who received daptomycin completed the study. The frequencies and distributions of treatment-emergent AEs were similar for the subjects who received daptomycin and the control subjects. There were no serious AEs and no pattern of dose-related events. The pharmacokinetics of once-daily administration of daptomycin was linear through 6 mg/kg. For all three doses, plasma daptomycin concentrations were consistent and predictable throughout the dosing interval. Daptomycin was well tolerated when it was administered once daily at a dose as high as 8 mg/kg for 14 days.