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U.S. Department of Health and Human Services

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Dose adjustments of PegIntron and Rebetol for certain patients with chronic hepatitis C

On May 8, 2009, FDA approved updates to the package insert for PegIntron (peginterferon alfa-2b), a polyethylene glycol-conjugated formulation of interferon alfa-2b, currently approved for the treatment of chronic hepatitis C (HCV) in patients 3 years of age and older with compensated liver disease, to reflect the results of the IDEAL study, P03471, which includes adding a two-step dose reduction scheme for PegIntron and increasing the dose of Rebetol to 1200 mg/day for patients who weigh between 81 and 85 kilograms.

The package insert for PegIntron has been revised to provide changes in the DOSAGE AND ADMINISTRATION section regarding the new two-step dose reduction for PegIntron in the event of poor tolerability or toxicity. Dose reduction recommendations include decreasing from PegInton 1.5 μg/kg/week to 1.0 μg/kg/week, then to 0.5 μg/kg/week if a second dose reduction is needed. In addition, dose recommendations for the accompanying dose of Rebetol in patients >80 to 85 kg have been revised to 1200 mg daily rather than 1000 mg daily. Study P03471 is described in the CLINICAL STUDIES section of the label.

The IDEAL study compared PegIntron 1.5 μg/kg/week and Pegintron 1.0 μg/kg/week both in combination with Rebetol and Pegasys 180 μg/week in combination with Copegus in 3070 treatment naive subjects with genotype 1 HCV infection. Overall, sustained viral response (SVR) rates were similar in all three treatment arms, however, the PegIntron 1.5 μg dose appeared to provide numerically higher sustained viral response (SVR) rates than the PegIntron 1.0 μg dose in many hard-to-treat subgroups including African Americans, patients > 40 years of age, and patients with high viral load. The two-step approach to dose reduction appears to provide optimal efficacy in the greatest number of patients while preserving demonstrated efficacy of PegIntron 1.0 μg/kg in those patients who require dose reduction because of intolerance or toxicity. A second dose reduction was required in a relatively small proportion of study subjects (2-7% across the arms).

Richard Klein
Office of Special Health Issues
Food and Drug Administration

Kimberly Struble
Division of Antiviral Drug Products
Food and Drug Administration