FDA Approves Infergen Combo Therapy for Retreating HCV

Yael Waknine

July 12, 2010 — The US Food and Drug Administration (FDA) has approved an expanded indication for interferon alfacon-1 subcutaneous injection (Infergen; Three Rivers Pharmaceuticals, LLC), in combination with ribavirin, for retreatment of chronic hepatitis C (HCV) viral infection.

The action was based on data from the United States–based Daily-Dose Consensus Interferon and Ribavirin: Efficacy of Combined Therapy clinical trial of nonresponders to prior pegylated interferon plus ribavirin therapy who were randomly assigned to receive active treatment or placebo for up to 48 weeks.

Results showed that 9% of patients receiving 15 μg interferon alfacon-1/ribavirin achieved a sustained virologic response, defined as undetectable HCV RNA levels at 24 weeks posttherapy (vs placebo, 0%).

The retreatment strategy was especially effective for interferon-sensitive patients with lower baseline fibrosis scores. According to a company news release, up to 38% of noncirrhotic patients who were sensitive to pegylated interferon/ribavirin and who did not modify their interferon alfacon-1/ribavirin dosages achieved a sustained virologic response. Cirrhotic patients were less likely to benefit from treatment unless they displayed previous interferon sensitivity or a minimum 1 log10 drop in HCV RNA on prior therapy.

"Approximately 50 percent of patients with chronic hepatitis C do not respond to their initial course of therapy," stated Bruce Bacon, MD, in the company news release. "The FDA's recognition of this expanded label allows patients failing therapy a safe and efficacious retreatment strategy. The results from this study legitimize how we properly treat these patients helping them to achieve [a sustained virologic response]." Dr. Bacon was the lead investigator for the registration trial.

Adverse events most commonly reported with 15 μg interferon alfacon-1/ribavirin included fatigue, nausea, influenza-like symptoms, headache, arthralgia, myalgia, neutropenia, leukopenia, insomnia, and depression. Dose modifications were required in 52% of patients, primarily because of neutropenia/leukopenia, thrombocytopenia, and fatigue/weakness.

Interferon alfacon-1 previously was approved as monotherapy for chronic HCV in adults with compensated liver disease.

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Also See:
Consensus Interferon (Infergen) Label Changed to Include Data on Dosing with Ribavirin
Three Rivers Pharmaceuticals Announces FDA Approval Of Expanded Labeling of INFERGEN®