An international team compared the clinical effects of peginterferon alpha-2a with those of interferon alpha-2a in the initial treatment of patients with chronic hepatitis C.
Peginterferon alpha-2a is a covalently modified version of interferon alpha-2a, with a 40-kd branched-chain polyethylene glycol moiety attached. The result is a compound that has sustained absorption, a slower rate of clearance, and a longer half-life than unmodified interferon alpha-2a.
531 chronic hepatitis C patients were randomly assigned to receive either 180 µg of peginterferon alpha-2a once per week, for 48 weeks (267 patients), or 6 million units of interferon alpha-2a, three times per week for 12 weeks, followed by 3 million units three times per week for 36 weeks (264 patients).
Patients were assessed at week 72 for a sustained virologic response, defined as an undetectable level of hepatitis C virus RNA (<100 copies per milliliter).
The team found that peginterferon alpha-2a was associated with a higher rate of virologic response than was interferon alpha-2a at week 48 (69 per cent vs. 28 per cent) and at week 72 (39 per cent vs. 19 per cent).
Undetectable Hepatitis C with peginterferon and interferon, respectively:
Week 48 69% vs. 28%
Week 72 45% vs. 25%
Sustained normalization of serum alanine aminotransferase concentrations at week 72 was also more common in the peginterferon group (45 per cent vs. 25 per cent).
The two groups were similar with respect to the frequency and severity of adverse events, which were typical of those associated with interferon alpha.
Dr Stefan Zeuzem concluded on behalf of the group that, "In patients with chronic hepatitis C, a regimen of peginterferon alfa-2a given once weekly is more effective than a regimen of interferon alfa-2a given three times weekly."