Comparative study of pegylated interferon formulations in HCV monotherapy

Tracy Swan, TAG

On 14 January, Schering Plough company issued a press release announcing top-line results of an HCV treatment trial for people with HCV monoinfection (the IDEAL Study), that compared efficacy of three different regimens of pegylated interferon based treatment. [1]

  • Schering’s PEG-INTRON (peginterferon alfa-2b) at the FDA approved dose, 1.5 micrograms per kilogram,
  • A lower dose of PEG-INTRON (peginterferon alfa-2b) of 1.0 micrograms per kilogram,
  • Roche’s fixed-dose PEGASYS (peginterferon alfa-2a)

There were some key differences between treatment arms: the ribavirin dose differed by product (Schering used a weight-based range of 800-1400 grams/day, while the Roche arm used a narrower weight-based range of 1000-1200 mg/day.  Also, ribavirin dose reductions (needed for people who developed anemia, a common side effect) were handled differently according to the product used (more drastic for the PEGASYS arm vs. the two PEG-INTRON arms).  There has not been enough data released yet to determine whether or not these differences had an effect on either response  or relapse rates, and if so, the magnitude  of the effect.

Based on the data released, there was no significant difference in efficacy between products. The sustained virological response rate (SVR) was 40% for the 1.5 PEG-INTRON arm and 41% in the PEGASYS arm. The treatment discontinuation rate from these 2 arms was the same– but the relapse rate was higher in the PEGASYS arm.


Neither Schering nor Roche (who also issued a press release about the results of IDEAL today [2]) should squander resources on a publicity war that does nothing to make HCV treatment more widely available to those who need it.

Results from IDEAL will be useful if they help to optimise HCV treatment—not if they are manipulated to favour one product or another.  To this end, Schering should not continue to focus on the relapse rate instead of the ultimate result: whether or not people clear the hepatitis C with treatment.

Shifting attention to a data point that appears favourable to Schering’s product may confuse providers and patients, and make HCV treatment decisions—which are already complex—more difficult.


  1. Schering press release: ‘Schering-Plough Reports Top-Line Results of the IDEAL Study’ 14 January 2008.
  2. Roche press release: ‘Roche responds to announcement of “IDEAL” hepatitis C study’ 14 January 2008.

Links to other websites are current at date of posting but not maintained.