Pegylated interferon: new preparation. Chronic hepatitis C: advantageous for some patients, but more data needed

(1) Three versions of interferon alfa are marketed in France for the treatment of chronic hepatitis C, namely alfa-2a, alfa-2b, and alfacon-1. When used in combination with ribavirin, the three drugs have similar risk-benefit ratios. (2) Two pegylated forms are now also available, namely peginterferon alfa-2a and peginterferon alfa-2b. (3) The clinical evaluation dossier contains data from four trials comparing peginterferon alfa alone with standard interferon alfa alone, and two trials comparing peginterferon alfa + ribavirin combinations with standard interferon alfa + ribavirin. (4) In terms of virological and biochemical outcomes, the peginterferon was more effective than the corresponding standard interferon when either drug was used alone. (5) In patients infected with genotype 1 hepatitis C virus, and a low viral load, the peginterferon + ribavirin combination was more effective than the standard interferon + ribavirin combination at reducing viral load below the limits of detection. (6) Pending comparative trials, there is no evidence of any difference in efficacy between peginterferon alfa-2a and peginterferon alfa-2b. (7) It is not yet clear whether peginterferon has any favourable impact on hepatic histological outcomes compared with standard interferon. (8) Except for a dose-dependent increase in the risk of neutropenia, the safety profile of peginterferon does not seem markedly different from the safety profile of standard interferon. (9) Like standard interferon alfa, peginterferon alfa is injected subcutaneously, but only once a week (instead of three times a week). (10) The use of peginterferon alfa-2 in France multiplies drug costs by a factor of three compared with standard interferon alfa-2. (11) In practice, the use of peginterferon alfa instead of standard interferon alfa is justified mainly for patients infected with genotype 1 who have a low viral load. Other patients may appreciate the smaller number of injections.