Pegasys (peginterferon alfa-2a)


Approval Status
Approved October 2002

Treatment for
Hepatitis C

Gastrointestinal , Immune System

Pegasys (peginterferon alfa-2a) was approved in October 2002 for the treatment of adults with chronic hepatitis C who have compensated liver disease and have not previously been treated with interferon alpha, including patients with compensated cirrhosis. Pegasys is a pegylated interferon that remains active in the bloodstream longer and at a more constant level than interferon alpha.

Pegasys is available as premixed solution. It is administered at a dose of 180 ug as a subcutaneous injection once a week for a recommended duration of 48 weeks.

Three pivotal phase III clinical studies of Pegasys demonstrated that the sustained virological response (defined as undetectable serum hepatitis C RNA levels post-treatment [on or after study week 68]) in the Pegasys treated subjects was as high as 38% in the overall population versus 19% in the interferon alfa-2a group. Subjects with cirrhosis who were treated with Pegasys showed a sustained virological response as high as 30% versus 8% in the interferon alfa-2a group. Subjects with genotype 1 treated with Pegasys showed showed a sustained virological response of up to 23%, compared to 6% in the interferon alfa-2a group.

In addition, studies indicated that it can be determined at week 12 of treatment whether a subject is unlikely to attain a sustained virological response with Pegasys. This could prevent subjects from continuing a therapy to which they will most likely be unresponsive.

In clinical studies, the following adverse events were reported most often:

  • Headache
  • Fatigue
  • Myalagia
  • Pyrexia
  • Rigors
  • Arthralgia
  • Nausea
  • Alopecia
  • Injection-site reaction
  • Neutropenia
  • Insomnia
  • Depression
  • Anorexia
  • Irritability

Alpha interferons, including Pegasys, may cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders.

Pegasys is produced when interferon alfa-2a undergoes the process of pegylation in which one or more chains of polyethylene glycol (also known as PEG) are attached to another molecule. In Pegasys, a large, branched, mobile PEG is attached to the interferon alfa-2a molecule, providing a selectively protective barrier against rapid absorption, metabolism and elimination. At the same time, the PEG maintains the ability of the interferon alfa-2a to attack the virus.

For further information about Pegasys, please visit the Roche web site at

Pegasys (peginterferon alfa-2a) Drug Information

The Pegasys (peginterferon alfa-2a) drug information shown above is licensed from Thomson CenterWatch. The information provided here is for general educational purposes only and does not constitute medical or pharmaceutical advice which should be sought from qualified medical and pharmaceutical advisers.

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