Pegasys (peginterferon alfa-2a)
The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
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
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
In clinical studies, the following adverse events were reported
- Injection-site reaction
Alpha interferons, including Pegasys, may cause or aggravate
fatal or life-threatening neuropsychiatric, autoimmune, ischemic,
and infectious disorders.
Mechanism of Action
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 www.roche.com.