Peg-Intron (peginterferon alfa-2b)
The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Peg-Intron (peginterferon alfa-2b) Powder for Injection has been
approved by the FDA as a once-weekly monotherapy for the treatment
of chronic hepatitis C. It is indicated for patients with
compensated liver disease who were not previously treated with
alpha interferon. Peg-Intron is the first pegylated interferon to
be approved in the United States, and therefore offers a new
treatment option for hepatitis patients.
Peg-Intron is a longer-acting formulation of
Schering-Plough's Intron A, which is a recombinant version of a
naturally occurring alpha interferon. In contrast to Intron A,
which is administered three times weekly, Peg-Intron is
administered subcutaneously once a week. This reduced frequency of
administration may increase patient compliance.
Hepatitis C is a liver disease caused by the hepatitis C virus,
which is spread by contact with the blood of an infected person.
According to the Centers for Disease Control, approximately four
million Americans are infected with the hepatitis C virus and
approximately 70% of infected patients develop chronic liver
Peg-Intron was evaluated in a randomized, controlled trial that
included 1,219 adult subjects with chronic hepatitis C who were not
previously treated with alpha interferon. The trial compared
Peg-Intron (0.5, 1.0 or 1.5 mcg/kg) administered subcutaneously
once weekly to Schering-Plough's Intron A (recombinant
interferon alfa-2b) Injection (3 MIU) administered subcutaneously
three times weekly.
Treatment was administered for 48 weeks, and subjects were also
followed for 24 weeks post-treatment. Subjects receiving the 1.0
mcg/kg dose of Peg-Intron achieved a 24% treatment response rate of
sustained virologic response and ALT normalization, whereas a 12%
treatment response rate was observed in subjects receiving Intron
Alpha interferons such as Peg-Intron may cause serious
neuropsychiatric, autoimmune, ischemic and infectious disorders. As
a result, patients receiving treatment should be closely monitored,
and those with persistently severe or worsening signs or symptoms
of these conditions should discontinue therapy.
In clinical trials, nearly all subjects experienced one or more
adverse events. The most common adverse events associated with
Peg-Intron were "flu-like" symptoms, which occurred in
approximately 50% of subjects. Injection site irritation or
inflammation was seen in 47% of subjects, and depression was
reported in approximately 29% of subjects.
Mechanism of Action
Peg-Intron utilizes proprietary PEG technology developed by
Enzon. By linking recombinant interferon to a 12,000 dalton
polyethylene glycol (PEG) molecule, the anti-viral properties of
interferon can be sustained for a longer period of time.
Interferons bind to specific cell surface membrane receptors and
have been shown to exert antiviral and immunomodulatory effects.
After binding to the cell membrane, the glycoproteins initiate
intracellular events including the suppression of cell
proliferation, the enhancement of macrophage activity, and the
inhibition of viral replication in infected cells. (from Intron A