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Antiviral Interferons
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Agents: pegylated interferon-a 2a, pegylated
interferon-a 2b, interferon-a 2a, interferon-a 2b
Interferons are normal human cytokines, used by
the immune system to activate cells when infection
is present, fight cancerous cells, and other functions.
They are given exogenously in the treatment
of multiple diseases, ranging from multiple sclerosis
to cancers to viral hepatitis. Interferon-a 2a and
2b and their pegylated forms have all been used for
the treatment of both viral hepatitis B and C infections,
though only pegylated forms are currently
recommended.
Mechanism of Action
Interferons have multiple mechanisms of action
against hepatitis B and C viruses. They have direct
antiviral effects, change cellular differentiation,
inhibit cell growth, activate macrophages, and
increase lymphocyte cytotoxicity. Pegylated forms
of interferon have had molecules of polyethylene
glycol (PEG) attached to the interferon molecules
to improve their pharmacokinetics by increasing
their half-lives, allowing for decreased administration
frequency.