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Interferon
Interferon is a protein that your body is constantly making, and your body makes even more interferon when it tries to fight off an infection, such as a virus. You've experienced this if you've ever had the flu. When you have the flu, your body makes extra interferon to defeat the virus that's causing the illness.
For some infections such as hepatitis C, patients can inject more interferon into their bodies to help fight the virus. While the interferon that's in a PEGASYS injection may be slightly different from the kind your body makes, it can help the body fight the virus in three ways:
- It helps healthy cells defend themselves against the virus.
- It helps the immune system stop the virus from multiplying.
- It helps the body get rid of infected cells (while continuing to prevent healthy cells from being infected).
Alpha interferons, including the form used in PEGASYS, have been known to cause a range of side effects. Continue reading for more information about PEGASYS.
PEGASYS and pegylation
PEGASYS is a branched pegylated interferon. Pegylation is the process of attaching one or more chains of a substance called polyethylene glycol (also known as PEG) to a protein molecule such as interferon. Interferon will be slowly released into your body, but it does not react to PEG. Thus, PEG helps provide a protective barrier around interferon so it can survive in the body longer.
When used with medications, this barrier may help provide benefits over molecules that are not pegylated. In the case of pegylated interferon, it stays in the bloodstream longer and is cleared by the body more slowly. That's what makes once-a-week, single-dose treatment possible. This added time in the body also appears to be responsible for the higher rates of sustained virologic response that were seen in patients whose chronic hepatitis C infections were treated with pegylated interferon compared with nonpegylated interferon.
To learn more about pegylation, see our animation.
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