IMPORTANT SAFETY INFORMATION

What is PEGASYS?

PEGASYS is a medicine used to treat some adults who have hepatitis C or hepatitis B and signs of liver damage. PEGASYS works to reduce the amount of virus in your blood, helping your body fight the virus.

PEGASYS (Peginterferon alfa-2a), like other alpha interferons, can cause fatal or make life-threatening problems worse (like mental, immune system, heart, liver, lung, intestinal and infections). Your doctor should monitor you during regular visits. If you show signs or symptoms of these conditions, your doctor may stop your medication. In most patients, these conditions get better after you stop taking PEGASYS (see medication guide for more information and warnings).

What is COPEGUS?

COPEGUS is a medicine that works by slowing down the growth of the virus. COPEGUS should be taken with PEGASYS to fight the virus. Do not take COPEGUS by itself.

COPEGUS (Ribavirin, USP) can be extremely harmful and cause birth defects in an unborn baby. Female patients and the female partners of male patients should avoid getting pregnant. Ribavirin is known to cause anemia (low red blood cells), which can make heart disease worse. Also, ribavirin can harm your DNA and possibly cause cancer (see medication guide for more information and warnings).

Who should not take PEGASYS and COPEGUS?

Do not take PEGASYS alone or with COPEGUS if:

• You are pregnant or your partner is pregnant
• You or your partner plans to get pregnant during therapy or within 6 months after treatment ends
• You are breastfeeding
• You have hepatitis caused by your immune system (autoimmune hepatitis)
• You have unstable or severe liver disease before or during treatment
• You are allergic to alpha interferons or any of the ingredients in PEGASYS and COPEGUS
• You have abnormal red blood cells (caused by conditions like sickle-cell anemia or thalassemia major)

What if I am pregnant or thinking about having a baby?

If you are a woman who could get pregnant, you must take pregnancy tests before, during and for 6 months after treatment ends to make sure you are not pregnant.

During treatment and for 6 months after treatment, female and male patients must:

• Use two forms of birth control (one being a condom with spermicide)
• Tell your doctor right away if you or your partner becomes pregnant. You or your doctor should also call the Ribavirin Pregnancy Registry at 1-800-593-2214

What medication should I avoid when I am taking PEGASYS and COPEGUS?

You should not take didanosine with COPEGUS. Talk to your doctor about all medications that you are taking.

What are the possible side effects?

The most common side effects of PEGASYS and COPEGUS are:

• Flu-like symptoms (including fever, chills, muscle aches, joint pain, headaches)
• Tiredness
• Upset stomach (like nausea, taste changes, diarrhea)
• Blood sugar problems (may lead to diabetes)
• Redness and swelling at injection site
• Skin problems (like rash, dry or itchy skin)
• Hair loss (temporary)
• Trouble sleeping

The most serious side effects of PEGASYS and COPEGUS are:

• Risks to pregnancies
• Mental health problems (such as irritability, depression, anxiety, aggressiveness, trouble with drug addiction or overdose, thoughts about suicide, suicide attempts, suicide, thoughts about homicide, and hallucinations)
• Blood problems (like a drop in blood cells leading to increased risk for infections, bleeding and/or heart or circulatory problems)
• Infections (which sometimes cause death)
• Lung problems (like trouble breathing, pneumonia)
• Eye problems (like blurred vision, loss of vision)
• Autoimmune problems (such as psoriasis, thyroid problems)
• Heart problems (including chest pain and, rarely, a heart attack)
• Liver problems (rarely, liver function worsens). Patients with both the hepatitis C virus and HIV can have an increased chance of having liver failure during PEGASYS treatment. Change in a blood test that measures liver inflammation occurs more often in patients with hepatitis B. If you have a rise in this blood test you may need to be watched more closely with additional blood tests.

Tell your doctor immediately if you think you or your partner may be pregnant or if any of these symptoms occur.