What is the most important information I should know about WELIREG?

WELIREG may cause serious side effects, including:

Low red blood cell count (anemia):

Low red blood cell count is common with WELIREG and may be serious. If the red blood cell count drops too low, a blood transfusion may be needed. Your healthcare provider will do blood tests to check your red blood cell count before you start using WELIREG and during treatment with WELIREG. Tell your healthcare provider if you have any symptoms of a low red blood cell count, including fatigue, feeling cold, shortness of breath, chest pain, or a fast heartbeat.

Low oxygen levels in your body:

WELIREG can cause severe low oxygen levels in your body, which may require you to stop WELIREG treatment, receive oxygen therapy, or be hospitalized. Your healthcare provider will monitor your oxygen levels before you start using WELIREG and during treatment with WELIREG. If you have symptoms of a lack of oxygen in your body, including shortness of breath or a rapid heart rate, tell your healthcare provider or seek medical help right away.

Harm to an unborn baby:

Treatment with WELIREG during pregnancy may cause harm to an unborn baby.

Women who are able to become pregnant:

Before you start treatment with WELIREG, your healthcare provider will perform a pregnancy test.

You should use effective non-hormonal birth control (contraception) during treatment with WELIREG and for 1 week after your last dose.

Birth control methods that contain hormones (such as birth control pills, injections, or transdermal patches) may not work as well during treatment with WELIREG.

Talk with your healthcare provider about the birth control methods that are right for you during treatment with WELIREG.

If you become pregnant or think you may become pregnant during treatment with WELIREG, tell your healthcare provider promptly.

Men with a female partner who is able to become pregnant:

You should use effective contraception during treatment with WELIREG and for 1 week after your last dose.

If your partner becomes pregnant or thinks she is pregnant while you are taking WELIREG, tell your healthcare provider right away.