This medication may cause very serious (rarely fatal) blood disorders (decreased bone marrow function leading to low number of blood cells such as red cells, white cells, and platelets). This effect can cause anemia, decrease your body's ability to fight an infection, or cause easy bruising/bleeding. Tell your doctor right away if you develop any of the following symptoms: signs of infection (such as sore throat that doesn't go away, fever, swollen lymph nodes), easy bruising/bleeding, coughing up blood, shortness of breath, unusual tiredness, fast/pounding heartbeat.

Serious (rarely fatal) infusion reactions may happen during the infusion of this drug and for a short time afterward. These reactions occur more often during the first week of treatment. Your doctor will prescribe other medications (such as acetaminophen, diphenhydramine, corticosteroids) before each treatment to help prevent these side effects. Tell your doctor right away if you have any symptoms of infusion reactions such as fever, chills, flushing, dizziness, shortness of breath, nausea, vomiting, or mild rash/itching. Your doctor may give you other medications to help with these side effects.