MONJUVI may cause serious side effects, including Infusion reactions. Your healthcare provider will monitor you for infusion reactions during your infusion of MONJUVI. Tell your healthcare provider right away if you get fever, chills, flushing, headache, or shortness of breath during an infusion of MONJUVI. Low blood cell counts (platelets, red blood cells, and white blood cells). Low blood cell counts are common with MONJUVI, but can also be serious or severe. Your healthcare provider will monitor your blood counts during treatment with MONJUVI. Tell your healthcare provider right away if you get a fever of 100.4 °F (38 °C) or above, or any bruising or bleeding. Infections. Serious infections, including infections that can cause death, have happened in people during treatment with MONJUVI and after the last dose. Tell your healthcare provider right away if you get a fever of 100.4 °F (38 °C) or above, or develop any signs or symptoms of an infection. The most common side effects of MONJUVI include feeling tired or weak diarrhea cough fever swelling of lower legs or hands respiratory tract infection decreased appetite These are not all the possible side effects of MONJUVI. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.