What are the side effects of monoclonal antibodies?

The side effects of monoclonal antibodies differ from person to person, but there are some common ones.

Like most immunotherapy, monoclonal antibodies can cause skin reactions at the needle site, such as pain, swelling, soreness, redness, itchiness, and rash. They can also cause flu-like symptoms, including chills, fatigue, fever, muscle aches and pains, nausea, vomiting, and diarrhea.

Less commonly, they can cause more serious problems. These include mouth and skin sores that can lead to infections, high blood pressure, heart problems, and inflammatory lung disease. They can also cause mild to severe allergic reactions during treatment, and rarely a reaction can be life-threatening. Some can cause capillary leak syndrome or cytokine release syndrome.

Doctors cannot know for sure when or if side effects will happen, so it is important to know the warning signs and tell your care team right away if you feel unwell.