Monoclonal antibodies are immune system proteins that are created in a lab. Antibodies are produced by your body and help the immune system recognize germs that cause illness and mark them for destruction.

Like your body’s own antibodies, monoclonal antibodies recognize specific targets called antigens. Monoclonal antibodies are made to target antigens on the surface of cancer cells, leading to their death. 

How Monoclonal Antibodies Work

There are many types of monoclonal antibodies. Each one binds to specific targets on a cancer cell for different reasons.

Below are a few goals monoclonal antibody treatments may have: 

• Flagging the cancer cells: A monoclonal antibody may bind to the surface of cancer cells like a target and make it easily detectable by the body’s immune system.  

• Blocking growth or blood supply of cancer cells: By binding to specific areas on a cancer cell, monoclonal antibodies can block the cell from other proteins it needs to grow. 

• Blocking immune system inhibitors: Antigens can create “checkpoints” on the surface of a cancer cell that can block the body’s natural immune system, helping the cancer stay hidden. Monoclonal antibodies can block these checkpoints so the immune system can identify and attack cancer. These monoclonal antibodies are referred to as “checkpoint inhibitors.” 

• Guiding other treatments: Monoclonal antibodies can work in tandem with some chemotherapy or radiation treatments. These types of monoclonal antibodies help guide the radiation or chemotherapy directly to the cancer cells allowing for more targeted treatment and fewer toxic side effects.  

Good to Know

Biosimilars are medicines that are highly similar to their originating, or interchangeable, biologic medicines and are used to treat the same diseases. Biosimilars have similar types of side effects as the reference medication and are less expensive. 

When Monoclonal Antibodies Are Used

Not all cancers currently benefit from monoclonal antibody therapies. In most cases, your provider will use specific lab tests taken from the tumor sample to determine if any targeted treatments are available for your cancer type. If those results are positive, monoclonal antibody treatment may be given at an infusion center through an IV or implanted port.  

Possible Side Effects 

The benefit of monoclonal antibody therapy is that because it is targeted directly at cancer cells, it is less toxic to normal cells, and therefore has fewer side effects.

Despite being less frequent and severe, there are still some potential side effects that may occur including: 

• Rash 

• Diarrhea

• Fatigue

• Fever or chills 

• Dizziness 

• Headache 

• Nausea and vomiting

• Low blood pressure 

Infusion reactions may occur during treatment for some patients. Your nurse will closely monitor you for symptoms of flushing, shortness of breath, weakness, or dizziness.  

Questions to Ask Your Provider

• Has my cancer been tested to see if monoclonal antibody therapy may benefit me? 

• Do the benefits of this treatment outweigh the risks? 

• What side effects can I expect from this treatment? 

• What will the cost of this treatment be for me? 

• Are there any monoclonal antibody clinical trials I would be a good fit for? 

• Will I be receiving a biosimilar?