Immunotherapy Side Effects

October 24, 2024

This page was reviewed under our medical and editorial policy by Alexis Boling, MSN-RN, CNML, director, nursing, Immune Effector Cell & Gene Therapy Program, City of Hope^® Cancer Center Duarte

Immunotherapy is a type of cancer treatment in which substances made in a laboratory or by the patient’s own body are deployed to boost the immune system and help it find and destroy cancer cells. While immunotherapy is an appropriate treatment option for many cancers, it may also cause side effects.

The side effects of immunotherapy and other treatments, like chemotherapy, are different because of how these treatments work. Traditional chemotherapy treatments typically target fast-growing cancer cells directly, although they can still affect some healthy fast-growing cells, such as the hair follicles (hair loss) and the digestive tract (nausea). In contrast, immunotherapy uses a “middleman,” the immune system, and side effects occur because treatments may cause the immune system to mistakenly attack healthy cells as well as cancer cells.

Immunotherapy side effects may vary widely for each patient. Some people might experience mild side effects or ones that are only noticeable through medical tests. Others might experience more severe or even life-threatening side effects.

Common Side Effects of Immunotherapy

The specific side effects depend on the type of immunotherapy, the type of cancer, its location, the patient’s general health and other factors. In general, here are some common side effects listed by type of immunotherapy.

Immune checkpoint inhibitors: These immunotherapy therapies help stop cancer cells from blocking the immune system, giving it a better chance to respond to disease. Common side effects from immune checkpoint inhibitors such as Keytruda^® (pembrolizumab), Opdivo^® (nivolumab) or Yervoy^® (ipilimumab) may include:

• Skin rashes or itching
• Digestive problems, such as diarrhea, nausea or vomiting
• Arthritis-like joint pain or swelling
• Harm to other areas of the body, such as the kidney, lungs, heart, eyes and other organs

Chimeric antigen receptor (CAR) T cell therapy: This type of immunotherapy involves genetically modifying a patient’s own T cells in a laboratory and returning them to the body, where they help stimulate the immune system to attack cancer cells. Side effects from CAR T cell therapies such as Kymriah^® (tisagenlecleucel) or Yescarta^® (axicabtagene ciloleucel) may include:

• Cytokine release syndrome (fast heart rate, low blood pressure, fever, nausea, headache, rash)
• Immune effector cell-associated neurotoxicity syndrome (confusion, trouble speaking, muscle weakness, headache, seizures)
• Infections
• Low blood levels of iron, platelets or white blood cells
• Bleeding or clotting problems

Monoclonal antibodies: These proteins may be used to mark cancer cells so the immune system may more easily recognize and destroy them. Side effects of monoclonal antibodies such as rituximab (sold under several brand names) or Blincyto^® (blinatumomab) may include:

• Injection site reactions (pain, redness, swelling or rash)
• Flu-like symptoms (fever, nausea, diarrhea, fatigue, chills, aches or pains)
• Mouth or skin sores
• High blood pressure
• Heart problems
• Allergic reactions

Tumor-infiltrating lymphocyte (TIL) therapy: TIL cells identify and damage cancer cells in solid tumors. Side effects of TIL therapy may include:

• High fever
• Anemia
• Low platelet counts
• Low white blood cell counts

Cancer treatment vaccines: These shots, which include Imlygic^® (talimogene laherparepvec) and Provenge^® (sipuleucel-T), stimulate the body’s natural defenses against cancer. These medications may cause side effects such as:

• Flu-like symptoms
• Allergic reaction
• Stroke (sipuleucel-T)
• Tumor lysis syndrome (talimogene laherparepvec), which is when tumor cells break apart and damage the kidneys, liver or heart
• Herpes virus infection (talimogene laherparepvec)

Immune system modulators: These drug treatments, such as Bacillus Calmette-Guérin (BCG) and Revlimid^® (lenalidomide), help enhance the immune system’s response to cancer. Possible side effects may include:

• Flu-like symptoms
• Cytokine side effects (skin problems, trouble breathing, allergic reactions, blood pressure problems, blood clots or low blood counts)
• Birth defects if used during pregnancy (lenalidomide)
• Urinary symptoms (BCG)

Everyone responds to immunotherapy differently. It is important for patients to speak with their health care team to learn about potential side effects, signs to watch out for and how any side effects may be managed.

Are Immunotherapy Side Effects Worse Than Chemotherapy?

The side effects of immunotherapy and chemotherapy are different because of how these treatments work. Chemotherapy targets and destroys rapidly dividing cancer cells, but it may also affect healthy cells. This often causes side effects like fatigue, hair loss and pain. These side effects may range from mild to severe, and usually start shortly after treatment begins.

Immunotherapy, on the other hand, boosts the immune system to help it attack cancer cells. This may cause the immune system to also attack healthy cells, leading to side effects that may appear during treatment or even years later. These side effects may be mild, moderate or life-threatening.

It is important for the patient to discuss any side effects with the health care team so they may be managed effectively.

Timeline of Immunotherapy Side Effects

Side effects from immunotherapy may occur at different times, and it is important to understand the possible timeline. Some side effects may appear right away during or shortly after the first treatment. For instance, patients may experience an infusion reaction, which is similar to an allergic reaction. Symptoms may include dizziness, flushing of the face, chills or fever, rash, itchy skin, wheezing and/or difficulty breathing. These early reactions may occur while the drug is being given, especially with treatments such as immune checkpoint inhibitors and monoclonal antibodies.

During the weeks following treatment, patients are closely monitored by their health care team for any side effects. 

However, side effects from immunotherapy may also develop much later. They may occur at any point during treatment and even up to two years after treatment ends. Long-term side effects of immunotherapy may sometimes include joint or muscle problems, known as rheumatologic issues. Those who are less physically active may be more likely to develop these conditions.

In addition, some immunotherapy treatments (such as checkpoint inhibitors) may affect vision. Patients may experience changes in their eyesight, watery or dry eyes, cataracts or glaucoma. Regular vision screenings and appointments with an ophthalmologist may help manage and monitor these changes.

Do Immunotherapy Side Effects Get Worse With Each Treatment?

Immunotherapy side effects do not necessarily get worse with each treatment, but some effects may become more noticeable or more severe over time. The key to managing them is early recognition and communication with the care team. These steps may help prevent or relieve many side effects, making treatment more tolerable.

Before starting immunotherapy, patients should ask the care team about possible side effects.

During treatment, it is important to report any new or worsening symptoms as soon as they appear, even if they seem minor. Early treatment of side effects may be more successful and may prevent them from becoming severe.

Treatment may be able to continue with close monitoring for mild side effects. If side effects are moderate to severe, the doctor might pause the treatment and prescribe medications, such as corticosteroids, to help manage them. A patient’s treatment plan may be adjusted based on how he or she responds to immunotherapy.

Managing Immunotherapy Side Effects at City of Hope

At City of Hope, our scientists are researching new approaches to immunotherapy to reduce side effects and make patients more comfortable. We provide comprehensive support to every patient to help manage any side effects they may experience and improve quality of life.

Learn more about our immunotherapy research