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Managing Cancer Care

Immunomodulators and Their Side Effects

Immunomodulators are a group of drugs that mainly target the pathways that treat multiple myeloma and a few other cancers. They have many ways to work, including working on the immune system directly by turning down some proteins and turning up others.

Thalidomide, lenalidomide, and pomalidomide

Thalidomide (Thalomid), lenalidomide (Revlimid), and pomalidomide (Pomalyst) are known as immunomodulating drugs (or IMiDs).

These drugs can cause side effects such as drowsiness, fatigue, constipation, low blood cell counts, and neuropathy (painful nerve damage). There is also an increased risk of serious blood clots (that start in the leg and can travel to the lungs). These tend to be more likely with thalidomide than with the other drugs.

These drugs can also cause severe birth defects if taken during pregnancy.

Bacillus Calmette-Guérin

Bacillus Calmette-Guérin (BCG) is a germ that doesn’t cause serious disease in humans, but it does infect human tissues and helps activate the immune system. This makes BCG useful as a form of cancer immunotherapy. BCG was one of the earliest immunotherapies used against cancer and is still being used today.

BCG is used to treat early stage bladder cancer. It is a liquid put into the bladder through a catheter. BCG attracts the body’s immune system cells to the bladder, where they can attack the bladder cancer cells. Treatment with BCG can cause symptoms that are like having the flu, such as fever, chills, and fatigue. It can also cause a burning feeling in the bladder. BCG can also be used to treat some melanoma skin cancers by injecting it directly into the tumors. It's also used as a vaccine against tuberculosis.


Imiquimod is a drug that is applied to the skin as a cream. It stimulates a local immune response against skin cancer cells. It is used to treat some very early stage skin cancers (or pre-cancers), especially if they are in sensitive areas such as on the face.

The cream is applied anywhere from once a day to twice a week for several months. Some people have serious skin reactions to this drug.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

American Society of Clinical Oncology (ASCO). ASCO Annual Meeting 2019: Immunotherapy for lung cancer, gastrointestinal cancers and targeted therapy for breast cancer. Accessed at on December 19, 2019.

American Society of Clinical Oncology (ASCO). Understanding immunotherapy. Accessed at on December 19, 2019.

Bayer VR, Davis ME, Gordan RA, et al. Immunotherapy. In Olsen MM, LeFebvre KB, Brassil KJ, eds. Chemotherapy and Immunotherapy Guidelines and Recommendations for Practice. Pittsburgh, PA: Oncology Nursing Society; 2019:149-189.

Brodsky AN. Cancer immunotherapy: The year in review and a look at the year ahead. Cancer Research Institute. Accessed at on December 19, 2019.

Hafeez U, Gan HK, Scott AM. Monoclonal antibodies as immunomodulatory therapy against cancer and autoimmune diseases. Curr Opin Pharmacol. 2018; 41:114-121.

Wraith DC. The future of immunotherapy: A 20-year perspective. Front Immunol. 2017:8:1668. Accessed at on December 19, 2019.

Last Revised: December 27, 2019

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