Jemperli: What to Expect, Side Effects, and More

Jemperli (chemical name: dostarlimab-gxly) is a type of immunotherapy called an immune checkpoint inhibitor, which helps your body to recognize and attack cancer cells. 

The medicine is approved to treat mismatch repair deficient (dMMR) advanced-stage breast cancer that has grown during or after treatment if no other treatment options are available.

See Jemperli prescribing information.

Jemperli is a type of immunotherapy called an immune checkpoint inhibitor. The medicine helps your body to recognize and attack cancer cells. 

Immune checkpoints are proteins in your body that help your immune system tell the difference between your own cells and foreign invaders, such as harmful bacteria. Cancer cells sometimes find ways to use these immune checkpoint proteins as a shield to avoid being identified and attacked by the immune system.

PD-1 is a type of checkpoint protein found on T cells, which are part of the immune system. T cells look for signs of disease or infection in the body. PD-L1 is another checkpoint protein found on many healthy cells in the body. When PD-1 binds to PD-L1, it stops T cells from killing a cell.

Still, some cancer cells have a lot of PD-L1 on their surface, which stops T cells from killing these cancer cells. Jemperli stops PD-1 from binding to PD-L1, which signals  T cells to attack the cancer cells.

Jemperli is given intravenously. You receive the first four 30-minute infusions every three weeks. After that, you receive the remaining doses every six weeks.

Like almost all breast cancer medicines, Jemperli can cause side effects, some of them severe.

The most common side effects of Jemperli are:

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  fatigue

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  weakness

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  low red blood cell counts (anemia)

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  diarrhea

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  nausea

Other serious side effects include:

Pneumonia (inflammation or fluid in one or both lungs): Pneumonia can be a serious and sometimes life-threatening condition. Symptoms include trouble breathing, cough, and chest pain.

Colitis (inflammation of the inner lining of the colon): Symptoms include diarrhea, blood or mucus in your stool, and severe stomach pain.

Liver problems: Jemperli may cause hepatitis (inflammation of the liver). Tell your doctor right away if you have yellowing of your skin or the whites of your eyes, dark-colored urine, bleeding or bruising more easily than normal, severe nausea or vomiting, or pain on the right side of your stomach area.

Hormone gland problems: Jemperli may affect glands that make certain hormones your body needs to function properly, including the thyroid, adrenal glands, pancreas, and pituitary gland. Symptoms include headaches that won’t go away, extreme tiredness, weight gain or loss, changes in mood or behavior, feeling cold, and constipation.

Skin problems: Jemperli may cause life-threatening inflammation of the skin and mucous membranes. Tell your doctor right away if you develop a painful rash and blisters that peel and weep. Your skin also may be itchy, red, and scaly.

Severe infection: Symptoms include fever, cough, flu-like symptoms, pain when urinating, or back pain.

You should not take Jemperli if you’re pregnant or nursing. You should use contraception during your treatment and for 4 months after your last dose.

The cost of Jemperli may vary. The price you’ll pay depends on the drug manufacturer, your health insurance provider and plan, where you live, and the pharmacy you use. You may also be charged for the office visits required for Jemperli infusions.

Note: Your insurance company may require you to get prior authorization before covering Jemperli. 

Together with GSK Oncology is a patient assistance program that can help manage the cost of Jemperli.

Learn more about financial assistance and medicine cost-lowering tips.