Immunotherapy for Kaposi Sarcoma

Immunotherapy is the use of medicines to help your own immune system recognize and destroy cancer cells more effectively. It is sometimes used as part of treatment for Kaposi sarcoma (KS).

Immunomodulating drugs (IMiDs)

Immunomodulatory drugs (IMiDs) affect the immune system, although exactly how they do this isn’t entirely clear.

IMiDs are taken daily as pills, with breaks from treatment on certain days each month. Because these drugs can increase the risk of serious blood clots, they are often given along with aspirin or a blood thinner.

IMiDs might cause severe birth defects when taken during pregnancy, so you can only get them through a special program run by the drug company that makes them.

Pomalidomide (Pomalyst)

Pomalidomide is most often used after chemo has been tried. It can be used to treat people with KS who:

• Have HIV but whose KS is no longer responding to antiretroviral therapy (ART) alone
• Are HIV negative

Possible side effects: Some common side effects of pomalidomide include low blood counts (red blood cells, white blood cells, and platelets), kidney problems, rash, constipation, low phosphate or calcium levels, nausea, and diarrhea.

Lenalidomide (Revlimid)

Lenalidomide might be used in some people with KS that has come back or keeps growing on other drugs.

Possible side effects: The most common side effects of lenalidomide are low blood platelet counts and low white blood cell counts. It can also cause painful nerve damage.

Immune checkpoint inhibitors

An important part of the immune system is its ability to keep itself from attacking normal cells in your body. To do this, it uses “checkpoint” proteins on immune cells, which act like switches that need to be turned on or off to start an immune response. Cancer cells sometimes use these checkpoints to avoid being attacked by the immune system.

Drugs called immune checkpoint inhibitors target these checkpoint proteins. This can help restore your body’s immune response against Kaposi sarcoma cells.

PD-1 inhibitors

PD-1 is a checkpoint protein on immune cells called T cells. Drugs that target PD-1 can often boost the immune response against cancer cells. Examples of PD-1 inhibitors include:

• Pembrolizumab (Keytruda, Keytruda Qlex)
• Nivolumab (Opdivo, Opdivo Qvantig)

These drugs can be infused into a vein (IV) or given as an injection under your skin, typically every 2 to 6 weeks.

Either of these drugs might be an option to treat KS, typically after other treatments like chemo have been tried. They are not FDA approved specifically to treat KS, but doctors can prescribe them off label based on promising results from small studies of their use in KS.

These drugs can have major effects on the immune system, so they need to be used carefully in people with KS, especially people with AIDS or people who’ve had organ transplants.

Possible side effects of immune checkpoint inhibitors

Side effects of these drugs can include fatigue, cough, nausea, skin rash, poor appetite, constipation, and diarrhea.

Other, more serious side effects occur less often.

Infusion reactions:  Some people might have an infusion reaction while getting one of these drugs. This is like an allergic reaction. It can include fever, chills, flushing of the face, rash, itchy skin, feeling dizzy, wheezing, and trouble breathing. Tell your treatment team right away if you have any of these symptoms while getting these drugs.

Autoimmune reactions: These drugs remove one of the safeguards on your body's immune system. Sometimes the immune system starts attacking other parts of the body, which can cause serious or even life-threatening problems in your lungs, intestines, liver, hormone-making glands, kidneys, or other organs.

It’s very important to report any new side effects to your health care team quickly. If serious side effects do happen, your treatment may need to be stopped and you may get high doses of corticosteroids to suppress your immune system.

To learn more, see Immune Checkpoint Inhibitors and Their Side Effects.