Targeted Therapy for Ewing Sarcoma

This type of treatment has been studied for Ewing sarcoma. So far, it's not clear if a stem cell transplant (SCT) works better than other treatments (such as standard chemotherapy), so most doctors only recommend it as part of a clinical trial. 

Tyrosine kinase inhibitors (TKIs)

TKIs work by blocking the signals cells need to grow and divide. Specifically, these drugs affect a tumor’s ability to grow new blood vessels, which it needs to grow and survive. Some examples of TKIs that have been tried in Ewing sarcoma treatment include:

• Regorafenib (Stivarga)
• Cabozantinib (Cabometyx)

Possible side effects

Side effects of these drugs can include fatigue, loss of appetite, hand-foot syndrome (redness and irritation of the hands and feet), high blood pressure, weight loss, diarrhea, and abdominal (belly) pain.

Less common but more serious side effects can include problems with blood flow to the heart, bleeding, abnormal thyroid test results, and perforations (holes) in the stomach or intestines.

Drugs targeting EWS:FLI fusion proteins

These drugs can block proteins that help cancer cells grow, divide, and repair damage. Blocking these proteins can lead to cell damage and death. Some examples of drugs that work against EWS:FLI fusion proteins include:

• Trabectedin (Yondelis)
• Lurbinectedin (Zepzelca)

Possible side effects

Side effects of these drugs can include low energy, changes in blood test results (blood salts, kidney, and liver testing), low blood counts, abdominal (belly) pain, nausea, vomiting, diarrhea, decreased appetite, and muscle or joint pains.

Trabectedin may cause heart or liver problems. It can also cause a problem with the muscles, which can be life-threatening (rhabdomyolysis).

Your cancer care team will watch closely for side effects while you are taking one of these drugs.

Other targeted drugs in clinical trials

Researchers are studying other ways to kill Ewing sarcoma cells. For example, lab studies of CDK inhibitors, like palbociclib and abemaciclib, and LSD1 inhibitors, like seclidemstat, have shown promise in treating Ewing sarcoma. Clinical trials on these drugs will continue.