Targeted Drug Therapy for Soft Tissue Sarcoma

Targeted therapy drugs attack parts of cancer cells that make them different from normal, healthy cells. These drugs work differently from standard chemotherapy drugs, and they often have different types of side effects. Each type of targeted therapy works differently, but all of them affect the way a cancer cell grows, divides, repairs itself, or interacts with other cells.

As doctors learn more about the biology of sarcoma cells, targeted therapy is becoming an important treatment option for some soft tissue sarcomas.

Pazopanib (Votrient)

Pazopanib blocks several cell enzymes called tyrosine kinases that are important for cell growth and survival. It may be used to treat certain advanced soft tissue sarcomas that have not responded to chemotherapy. It can help slow tumor growth and ease side effects in patients with sarcomas that cannot be removed with surgery. So far, though, it's not clear that this drug helps people live longer.

Pazopanib is taken in pill form, once a day.

Side effects

Common side effects include high blood pressure, fatigue, nausea, diarrhea, headaches, changes in hair color, low blood cell counts, and liver problems. In some patients this drug causes abnormal results on liver function tests, but it rarely leads to severe liver damage that can be life threatening.

Bleeding, clotting, and wound healing problems are rare, but can occur as well. This drug also rarely causes a problem with the heart rhythm or even a heart attack.

If you're taking pazopanib, your doctor will monitor your heart with EKGs and do blood tests to check for liver problems or other changes.

Tazemetostat (Tazverik)

Tazemetostat works by targeting EZH2, a protein known as a methyltransferase that normally helps some cancer cells grow. This drug can be used to treat epithelioid sarcomas that can’t be removed completely by surgery. It can shrink or slow the growth of some of these cancers, although it’s not yet clear if it can help people live longer.

This drug is taken as pills, typically twice a day.

Side effects

The most common side effects of this drug include pain, fatigue, nausea, vomiting, loss of appetite, and constipation. Tazemetostat can also increase the risk of developing some types of blood cancers, including certain leukemias and lymphomas.

Other targeted drugs

Many other targeted drugs might also be helpful in treating certain types of soft tissue sarcomas. Examples of these drugs include:

• Regorafenib (Stivarga)
• Sorafenib (Nexavar)
• Sunitinib (Sutent)
• Larotrectinib (Vitrakvi) (for tumors with an NTRK gene change)
• Entrectinib (Rozlytrek) (for tumors with an NTRK gene change)
• Sirolimus albumin-bound nanoparticles (also known as nab-sirolimus or Fyarro) (for advanced malignant PEComas)