Targeted therapy for soft tissue sarcoma

Targeted therapy uses drugs to target specific molecules (such as proteins) on cancer cells or inside them. These molecules help send signals that tell cells to grow or divide. By targeting these molecules, the drugs stop the growth and spread of cancer cells and limit harm to normal cells. Targeted therapy may also be called molecular targeted therapy.

Some people with soft tissue sarcoma have targeted therapy. If you have targeted therapy, your healthcare team will use what they know about the cancer and about your health to plan the drugs, doses and schedules.

You may have targeted therapy to:

• treat metastatic (cancer that has spread) or recurrent soft tissue sarcoma
• relieve pain or control the symptoms of metastatic soft tissue sarcoma (called palliative therapy)

Different types of targeted therapy are used for soft tissue sarcoma.

Tyrosine kinase inhibitors (TKIs) block chemicals called tyrosine kinases. These chemicals are part of the signalling process within cells. When this process is blocked, the cancer cells stop growing and dividing.

Pazopanib (Votrient) is a TKI that blocks multiple kinase proteins including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR) and fibroblast growth factor receptor (FGFR). These proteins help cells form new blood vessels. Pazopanib works by finding and attaching to these proteins and preventing cancer cells from forming new blood vessels that they need to grow. It’s also considered a type of angiogenesis inhibitor.

You may be offered pazopanib for metastatic soft tissue sarcoma if cancer didn’t respond to or continued to grow after treatment with chemotherapy.

Imatinib (Gleevec) is a TKI that targets many different proteins including the KIT protein, which helps cells grow, divide and move around.

Imatinib may be used for unresectable, recurrent or metastatic dermatofibrosarcoma protuberans (DFSP).

Pazopanib and imatinib are taken once daily as a pill by mouth (orally).

Neurotrophic tyrosine receptor kinase (NTRK) inhibitors are drugs that inhibit abnormal NTRK proteins called TRK fusion proteins.

The gene for NTRK tells nerve cells to make a protein that helps them send information about certain bodily sensations. When part of the NTRK gene breaks off and joins with another gene, itʼs called an NTRK gene fusion. This change causes abnormal proteins called TRK fusion proteins, which may cause cancer cells to grow.

Larotrectinib (Vitrakvi) and entrectinib (Rozlytrek) are types of NTRK inhibitors. You may be offered larotrectinib or entrectinib for metastatic soft tissue sarcoma if all of the following apply:

• the cancer has a NTRK fusion mutation
• the cancer didnʼt respond to other treatment with other drug therapies
• the cancer can’t be treated with surgery

Larotrectinib and entrectinib are taken once daily as a pill by mouth (orally).

Side effects of targeted therapy will depend mainly on the type of drug or combination of drugs, the dose, how it’s given and your overall health. Tell your healthcare team if you have side effects that you think are from targeted therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

All drugs, including those used to treat cancer, are approved for use in Canada by Health Canada. If a drug is mentioned on cancer.ca, it means that Health Canada has approved the drug and pharmaceutical companies sell it in Canada. It does not mean that the drug is offered everywhere in Canada.

Paying for drugs is the responsibility of provincial and territorial health departments. Each health department makes its own decisions about which drugs to cover (pay for) in that province or territory. This means that a drug may be covered in one province, but not in others.

Your oncologist will talk to you about different drug treatments and what is available through your provincial or territorial drug program.

Find out more about targeted therapy. To make the decisions that are right for you, ask your healthcare team questions about targeted therapy.