Targeted Therapy for Thymus Cancer

In recent years, doctors have started using newer, targeted drugs to treat thymus cancer. Targeted therapy drugs work to destroy cancer cells or slow down their growth. Targeted drugs work differently than other drugs to treat cancer, and they often cause different side effects too.

When is targeted therapy used?

Targeted therapy drugs work differently from chemotherapy (chemo) drugs. Standard chemo works by attacking rapidly growing cells, including cancer cells. Targeted therapy drugs instead attack specific gene and protein changes inside thymus cancer cells.

For thymus cancers, targeted therapy is mainly used for thymic carcinoma. In some cases, it may be used for type B3 thymoma. It is mostly used after cancer has stopped responding to chemotherapy or for tumors that can't be treated with surgery or radiation. It's typically tried after other treatments have already been used.

Multikinase inhibitors

Kinases are proteins in cells that act like switches, turning cell functions on and off. Kinase inhibitors are drugs that block these proteins. Multikinase inhibitors can block many of these proteins at once. This can slow or stop cancer from growing.

Multikinase inhibitors work in two main ways. They:

• Help block tumors from forming the new blood vessels they need to grow
• Target proteins that help cancer cells grow and divide

Multikinase inhibitors for thymic carcinoma

Sunitinib (Sutent) and lenvatinib (Lenvima) have both helped to shrink tumors or stop them from growing for a period of time for some people with thymic carcinoma. Of the targeted drugs studied for thymic carcinoma so far, lenvatinib has shown some of the most promising results.

Both drugs are taken by mouth as a pill, once a day.

Side effects

Common side effects can include fatigue, rash, loss of appetite, diarrhea, nausea, and high blood pressure. It can also cause hand-foot syndrome, which causes redness, pain, swelling, or blisters on the palms of the hands or soles of the feet.

Other, more serious side effects can also occur, such as severe bleeding or holes forming in the intestine.

Angiogenesis inhibitors

For tumors to grow, they need to form new blood vessels to stay nourished. Growing new blood vessels is a process called angiogenesis. Angiogenesis inhibitors block this process.

Many of these drugs target a protein called vascular endothelial growth factor (VEGF), which helps new blood vessels form. Drugs that block VEGF or its receptor are sometimes called VEGF inhibitors.

Angiogenesis inhibitors for thymus cancers

• Axitinib (Inlyta) blocks the VEGF receptor. It has been studied in combination with an immunotherapy drug (avelumab) for advanced thymic carcinoma and type B3 thymoma. The results are encouraging in people who had already been treated with chemotherapy.

Axitinib is taken by mouth as a pill, typically twice a day.

• Ramucirumab (Cyramza) is a monoclonal antibody that also blocks angiogenesis. It targets a VEGF receptor called VEGFR2. It's being studied in combination with chemotherapy (carboplatin and paclitaxel) as a possible first treatment for thymic carcinoma. Early results suggest it may help the chemotherapy work better.

Ramucirumab is given as an infusion into a vein (IV). It is usually combined with chemotherapy on a treatment schedule of cycles with rest periods in between to let the body recover.

Side effects

Common side effects can include nosebleeds, headaches, high blood pressure, protein in the urine, changes in taste, and dry skin.

Rare, but serious side effects can include:

• Severe bleeding
• Holes (perforations) forming in the intestine
• Problems with wound healing
• Blood clots
• Rare brain condition called reversible posterior leukoencephalopathy syndrome (RPLS)
• Very high blood pressure
• Kidney damage
• Allergic (infusion) reactions to the drug
• Thyroid problems
• Ovarian failure

mTOR inhibitors

mTOR inhibitors block a protein called mTOR. This protein helps cells grow and divide. This drug may also help stop tumors from forming new blood vessels, which can further limit tumor growth.

mTOR inhibitor used for thymic carcinoma

Everolimus (Afinitor) has been studied in people with thymic carcinoma whose cancer had already been treated. It has shown it can help control the disease for a period of time in some people.

Everolimus is taken by mouth as a pill.

Side effects

Common side effects can include mouth sores, fatigue and weakness, skin rash, loss of appetite, nausea and diarrhea, and swelling that often happens in the legs or feet.

Everolimus can also affect blood counts and metabolism. It can cause low red and white blood cell counts, low platelet counts, high blood sugar, and high cholesterol or triglyceride levels.

Rare, but serious side effects include lung inflammation (pneumonitis), which can cause cough or shortness of breath. It can affect the immune system, causing an increased risk of infection. And it can cause kidney problems.

More information about targeted therapy

To learn more about how targeted drugs are used to treat cancer, see Targeted Cancer Therapy.

To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.