Immunotherapy for Breast Cancer

What is immunotherapy for breast cancer?

Immunotherapy for breast cancer is treatment that helps your immune system attack and kill breast cancer cells. Healthcare providers now use immunotherapy to treat high-risk curable (early-stage) and metastatic triple-negative breast cancer.

Early stage means tests detect the tumors before they metastasize (spread). High-risk means tumors are likely to come back (recur) after treatment. Researchers are also evaluating immunotherapy as treatment for HER2-positive and ER-positive breast cancer.

How does immunotherapy for breast cancer work?

Immunotherapy trains your immune system so it can do more to find and kill cancer cells. It also helps your body produce cancer-fighting immune cells that find and destroy cancer cells. Breast cancer immunotherapy can be active or passive:

• Active immunotherapies are drugs that focus your immune system on breast cancer cells. To create these drugs, healthcare providers examine your breast cancer cells for antigens. Your healthy cells have antigens. So do intruders like cancer cells. Providers use what they learn about specific antigens to make drugs that focus your immune system on antigens in breast cancer cells.
• Passive immunotherapies are lab-made drugs that improve your immune system’s existing cancer-fighting tools.

What immunotherapy drugs treat breast cancer?

The U.S. Food and Drug Administration (FDA) has approved two immunotherapy drugs for breast cancer treatment: pembrolizumab and dostarlimab.

Pembrolizumab (Keytruda®)

Healthcare providers may use this drug to treat triple-negative breast cancer. This drug boosts your immune system’s response to cancerous cells. It also blocks a protein on cancer cells that lets the cells hide from your immune system. About 20% of triple-negative breast cancers have this specific protein. You may receive this medication before and after breast cancer surgery to reduce the risk that breast cancer will come back.

Providers may use pembrolizumab to treat metastatic breast cancer that is triple negative, but only if the breast cancer tumor carries specific tumor markers (biomarkers) that signal changes in your DNA that lead to cancer.

Dostarlimab (Jemperli®)

This drug treats metastatic breast cancer that’s spread during or after treatment and that has a specific tumor marker.

How would I receive immunotherapy?

Healthcare providers inject the drugs into your veins through an intravenous (IV) line. Specific treatment depends on your situation, but most people receive immunotherapy every three to six weeks for months up to two years.

What are the advantages of immunotherapy for breast cancer?

Immunotherapy is an effective option to improve the cure rate for triple-negative breast cancer. It’s also an option for certain metastatic breast cancers.

What’s the success rate for immunotherapy for breast cancer?

This treatment is relatively new and only approved to help people with high-risk triple-negative breast cancer and triple-negative metastatic breast cancer. One groundbreaking study showed people with triple-negative breast cancer who received the immunotherapy pembrolizumab and chemotherapy lived longer than people receiving chemotherapy alone.

There are hundreds of clinical trials evaluating different ways that immunotherapy may be a treatment for more types of breast cancer or different breast cancer stages. Immunotherapy treatments will continue to evolve as researchers learn more about ways the body’s immune system can slow breast cancer’s progress.

What are common side effects?

People react to immunotherapy in different ways. If you’re receiving immunotherapy, ask your healthcare provider what you can expect. Some common immunotherapy side effects are:

• Diarrhea.
• Fatigue.
• Skin rash.
• Thyroid issues.

Other, more serious side effects occur less often:

• Infusion reactions: Symptoms may include fever, chills, itchy skin, feeling dizzy or a flushed face. You might have trouble breathing or begin to wheeze.
• Autoimmune reactions: Sometimes, your immune system starts to attack other areas of your body, causing a variety of issues.

When should I see my healthcare provider?

Ask your healthcare provider to explain potential side effects and when you should contact them.