Keytruda (Pembrolizumab) Immunotherapy for Triple Negative Breast Cancer

Keytruda is the name for the immunotherapeutic drug pembrolizumab and was recently approved by the FDA to treat patients of high-risk early-stage triple negative breast cancer. Immunotherapy drugs are those that use the immune system to fight disease.

Adult patient candidates with TNBC for this immunotherapy include patients that the TNBC has returned or spread and that have tumors testing positive for PD-L1 pathway. Early stage TNBC candidates are those that have tumors of 1 to 2 cm and spreading to the lymph nodes or tumors sized greater than 2 cm. TNBC is a hard to treat form of breast cancer with no estrogen or progesterone receptors and that do not make HER2 protein – all receptors normally found in breast cancer (thus the name, triple negative). TNBC doesn’t respond to hormonal therapy.

For TNBC patients, pembrolizumab works with chemotherapy to attack the cancer tumor. Pembrolizumab works as a neoadjuvant immunotherapy to help stop the growth of the tumor or reduce the tumor size before the chemotherapy is administered.

This drug used for TNBC is administered intravenously at the dosage 200 mg every 3 weeks or 400 mg every 6 weeks. Read the “highlights of prescribing information” for the Keytruda (pembrolizumab) intravenous injection, and learn the indications/contraindications for this drug, which can be found in the FDA drug database.

There were serious side effects and adverse reactions to Keytruda in combination with chemotherapy during the KEYNOTE-522 study. During the study, 20% of patients discontinued use due to reactions and .9% of patients died during the study. 44% of patients experienced serious reactions, and 57% of patients had adverse reactions that interrupted administration of the drug. Serious adverse reactions include febrile neutropenia (fever during significant neutropenia), fever, anemia, and neutropenia (low white blood cells). Some adverse reactions leading to permanent discontinuation of the drug were increased ALT or AST (indication of liver damage). Other adverse reactions include neutropenia, thrombocytopenia (low blood platelets), rash, leucopenia (low white cell count), upper respiratory tract infection, and fatigue. General adverse reactions include fatigue, fever, nausea, constipation/diarrhea, alopecia, rash, headache, cough, insomnia, and decreased appetite.

Before you take in all the side effects, of which there are many, realize any chemotherapy or immunotherapy that fights breast cancer will also have many side effects, and it is exciting to learn about a new way to fight TNBC.

For more information on Keytruda brand pembrolizumab, visit “pembrolizumab for high-risk early-stage triple-negative breast cancer” announcement from the FDA.gov. Or, visit directly the study results page from Keytruda about the clinical trial using the drug with chemotherapy.

Image by Becca Tapert from Unsplash.