New Drug Combo for Aggressive Breast Cancer

Medically Reviewed by Poonam Sachdev on October 12, 2021

Enhertu may offer good news for women with HER2-positive breast cancer, an aggressive form of the disease. This new drug combo treatment prevents cancer from growing three times longer than the standard treatment, trastuzumab emtansine (T-DM1). 

Enhertu has been approved by the FDA to treat HER2-positive breast cancer that is unresectable, which means it can't be treated with surgery. It is also approved to treat metastatic breast cancer that has already been treated with two or more anti-HER2 therapies. Metastatic means cancer has spread to other parts of the body.   

HER2-positive breast cancer is an aggressive type of breast cancer that makes too many copies of a gene called HER2. This gene makes a protein that is a HER2 receptor. These receptors cause the cell to grow and multiply. 

Enhertu therapy is a combination treatment that consists of three parts: 

  1. Fam-trastuzumab, which is an anti-HER2 medicine that is basically the same structure as trastuzumab
  2. Topoisomerase I inhibitor chemotherapy called DXd, which interferes with cancer cells' ability to reproduce
  3. A substance that links the molecules of fam-trastuzumab and topoisomerase I inhibitor chemotherapy

Of the women who received Enhertu, 60.9% responded to Enhertu. 6% had a complete response (no evidence of cancer), and 54.9% had a partial response, where cancerous tumors stopped growing or got smaller. The median progression-free survival was 16.4 months, with some living longer progression-free, and some living for a shorter time progression-free. 

The side effects of Enhertu may include: 

  • Nausea and vomiting
  • Tiredness
  • Constipation
  • Hair loss
  • Diarrhea
  • Cough
  • Decreased appetite
  • Anemia
  • Low white blood cell count

Serious side effects are not as common but can include scarring and inflammation in the lungs, and heart problems. Tell your doctor immediately if you have any of the following symptoms: 

  • Shortness of breath
  • Dry cough
  • Swelling in your ankles or legs
  • Weight gain of more than 5 pounds in 24 hours
WebMD Medical Reference


SOURCES: "Enhertu," "FDA Approves Enhertu for Unresectable or Pretreated Metastatic HER2-Positive Breast Cancer."

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