Enhertu (Fam-trastuzumab deruxtecan-nxki) for Breast Cancer

Overview
Enhertu is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat adults with HER2-positive breast cancer that is either unresectable (cannot be removed with surgery) or metastatic (has spread to other parts of the body). It is prescribed for people who have already received an anti-HER2 treatment, either for metastatic cancer or as part of neoadjuvant (before surgery) or adjuvant (after surgery) therapy but experienced cancer recurrence during or within six months of completing treatment. Enhertu is also known by its drug name, fam-trastuzumab deruxtecan-nxki.

Enhertu is a targeted therapy that combines a HER2-directed antibody with a topoisomerase inhibitor. It is believed to work by binding to HER2-positive cancer cells, delivering a chemotherapy agent directly inside the cells to trigger cell death.

How do I take it?
Prescribing information states that Enhertu is administered as an intravenous infusion by a health care professional. The recommended dosing schedule is once every three weeks (21-day cycle) until disease progression or unacceptable toxicity. Enhertu should be given exactly as prescribed by a healthcare provider.

Side effects
Common side effects of Enhertu for treating types of breast cancer include decreased white blood cell count, nausea, decreased hemoglobin (low red blood cell count), decreased neutrophil count (a type of white blood cell that fights infection), decreased lymphocyte count (another type of white blood cell), fatigue, decreased platelet count (cells that help blood clot), increased liver enzymes (which may indicate liver irritation), vomiting, hair loss, constipation, decreased blood potassium, and increased blood alkaline phosphatase (a possible sign of liver or bone changes).

Rare but serious side effects may include interstitial lung disease (lung inflammation that can cause breathing problems), severe neutropenia (dangerously low white blood cell count), heart failure (weakened heart function), and embryo-fetal toxicity (potential harm to an unborn baby). Individuals taking this medication report any respiratory symptoms, signs of infection, or unusual fatigue to their doctor immediately.

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Highlights of Prescribing Information: Enhertu (Fam-Trastuzumab Deruxtecan-Nxki) for Injection, for Intravenous Use — Daiichi Sankyo