The FDA has approved it for two uses in adults with HER2-positive early-stage breast cancer.
It can now be used before surgery (neoadjuvant care) along with other cancer treatments (a taxane plus trastuzumab and pertuzumab therapy often called THP) for patients with stage II or III HER2-positive breast cancer.
It is also approved for use after surgery (adjuvant therapy) in patients who still have invasive cancer despite prior treatment with trastuzumab (with or without pertuzumab) and taxane-based therapies.
The FDA also cleared two lab tests – the PATHWAY anti‑HER‑2/neu (4B5) IHC and the VENTANA HER2 Dual ISH DNA Probe Cocktail – to help identify eligible patients. Breast cancer remains one of the leading causes of cancer deaths worldwide, with more than 320,000 cases diagnosed each year. HER2 is a protein found on the surface of many cancer cells, promoting their growth and survival. Enhanced expression of the HER2 gene leads to overproduction of the HER2 protein, which is often linked to more aggressive breast cancer and poor outcomes. About 1 in 5 breast cancer cases are HER2-positive, and many patients face a higher risk of the disease returning even after treatment (recurrence).
Why Was It Approved?
The FDA’s approval is based on results from two clinical studies that showed that Enhertu made for significant clinical improvement in both neoadjuvant and adjuvant settings in patients with HER2-positive, high-risk, early-stage breast cancer. The effectiveness of Enhertu followed by THP was studied in a trial involving 927 patients with HER2-positive early-stage breast cancer. Patients were split into three groups to receive eight cycles of pre-surgery or neoadjuvant treatment: one group received four cycles of Enhertu followed by four cycles of THP, another received standard chemotherapy (doxorubicin and cyclophosphamide for four cycles followed by THP), and the third group received investigational therapy for all eight cycles. The main goal was to measure pathologic complete response (pCR), meaning no invasive cancer was found in the breast or lymph nodes after surgery. The pCR rate was 67.3% in the Enhertu-THP group, compared with 56.3% in the standard chemotherapy group, showing a statistically significant improvement.
What Do I Need to Know?
Your health care provider must confirm HER2-positive status to use Enhertu in early breast cancer care. Enhertu is given only by IV infusion. It is not given as a quick IV push or bolus. The first infusion usually takes about 90 minutes. If you tolerate it, later infusions may run about 30 minutes. Before starting and prior to each dose of Enhertu, your health care provider will check your blood counts to watch for neutropenia and platelet levels. They will also assess your heart’s pumping function – left ventricular ejection fraction (LVEF) – at baseline and monitor it during the treatment, if required. Your health care provider will stop Enhertu permanently if you get confirmed lung inflammation that is more than mild, your LVEF values are very low, or if you show symptoms that suggest heart failure. Be sure to let your health care provider know about your medical history. Tell them about all the medicines, including prescription and over-the-counter medicines, vitamins, and herbal supplements, you take.
