Dr. Hamilton on the FDA Approval of Tucatinib in HER2+ Breast Cancer

Erika P. Hamilton, MD, director of the Breast Cancer and Gynecologic Research Program and principal investigator at Sarah Cannon Research Institute, discusses the FDA approval of tucatinib (Tukysa) in HER2-positive breast cancer.

On April 17, 2020, the FDA approved the combination of tucatinib, trastuzumab (Herceptin), and capecitabine (Xeloda) for the treatment of patients with unresectable locally advanced or metastatic HER2-positive breast cancer, including patients with brain metastases, following at least 1 prior therapy.

The approval is based on data from the phase II HER2CLIMB trial which showed a 34% reduction in the risk of death with the triplet versus trastuzumab/capecitabine alone in heavily pretreated patients. The median overall survival was 21.9 months and 17.4 months with the triplet and doublet, respectively (HR, 0.66; 95% CI, 0.50-0.88; P = .0048). Moreover, overall response rate and progression-free survival in the overall population and in patients with brain metastases at baseline favored the use of tucatinib.

Notably, 48% and 46% of patients had metastases at baseline in the triplet and doublet arms, respectively, representing a high-risk population, says Hamilton. The study is the first randomized trial in HER2-positive metastatic breast cancer to include patients with untreated or previously treated, progressive brain metastases. The regimen is going to be an important addition to the armamentarium for patients with or without brain metastases, concludes Hamilton.