Adding Tukysa (tucatinib), a tyrosine kinase inhibitor, to Kadcyla (ado-trastuzumab emtansine), an antibody-drug conjugate, improved progression-free survival (PFS) for patients with advanced HER2-positive breast cancer, including those with brain metastasis, according to study findings presented at the San Antonio Breast Cancer Symposium.


The Phase III HER2CLIMB-02 trial enrolled 463 people with inoperable locally advanced or metastatic breast cancer. They were randomly assigned to receive Tukysa or a placebo along with Kadcyla. The median PFS time was 9.5 months in the Tukysa group versus 7.4 months in the placebo group—a 24% reduction in the risk of disease progression or death. Among patients with brain metastasis, the median PFS time was 7.8 months versus 5.7 months. Median overall survival was 53 months in the placebo group and not yet reached in the Tukysa group. Sara Hurvitz, MD, of Fred Hutchinson Cancer Center, suggested that monitoring for brain metastasis may be warranted to identify patients who might benefit from this treatment.