As part of Project Orbis, the U.S. Food and Drug Administration approved Tukysa (tucatinib) in combination with chemotherapy (trastuzumab and capecitabine) for the treatment of adult patients with advanced forms of HER2-positive breast cancer that can’t be removed with surgery, or has spread to other parts of the body, including the brain, and who have received one or more prior treatments.
“This approval represents an additional targeted treatment option for patients with HER2-positive breast cancer. The clinical trial supporting this approval enrolled and specifically studied patients with active brain metastases in addition to the overall population enrolled, which also demonstrated benefit in this subgroup” said Richard Pazdur, M.D., director of the FDA’s Oncology Center of Excellence.
The median PFS in patients who received Tukysa, trastuzumab, and capecitabine was 7.8 months compared to 5.6 months in those patients who received placebo, trastuzumab, and capecitabine. Overall survival and PFS in patients with brain metastases at baseline were key secondary endpoints. The median overall survival in patients who received Tukysa, trastuzumab, and capecitabine was 21.9 months compared to 17.4 months in patients who received placebo, trastuzumab, and capecitabine. The median PFS in patients with brain metastases at baseline who received Tukysa, trastuzumab and capecitabine was 7.6 months compared to 5.4 months in patients who received placebo, trastuzumab and capecitabine.
HER2-positive breast cancer, which makes up approximately one-fifth of breast cancers, has too much of a protein called human epidermal growth factor receptor 2 (HER2), which promotes the growth of cancer cells. More than 25% of women with metastatic HER2-positive breast cancer will develop brain metastases.