Seattle Genetics Inc. said its tucatinib combination therapy was better than single therapies in treating certain patients with breast cancer, results of a mid-stage study showed.
Data from the phase 2 study, dubbed Her2climb, showed tucatinib in combination with trastuzumab and capecitabine was better than trastuzumab and capecitabine alone in treating patients with HER2-positive breast cancer whose disease has spread to nearby tissue or lymph nodes, cannot be surgically removed or has spread to other parts of the body.
Patients in the clinical trial also previously received trastuzumab, pertuzumab and ado-trastuzumab emtansine, and 47% of them had cancer cells that spread to the brain upon enrollment.
Trastuzumab is sold by Roche Holding AG as Herceptin, while pertuzumab is marketed by the company as Perjeta.
According to the results, the study met its main goal of progression-free survival, or the length of time during and after treatment that a patient lives with the disease but it does not get worse. There was a 46% reduction in the risk of disease worsening or death, showing that the addition of tucatinib was better than having trastuzumab and capecitabine alone.
The trial also met two of its secondary goals, with patients who had tucatinib extending overall survival and those with brain metastases demonstrating better progression-free survival.
Tucatinib in combination with trastuzumab and capecitabine was generally well received with a manageable safety profile, the Bothell, Wash.-based biotechnology company Seattle Genetics said. The most frequent adverse events were diarrhea, hand-foot syndrome, nausea, fatigue and vomiting.
In line with the Her2climb results, Seattle Genetics plans to submit a new drug application to the U.S. Food and Drug Administration in the first quarter of 2020, Chief Medical Officer Roger Dansey said.
The company said it will present additional findings from the study at the 2019 San Antonio Breast Cancer Symposium on Dec. 11.
Tucatinib is also being evaluated in a phase 3 study in breast cancer, as well as in a mid-stage study assessing certain colorectal cancer patients.