HER2CLIMB Shows Efficacy for Brain Metastases in HER2+ Breast Cancer

William J. Gradishar, MD, chief of hematology and oncology, department of medicine, Betsy Bramsen Professorship of Breast Oncology, professor of medicine (hematology and oncology), Northwestern University's Feinberg School of Medicine, discussed the effect tucatinib (Tukysa) had on central nervous system (CNS) metastases in patients with HER2-positive breast cancer.

The HER2CLIMB trial investigated the combination of trastuzumab (Herceptin), tucatinib (Tukysa), and capecitabine versus capecitabine and trastuzumab. The triplet proved to be more effective with respect to progression-free survival (PFS) and overall survival (OS), according to Gradishar. The inclusion criteria allowed patients that had progressive brain metastases not requiring immediate therapy as well as those without brain metastases. The number of patients with brain metastases in the HER2CLIMB trial was significantly greater than what was seen in the DESTINY trial.

Gradishar says it was a much more robust data set to comment on CNS activity of tucatinib. The data looking specifically at the CNS disease demonstrated that the CNS PFS and CNS OS in patients receiving tucatinib was markedly improved compared with those that were only getting capecitabine and trastuzumab. There was evidence that there was a treatment effect in the brain, as well as stabilization. Many people have made the comment that this is a breakthrough with respect to treating HER2-positive CNS disease, which is a significant problem for that population of patients with breast cancer, he explains.