Nancy U. Lin, MD, discusses the latest findings from the HER2CLIMB study of either tucatinib or placebo, added to trastuzumab and capecitabine, for patients with previously treated HER2-positive metastatic breast cancer who have brain metastases.
Nancy U. Lin, MD, associate professor of medicine at Harvard Medical School; associate chief of the Division of Breast Oncology at the Susan F. Smith Center for Women's Cancers; and director of the Metastatic Breast Cancer Program at the Dana-Farber Cancer Institute, discusses the latest findings from the HER2CLIMB study (NCT02614794) of either tucatinib (Tukysa) or placebo, added to trastuzumab (Herceptin) and capecitabine (Xeloda), for patients with previously treated HER2-positive metastatic breast cancer who have brain metastases.
The HER2CLIMB trial enrolled about 600 patients, of which 291 patients had brain metastases at baseline, which Lin says is a unique feature of this clinical trial. Of the 291 patients, 60% had new or active brain metastases when entering the study. She and the other investigators were looking at outcomes of patients with brain metastases enrolled on HER2CLIMB.
With the tucatinib regimen, the investigators found the intracranial response rate was higher. About half of patients on the triplet achieved a central nervous system (CNS) partial response or better compared with about 20% who received the placebo regimen. Lin says that more importantly, there was a prolongation of the CNS progression-free survival, which was defined as time from randomization to CNS progression or death. CNS progression was reduced by about two-thirds for patients receiving tucatinib, and there was a 5-month absolute improvement in median time to CNS progression or death.
There was a significant improvement in overall survival for the brain metastasis population receiving the triplet regimen. The hazard ratio for survival was 0.58, and there was an absolute improvement of about 6 months for the median overall survival with tucatinib in this difficult-to-treat patient population, according to Lin.