Dr. Lin on Updated Findings of HER2CLIMB Study in HER2+ Breast Cancer Brain Mets

Nancy U. Lin, MD, associate professor of medicine at Harvard Medical School; associate chief of the Division of Breast Oncology, Susan F. Smith Center for Women’s Cancers; director of the Metastatic Breast Cancer Program and senior physician at Dana-Farber Cancer Institute, discusses updated findings from the phase 2 HER2CLIMB study in patients with HER2-positive metastatic breast cancer with brain metastases.

In the trial, patients were randomized to receive either tucatinib (Tukysa) or placebo, in combination with trastuzumab (Herceptin) and capecitabine. Investigators looked at the overall population of patients with brain metastases but also provided additional granular details on how patients in the various brain metastases subgroups faired on the treatment, says Lin. Investigators examined how patients with newly diagnosed brain metastases did on the trial. They also shed light on how patients who had active or progressive brain metastases going into the trial did on the HER2CLIMB regimen.

In patients with brain metastases, the PFS rate by blinded independent central review at 1 year was 25.9% with the tucatinib combination versus 0% with the placebo combination, which led to a 52% reduction in the risk of progression or death in these patients. The median PFS in this patient population was 7.6 months in those treated with tucatinib and 5.4 months in those who received placebo.

Another interesting aspect of this research, which was unique to HER2CLIMB, is that patients who developed isolated central nervous system (CNS) progression, when they were on the randomized trial therapy, were not immediately taken off of protocol, says Liu. These patients were allowed to stay on the study, receive stereotactic radiation or localized CNS-directed therapy, and remain on the randomized blinded arm. Investigators also presented data comparing the 2 arms as far as how long patients were able to continue on their treatment until time of next progression, concludes Lin.