The pivotal HER2CLIMB trial showed that the addition of tucatinib (Tukysa) to trastuzumab (Herceptin) and capecitabine (Xeloda) resulted in clinically meaningful improvements in overall survival (OS), progression-free survival (PFS) and objective response rate (ORR) compared with the addition of placebo. A new exploratory analysis presented at the virtual San Antonio Breast Cancer Symposium demonstrated that the PFS, OS, and ORR improvements with tucatinib were observed consistently across hormone receptor status subgroups, including in patients with brain metastases.
In this exclusive MedPage Today video, study author Erika P. Hamilton, MD, director of the Breast Cancer and Gynecologic Cancer Research Program at Sarah Cannon Research Institute in Nashville, discusses the findings.
Following is a transcript of her remarks:
I want to give you an update on HER2CLIMB hormone receptor status that was presented at San Antonio Breast. We’re all familiar with the initial HER2CLIMB data that was presented, showing an improvement in progression-free survival response rate, overall survival, as well as progression-free survival and overall survival in the subset of patients that had brain metastasis.
Based on the initial data for HER2CLIMB, tucatinib was approved in early 2020 for patients with and without brain metastases that had received at least one line in the metastatic setting of treatment. Again, in this analysis, we looked at the benefit of tucatinib in addition to capecitabine and trastuzumab backbone, for patients that were either hormone receptor positive or hormone receptor negative. So really looking to see whether the benefit was across the board.
So numerically, there was a benefit for both hormone receptor positive patients and hormone receptor negative patients across all five end points: progression-free survival, overall survival response rate, and progression-free survival in brain metastasis and overall survival in brain metastasis.
All of these were statistically significant for those patients with hormone receptor negative disease, and some of them favored numerically, but were not statistically significant for hormone receptor positive disease. Specifically, progression-free survival improved in hormone receptor positive disease from 5.6 up to 7.6 months, and progression-free survival and brain metastases for hormone receptor positive — 5.1 up to 7.5 months.
These were significant. However, overall survival did not meet statistical significance.
Really to me, this suggests that tucatinib is active in HER2-positive disease with brain mets, without brain mets, and regardless of hormone receptor status.
So to me, this is a standard regimen post-pertuzumab, post TDM-1, and certainly to be considered in all patients with brain metastases — possibly even earlier.