Updated findings of the phase 2 HER2CLIMB study demonstrated that patients with HER2-positive metastatic breast cancer who developed brain metastases experienced a 52% reduction in the risk of death after receiving the combination of Tukysa (tucatinib), Herceptin (trastuzumab) and capecitabine. These findings were presented that the 2020 American Society of Clinical Oncology (ASCO) Virtual Scientific Program.
In an interview with OncLive®, a sister publication of CURE®, Dr. Nancy U. Lin, director of the Metastatic Breast Cancer Program and senior physician at Dana-Farber Cancer Institute, discussed the findings of this trial but also highlighted the significance of its impact on this patient population. Moreover, she discussed the importance of having patients with HER2-positive metastatic breast cancer who develop brain metastases included in clinical trials.
In the case of HER2-positive metastatic breast cancer, at least half of patients will develop brain metastases over the course of their disease. And so, this is not a rare occurrence, this is a very common occurrence in our patients who have HER2-positive advanced breast cancer. Until now, there have been no drugs with an FDA indication for the systemic treatment of patients with brain metastases.
Although there have been a number of single arm phase two trials, most notably have a number of other HER2 TKI’s such as lapatinib and neratinib, which has shown CNS objective responses. But this is the first randomized trial to demonstrate an overall survival benefit for patients with brain metastases, which I think is very significant.
It’s also significant when we think about how we should consider patients with brain metastases and inclusion in clinical trials. This is as you noted, an unmet medical need, and the only way we can improve how people do is to allow patients with brain metastases in clinical trials, even starting from early phase studies, to understand whether they would be appropriate to include in eventual registration trials. Because again, this is really the only way that we can make progress.
This type of trial design, including patients in the early phase studies, looking for a signal and then depending on that, going ahead and including potentially those patients in larger phase two, and then eventually phase three trials, is something that is endorsed at this point by the ASCO Friends of Cancer Research Eligibility Working Group, among other groups. And in fact, the FDA has been very supportive of inclusion of patients with brain metastases in a thoughtful way in trials.