Dr. O’Shaughnessy on the Utility of Tucatinib in the HER2+ Breast Cancer Brain Metastases

Joyce A. O'Shaughnessy, MD, chair of Breast Cancer Research and chair of Breast Cancer Prevention Research at Baylor-Sammons Cancer Center of Texas Oncology, as well as the 2016 Giant of Cancer Care^® in Community Outreach, discusses the utility of tucatinib (Tukysa) in HER2-positive breast cancer with brain metastases.

An update on the phase 2 HER2CLIMB trial was presented during the 2020 ASCO Virtual Scientific Program. In this trial, the selective HER2-targeted TKI tucatinib was added to capecitabine plus trastuzumab (Herceptin) versus capecitabine, trastuzumab, and placebo, says O’Shaughnessy. The update focused specifically on patients who had brain metastases. A total of 174 patients had active brain metastases that were either untreated or treated and progressing.

Results showed that the addition of tucatinib improved progression-free survival (PFS) in the brain metastases themselves, says O'Shaughnessy. Tucatinib not only improved overall PFS, including all of the systemic, metastatic disease, but also substantially reduced progression in the central nervous system; the agent showed powerful penetration and activity in the brain, adds O'Shaughnessy. Importantly, tucatinib also improved the survival of patients with brain metastases compared with those who did not receive the TKI.

These data cemented the importance of tucatinib for use in patients with HER2-positive metastatic breast cancer who have brain metastases, even if they are progressing and active or they have not been treated previously. This allows patients to be spared from radiation therapy for a while, concludes O’Shaughnessy.