In a recent conversation with CancerNetwork®, Sara A. Hurvitz, MD, FACP, senior vice president and director of the Clinical Research Division at Fred Hutch Cancer Center and head of the Division of Hematology and Oncology at the University of Washington Department of Medicine, discussed new treatment options for patients with metastatic HER2-positive breast cancer. 

In the discussion, Hurvitz highlighted findings from the phase 3 HER2CLIMB-02 trial (NCT03975647), which assessed the efficacy and safety of tucatinib (Tukysa) plus ado-trastuzumab emtansine (Kadcyla; T-DM1) in patients with HER2-positive breast cancer, specifically those with brain metastases. 

Patients enrolled in this trial experienced a significant improvement in progression-free survival (PFS) with the tucatinib-based regimen. Data presented at the 2023 San Antonio Breast Cancer Symposium (SABCS) highlighted that the median time to disease progression or death was 9.5 months (95% CI, 7.4-10.9) and 7.4 months (95% CI, 5.6-8.1 in the experimental arm and placebo arm, respectively (HR, 0.76; 95% CI, 0.61-0.95; P = .0163). In patients with brain metastases, the median time to disease progression or death was 7.8 months (95% CI, 6.7-10.0) and 5.7 months (95% CI, 4.6-7.5) in the experimental arm and placebo arm, respectively (HR, 0.64; 95% CI, 0.46-0.89). Investigators reported that toxicity in the experimental arm was generally manageable and reversible.

“This was a study that only enrolled patients who were naive to trastuzumab deruxtecan [T-DXd; Enhertu],” Huvitz said. “We know that T-DXd has substantial improvements in PFS and survival, so having so many patients receive this [agent] after progression is certainly going to impact our ability to observe survival differences. About 15% of patients in each arm also went on to receive tucatinib. These are pretty exciting results for our patients, especially those with brain metastases. This study did enroll, as I said, patients with brain metastases, who comprised 44% or so of the entire population enrolled in this study. These are interesting data, and we'll see if this regimen is ultimately approved.”

Hurvitz SA, Loi S, O’Shaughnessy J, et al. HER2CLIMB-02: randomized, double-blind phase 3 trial of tucatinib and trastuzumab emtansine for previously treated HER2-positive metastatic breast cancer. Presented at the 2023 San Antonio Breast Cancer Symposium; December 5-9, 2023; San Antonio, TX. Session GS01-10.