A breakthrough study presented at the San Antonio Breast Cancer Symposium 2023 highlights the significant advancements in managing HER2-positive metastatic breast cancer. Combining Tukysa (tucatinib) with Kadcyla (ado-trastuzumab emtansine) has shown promising outcomes, especially in extending progression-free survival for patients, even those with brain metastasis.
Tukysa, an oral tyrosine kinase inhibitor, approved in 2020, and Kadcyla, utilizing HER-targeted antibodies, function synergistically, impeding HER2 receptors, which play a pivotal role in promoting cell growth. Notably, Tukysa’s distinctive attribute lies in its ability to combat brain cancer, setting it apart from conventional HER2-targeted drugs.
Dr. Sara Hurvitz from the University of Washington and Fred Hutchinson Cancer Center highlighted the dire need for effective treatments against breast cancer brain metastases, an area with limited therapeutic options. The HER2CLIMB-02 trial enrolled 463 patients, a significant proportion having brain metastasis at baseline. Administering Tukysa tablets alongside Kadcyla infusions resulted in a 24% reduced risk of disease progression or death compared to the placebo group. Among those with brain metastasis, Tukysa demonstrated a remarkable 36% reduction in disease progression.
Though generally well-tolerated, patients on the Tukysa regimen reported more adverse events, notably liver enzyme elevations, anemia, low platelets, and fatigue. However, Dr. Hurvitz emphasized the manageable nature of these side effects through careful monitoring and clinical intervention.
The study’s findings pose questions about current brain metastasis monitoring guidelines for advanced breast cancer patients, suggesting a potential reevaluation. Dr. Kate Lathrop from the Mays Cancer Center at UT Health stressed the challenge in identifying asymptomatic brain metastasis cases that could benefit from Tukysa. Dr. Hurvitz echoed the importance of rethinking brain imaging guidelines, hinting at Tukysa’s potential in delaying the need for brain radiation.
The data, with a median follow-up of about two years, provides promising insights, particularly regarding the potential role of Tukysa in managing brain metastasis, offering renewed hope for patients with HER2-positive metastatic breast cancer.