Pfizer announced successful Phase III HER2CLIMB-05 trial results, showing oral HER2 tyrosine kinase inhibitor (TKI) tucatinib combined with trastuzumab and pertuzumab significantly improved progression-free survival (PFS) versus placebo plus dual HER2 blockade as maintenance therapy following induction treatment in 654 patients with HER2-positive metastatic breast cancer. The study met its primary endpoint with statistically significant and clinically meaningful PFS benefit while maintaining a tolerable safety profile consistent with that of individual agents. Tucatinib gained US market approval in April 2020 for previously treated HER2-positive metastatic breast cancer, including brain metastases, and expanded to colorectal cancer in January 2023.

The trial addresses an unmet need in the first-line maintenance setting, where standard of care has remained unchanged since 2012 despite approximately 50% of HER2-positive metastatic breast cancer patients experiencing disease progression within two years. HER2 overexpression occurs in 15% to 20% of breast cancers associated with poorer prognosis and has 41% to 47% five-year survival rates depending on hormone receptor (HR) status. The positive results position tucatinib as a potential new option for sustained disease control following initial induction therapy in this aggressive breast cancer subtype.

PharmCube's NextBiopharm® database lists 20 HER2 TKIs approved in breast cancer, with nearly a hundred undergoing clinical trials. Click here to request a free trial for NextBiopharm®.