Pfizer's TUKYSA Combination Improves Progression-Free Survival in Breast Cancer Trial

NEW YORK – Pfizer Inc. has announced positive top-line results from the Phase 3 HER2CLIMB-05 trial evaluating the tyrosine kinase inhibitor TUKYSA® (tucatinib) in combination therapy for patients with HER2-positive (HER2+) metastatic breast cancer (MBC) as a first-line treatment.

The trial met its primary endpoint, demonstrating a statistically significant and clinically meaningful improvement in progression-free survival (PFS) by investigator assessment in the TUKYSA arm compared to the placebo arm. The study evaluated TUKYSA versus placebo, both in combination with first-line standard-of-care maintenance therapy (trastuzumab plus pertuzumab) following chemotherapy-based induction.

"HER2+ breast cancer is a particularly challenging subtype, with many patients experiencing disease progression despite effective treatments in the first-line setting," said Erika Hamilton, M.D., principal investigator of HER2CLIMB-05. "The HER2CLIMB-05 results demonstrate that the addition of TUKYSA to first-line maintenance therapy may further lower the risk of disease progression or death, with a treatment that has a well-established safety profile."

Treatment with TUKYSA in combination with trastuzumab and pertuzumab was tolerable, with a safety profile generally consistent with the established safety profiles of each individual therapy. Results from HER2CLIMB-05 will be presented at a future medical congress and discussed with regulatory authorities.

TUKYSA is currently approved for third-line treatment in HER2+ MBC, including patients with brain metastases who have received one or more prior anti-HER2-based regimens in the metastatic setting. Pfizer is exploring TUKYSA's potential to shape first-line treatment for HER2+ MBC.