By: IPP Bureau
Last updated : December 12, 2025 11:37 am
The Phase 3 HER2CLIMB-05 trial showed a 35.9% reduction in risk for patients treated with TUKYSA
Global pharma powerhouse Pfizer has announced that its HER2-targeted drug TUKYSA (tucatinib) significantly reduced the risk of disease progression or death in patients with HER2-positive metastatic breast cancer (MBC) when used as part of a first-line maintenance therapy following chemotherapy.
The Phase 3 HER2CLIMB-05 trial showed a 35.9% reduction in risk for patients treated with TUKYSA, trastuzumab, and pertuzumab compared to placebo plus trastuzumab and pertuzumab (hazard ratio 0.641; 95% CI: 0.514-0.799; p<0.0001). Results were published today in the Journal of Clinical Oncology and presented at the 48th San Antonio Breast Cancer Symposium (SABCS).
Median progression-free survival (PFS) was 24.9 months for patients receiving TUKYSA versus 16.3 months for those on placebo—a gain of 8.6 months. Benefits were seen across all patient subgroups, including de novo or recurrent disease, hormone receptor-positive or -negative tumors, and in patients with or without brain metastases. Overall survival data are not yet mature but showed a favorable trend for TUKYSA.
'Most patients with HER2-positive metastatic breast cancer face disease progression within two years of starting first-line treatment, often requiring a transition to chemotherapy,” said Erika Hamilton, principal investigator of HER2CLIMB-05 and Director of Breast Cancer Research for Sarah Cannon Research Institute.
“These results demonstrate that adding tucatinib to first-line maintenance therapy extends the time patients live without their disease progressing, while maintaining a manageable safety profile, suggesting a promising new potential approach that could advance the current standard of care for HER2-positive disease.”
TUKYSA’s safety profile in combination with trastuzumab and pertuzumab was generally consistent with known effects of each drug, with the exception of higher rates of asymptomatic Grade ≥3 liver enzyme elevations. These were manageable and reversible with dose adjustments. The most common side effects were diarrhea, liver events, and nausea.
“TUKYSA has become a trusted standard of care for patients with later-line HER2-positive metastatic breast cancer, and the results from HER2CLIMB-05 support its potential use as part of a chemotherapy-free, front-line maintenance strategy,” said Jeff Legos, Chief Oncology Officer, Pfizer.
“At Pfizer, we are committed to advancing treatment options that meaningfully improve the lives of people with metastatic breast cancer, and we are proud to share these promising results for patients and their families.”