Chemotherapy-Free Triplet Regimen Shows Promise in Pre-Treated HR+/HER2+ Metastatic Breast Cancer

In this phase 2a study of 51 heavily pretreated patients with hormone receptor-positive, HER2-positive metastatic breast cancer, the chemotherapy-free combination of zanidatamab, palbociclib, and fulvestrant achieved a 6-month progression-free survival rate of 66.7%, with manageable safety signals including predominantly low-grade diarrhea and grade 3–4 neutropenia, and no treatment-related deaths.

The encouraging efficacy alongside an acceptable toxicity profile underscores the potential of this novel triplet regimen as a valuable treatment option for heavily pretreated patients, warranting further clinical evaluation.