Phase Ib Trial of Fulvestrant, Palbociclib, and Erdafitinib, a pan-FGFR Tyrosine Kinase Inhibitor, in HR+/HER2− Metastatic Breast Cancer

The trial endpoint was met establishing the MTD of erdafitinib at 6 mg. Whereas the triplet regimen may pose tolerability challenges, alterative doublets with selective FGFR1 inhibitors in patients with FGFR1-dependent tumors, possibly administered in sequence, are worthy of further investigation.