Taletrectinib in Previously Treated Metastatic CDH1-mutated Invasive Lobular Cancer (ILC)

Invasive lobular cancer (ILC) represents 10-15% of all breast cancers, up to 75% of ILCs carry a mutation in CDH1 gene which encodes for e-cadherin (ECAD), which is a cell adhesion glycoprotein. Preclinical data using patient derived xenografts have shown loss of ECAD due to CDH1 mutation is associated with an upregulation ROS1 activity, and ROS1 inhibitors have demonstrated synthetic lethality in CDH1-mutated cell lines. Taletrectinib is a novel ROS1/NTRK inhibitor with demonstrated activity in ROS1 mutated non-small cell lung cancer. The purpose of the trial is to estimate the activity of taletrectinib in previously treated CDH1-mutated metastatic breast ILC.