Crizotinib Efficacy After Progression With Entrectinib in ROS1-Positive Lung Cancer: A Case Report

Crizotinib and entrectinib are approved tyrosine kinase inhibitors by the FDA to treat advanced-stage ROS1-positive non-small cell lung cancer (NSCLC). Although, entrectinib could be used after crizotinib, it is unknown whether crizotinib is effective after entrectinib. We report a case of NSCLC with ROS1 rearrangement that achieved a nearly complete response with crizotinib in the second-line treatment after progression with entrectinib. A 22-year-old Caucasian non-smoker female patient was diagnosed with stage IV non-squamous lung cancer with ROS1 positivity. We started on entrectinib as first-line therapy. Due to progression in the 10th month of treatment, entrectinib was stopped and crizotinib was started as a second -line treatment. At the end of the third month of the treatment, a nearly complete response was obtained in the follow-up imaging. The patient is still being followed up with crizotinib and is in the 15th month of treatment. Based on our experience, crizotinib can be an option as second-line therapy in patients who are treated with entrectinib in the first line, especially in patients without brain metastasis.