Case report of entrectinib associated fulminant myocarditis.

Background: ROS1 tyrosine kinase inhibitors are one of the primary immunotherapies for ROS1 fusion-positive cancers. Tyrosine kinase inhibitors have markedly improved outcomes for advanced cancers previously with poor prognosis. Entrectinib is an example of an ROS1 inhibitor that can be used for lung adenocarcinoma. There are numerous adverse effects with rare cardiac side effects reported, such as heart failure and myocarditis.

Case summary: A 27-year-old male being treated for lung adenocarcinoma who presented new congestive heart failure 2 weeks after starting Entrectinib. He developed refractory ventricular tachycardia, cardiogenic shock with an endomyocardial biopsy that showed active lymphohistiocytic myocarditis. With antiarrhythmic therapy, heavy sedation, mechanical circulatory support, and high-dose steroids, the patient had complete resolution of symptoms and return to baseline status.

Discussion: This is a rare case with a severe complication after starting Entrectinib for lung adenocarcinoma. In the literature, this is the first case of its kind presenting with myocarditis and severe heart failure after treatment with Entrectinib. This case highlights not only using cardiac imaging, and biopsy to help guide the diagnosis, but also describe the appropriate management.