Drastic initial response and subsequent response to two ALK inhibitors in a patient with a highly aggressive ALK-rearranged inflammatory myofibroblastic tumor arising in the pleural cavity.

A 57-year-old male current smoker was diagnosed with an aggressive variant of ALK-rearranged inflammatory myofibroblastic tumor (IMT) arising in the pleural cavity. First line treatment with ASP3026 was initiated at a dose of 125mg once daily. A follow-up CT scan revealed drastic regression of the pleural lesion. After disease progression with ASP3026 treatment, LDK378 (ceritinib) was initiated at a dose of 750mg once daily. A follow-up CT scan revealed a second drastic regression of the pleural lesion. Furthermore, it is noteworthy that this case represents the use of serum hyaluronan levels to assist in monitoring of treatment efficacy in an IMT. Herein, we present the first case of a patient with a highly aggressive ALK-rearranged IMT arising in the pleural cavity, who showed both initial and subsequent drastic response to two ALK inhibitors while being monitored for serum hyaluronan.