FIG 2.

Extracranial response to larotrectinib in a patient with TRK fusion-positive lung cancer. (A) Baseline computed tomography imaging of the chest revealed innumerable bilateral pulmonary metastases that resulted in substantial dyspnea. Treatment with larotrectinib achieved a brisk clinical response within the first 2 weeks as evidenced by decreased shortness of breath. This was accompanied by a radiologic partial response to therapy that (B) was observed at 8 weeks and (C) was confirmed at 16 weeks. Previously solid and semisolid confluent nodules regressed substantially.