Larotrectinib for Newly Diagnosed Infantile Fibrosarcoma and Other Pediatric NTRK Fusion–Positive Solid Tumors
In this study, called ADVL1823, larotrectinib was administered to patients with newly diagnosed tumors. Of the 33 total patients, 18 had infantile fibrosarcoma (IFS), which is a malignant fibroblastic tumor in infants, marked by rapid growth and local aggression, with rare metastasis, often featuring a fusion of the proteins ETV6 and NTRK3. Another 15 patients had other solid tumors, including other sarcoma types. The objective response rate (ORR) within six cycles was 94% and 60% in patients with IFS and other solid tumors respectively. Two-year event-free survival (EFS) and overall survival (OS) were 82.2% and 93.8% for IFS and 80% and 93.3% for other solid tumors. Patients undergoing surgical resection of their tumor had prolonged EFS, with only 1 of 16 such patients experiencing disease progression.
These results indicate that larotrectinib is highly effective in patients with newly diagnosed NTRK fusion–positive solid tumors including IFS and should be considered for frontline therapy.