Targeting ALK With Crizotinib in Pediatric Anaplastic Large Cell Lymphoma and Inflammatory Myofibroblastic Tumor: A Children’s Oncology Group Study

/dose) was 86%. A complete response was observed in 83% (five of six) of ALCL165, 80% (16 of 20) of ALCL280, and 36% (five of 14) of patients with IMT. Partial response rates were 0% (none of six), 10% (two of 20), and 50% (seven of 14), respectively. The median duration of therapy was 2.79, 0.4, and 1.63 years, respectively, with 12 patients ceasing protocol therapy to proceed to transplantation. The most common drug-related adverse event was decrease in neutrophil count in 33% and 70% of the ALCL165 and ALCL280 groups, respectively, and in 43% of patients with IMT. Levels of NPM-ALK decreased during therapy in most patients with ALCL. Conclusion The robust and sustained clinical responses to crizotinib therapy in patients with relapsed ALCL and metastatic or unresectable IMT highlight the importance of the ALK pathway in these diseases.