HGG-52. SUSTAINED RESPONSE TO CRIZOTINIB MONOTHERAPY IN AN INFANT WITH GOPC-ROS1 FUSED CONGENITAL HEMISPHERIC GLIOMA

Abstract Recent studies identified the presence of ALK/ROS/NTRK/MET alterations in a subset of infantile hemispheric gliomas. We report a case of GOPC-ROS1 fused congenital hemispheric glioma with a sustained response to crizotinib. An infant born at 28 weeks gestation was diagnosed with a large hemispheric mass at 2 weeks of life. The tumor was partially resected at 7 weeks of life. Histological evaluation confirmed a neoplasm with a spindle cell growth pattern, hypercellularity, nuclear pleomorphism, endothelial proliferation and necrosis consistent with glioblastoma. Fresh tissue was submitted for targeted panel sequencing (Oncopanel) which identified the presence of a GOPC-ROS1 fusion (exon 36:intron 4). This was confirmed by copy number analysis which showed a focal intragenic deletion with a breakpoint in ROS1 on 6q22. Given the lack of preclinical native models for ROS1 and other congenital kinase-driven gliomas, live cells were utilized to attempt to establish a patient derived cell line (organoid/neurosphere model) and intracranial patient derived xenograft model, the results of which are pending and will be reported. The GOPC-ROS1 rearrangement was structurally predicted to respond to kinase inhibitors with activity against ROS1 and crizotinib was started at 280 mg/m2/dose twice daily at 6 months of life with progressive tumor noted on imaging. Three months after initiating therapy, a 56% reduction in the tumor size and subsequent imaging revealed additional response. Our report is the first to demonstrate clinical response to crizotinib in a GPOC-ROS1 fused congenital glioblastoma and describe the development of a renewable resources for future analysis.