Abstract 2857: Perspectives from a systematic review of kinase fusion oncogenes and access to corresponding kinase inhibitor clinical trials in pediatric, adolescent, and young adult solid malignancies
Authors: Vega Lorena Lazo de la , Eder Sebastian K. , Sukharevsky Ellen , Kahn Zachary A. , O'Connell Michaela , Wachter Franziska , Anderson Emily P. , Trissal Maria C. , LaBelle Jenna J. , Carpenter Kendall , Kager Leo , Filbin Mariella G. , Janeway Katherine A. 
Published: March 2024

Abstract
Oncogenic kinase fusions (KFs) have been reported in pediatric, adolescent, and young adult (P-AYA) brain tumors, sarcomas, and rare solid malignancies. Molecularly targeted therapy (MTT) matched to KFs generally produce objective responses even in advanced P-AYA malignancies. KFs occur across a broad age range of P-AYA cancer diagnoses (dx) so data on KF prevalence and the relationship between KFs and clinical characteristics including response and resistance to MTT is distributed across many studies. To address resulting knowledge gaps, we conducted a systematic review of KFs reported in P-AYA cancers and assessed the availability of clinical trials (CTs) for P-AYA patients with KF malignancies. A systematic literature search was conducted with PubMed using publication date 2013-2022, search terms for dx, age, and gene names of interest (BRAF, RAF1, NTRK1-3, ALK, FGFR1-4, MET, RET, ROS1). Known P-AYA cancer sequencing studies were also reviewed. Papers were included if they reported ≥1 patient &lt;18 yo with a KF cancer of any type or ≤30 yo with a KF P-AYA cancer dx. Data abstracted included paper type, KF gene and partner, dx, fusion breakpoints, age, stage, MTT received, response to MTT, and CT enrollment. Clinicaltrials.gov was queried for interventional CTs in the U.S. assessing relevant MTTs. We identified 531 studies (299 case reports/series; 119 P-AYA sequencing studies) reporting 4,329 patients with a KF P-AYA solid tumor. Brain tumors had, in decreasing order of frequency, BRAF, NTRK, FGFR, ALK, ROS1, RAF1, MET, and RET fusions. Dx in which KFs were reported were LGG (n=2451), HGG (n=298), embryonal tumors (n=16), ependymomas (n=8), meningioma (n=1), and other (n=16). Extracranial solid tumors (EST) had, in decreasing order of frequency, NTRK, RET, ALK, BRAF, ROS1, MET, FGFR, and RAF1 fusions. Dx in which KFs were reported were thyroid cancer (n=607), sarcoma (n=546), melanoma and spitz tumor (n=183), renal tumor (n=90), carcinoma (n=57), rhabdomyosarcoma (n=12), neuroblastoma (n=11), osteosarcoma (n=9), and other (n=24). As of Aug 23, 2023, 476 CTs were assessing 65 inhibitors relevant for these KFs, of which only 20 are currently FDA-approved. Patients &lt;18 yo were only eligible for 16% of CTs. RET (47%), RAF/BRAF (33%), and NTRK (32%) inhibitors had the highest percent of CTs enrolling patients &lt;18 yo while ERK (4%) and FGFR (6%) inhibitors had the least. Notably, while 467 P-AYA patients identified in our review were &lt;18 yo and had an ALK- or ROS1-fusion positive tumor, only 24% of ALK or ROS1 inhibitor CTs allowed enrollment of patients &lt;18 yo. To our knowledge, this is the first systematic review of KFs in P-AYA solid tumors. Oncogenic KFs are common and occur across P-AYA solid and brain tumor dx demonstrating a need for CTs of relevant MTTs including patients &lt;18 yo, particularly for drugs targeting ALK, ROS1, and FGFR.
Citation Format: Lorena Lazo de la Vega, Sebastian K. Eder, Ellen Sukharevsky, Zachary A. Kahn, Michaela O'Connell, Franziska Wachter, Emily P. Anderson, Maria C. Trissal, Jenna J. LaBelle, Kendall Carpenter, Leo Kager, Mariella G. Filbin, Katherine A. Janeway. Perspectives from a systematic review of kinase fusion oncogenes and access to corresponding kinase inhibitor clinical trials in pediatric, adolescent, and young adult solid malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2857.