Abstract 921: Identification of NRG1 fusions in patients with solid tumors: analysis from a real-world community oncology network

Abstract Neuregulin-1 (encoded by NRG1) serves as a ligand for ERBB3 and can lead to dysregulated cellular proliferation in cases of NRG1 fusions. The reported incidence of NRG1 fusions in solid tumors is ~0.1-0.3% with enrichment in invasive mucinous adenocarcinoma of the lung and KRAS wildtype pancreatic adenocarcinoma. However, the real-world incidence of NRG1 fusions across diverse tumor types continues to evolve with the clinical implementation of comprehensive next-generation sequencing (NGS) methods including RNA based NGS. The true diversity and prognostic significance of specific NRG1 fusion partners has yet to be elucidated. We report on NRG1 fusions from a large clinico-genomic database of patients (pts) in community-based oncology settings where NGS is ordered as standard clinical practice. We conducted a retrospective, records-based analysis of pts across Sarah Cannon’s network of over 299 partner community-based oncology clinics to identify pts with NRG1 fusions detected by commercial NGS testing ordered as a part of standard of care from 1/1/2017 - 7/7/2022. NRG1 fusions were reported in 0.05% (19 of 40,857) of pts with commercial NGS test results across a range of tumor types including lung (59%; n=11/19), pancreas (11%; n=2), breast (5%; n=1), colorectal (5%), esophageal (5%), endometrial (5%), soft tissue liposarcoma (5%), and carcinoma of unknown primary (5%). NGS identifying an NRG1 fusion was performed in 5 (26%) pts with early stage disease while 11 (58%) pts had NGS testing after initial diagnosis of or progression to advanced/metastatic disease. A majority of pts harboring NRG1 fusions were female (68%; n=13). NRG1 fusions were detected by DNA (58%; n=11) and RNA based (42%; n=8) NGS from liquid (5%; n=1) and tissue biopsies (95%; n=18). A total of 11 different fusion partners were reported. CD74 was the most prevalent fusion partner and was primarily detected by DNA NGS including in one pt from liquid biopsy. Five novel, as yet to be described, fusion partners (CDK13, IL1RL2, FUT10, PPP2R2A, PIM3) were detected - 3 by RNA sequencing and 2 by DNA sequencing of NRG1 (versus sequencing of the fusion partner). TP53 (42%; n=8), CDKN2A (32%; n=6), and MTAP (16%; n=3) were the most frequently co-altered genes. Other notable co-altered genes included mutations in PIK3CA (11%; n=2), BRAF (5%; n=1), EGFR (5%), ALK (5%), and NRAS (5%). Immune biomarkers were largely negative, with 16% (n=3) PD-L1 positive, 0% MSI-high, and 5% (n=1) TMB-high cases. These data highlight the importance of comprehensive molecular profiling for pts with solid tumors, as NRG1 fusions occur across tumor types and stage of disease. Appropriate test selection is paramount as novel NRG1 fusions are more robustly detected by RNA over DNA NGS and are more routinely detected in tissue over liquid biopsies. Clinical trials investigating therapies to target NRG1 fusions are ongoing [CRESTONE (NCT04383210); eNRGy (NCT02912949)]. Citation Format: Emma G. Sturgill, Jaya Srivastava, Jessica Correia, Cooper Schumacher, Daniel Luckett, Cesar A. Perez, Judy S. Wang, Stephen G. Divers, Babar Bashir, Jennifer Johnson, Valerie M. Jansen, Andrew J. McKenzie, David R. Spigel. Identification of NRG1 fusions in patients with solid tumors: analysis from a real-world community oncology network [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 921.