The ROS1 receptor tyrosine kinase can be aberrantly activated by gene rearrangements that generate oncogenic ROS1 kinase fusions. ROS1 fusions have been detected in diverse adult and pediatric cancers including up to 2% of non-small cell lung cancers (NSCLC), 1-9% of cholangiocarcinomas, and 0.5-1% of gliomas and glioblastomas. There are over 50 known fusion partners of ROS1. Notable examples include CD74, EZR, SDC4, and SLC34A2 in NSCLC; GOPC exons 1-3 (short form or GOPC(S)) in cholangiocarcinoma; and GOPC exons 1-7 (long form or GOPC(L)) in glioblastoma. Crizotinib and entrectinib are FDA-approved ROS1 tyrosine kinase inhibitors (TKIs), but clinical emergence of ROS1 resistance mutations S1986F/Y, F2004C/I/V, L2026M, G2032R, and D2033N restricts their therapeutic utility. Due to the diversity of ROS1 fusion partners and kinase-domain mutations, development of novel ROS1 inhibitors that retain potency against fusion variants and resistance mutations would be beneficial to address these clinical needs.

NVL-520 is a novel, brain-penetrant ROS1-selective inhibitor that exhibits preclinical activity against ROS1 alterations, including resistance mutations, while also sparing inhibition of TRKB. TRKB inhibition in the central nervous system has been implicated in adverse events observed with FDA-approved dual TRK/ROS1 inhibitor entrectinib and FDA-approved ALK inhibitor lorlatinib. We previously reported the activity of NVL-520 in several cell line and xenograft models bearing CD74-ROS1, EZR-ROS1, and SDC4-ROS1 fusions, with a wild-type kinase domain or a G2032R mutation. Here we report a broader comparative characterization of NVL-520 and other ROS1 inhibitors against a diverse set of ROS1 fusion partners and kinase-domain mutations.

NVL-520 showed potent suppression of proliferation and/or ROS1 signaling in Ba/F3, NIH3T3, or human cancer cell lines expressing CD74-, EZR-, SLC34A2-, or GOPC(L)-ROS1 fusions. NVL-520 also retained potent inhibition of Ba/F3 cells expressing ROS1 fusions with F2004C, F2004V, G2101A, or G2032R mutations. To further demonstrate the broad activity of NVL-520, we utilized NIH3T3 cells expressing CD74- or EZR-ROS1 fusions with G2032R or F2004C mutations. NVL-520 robustly suppressed colony formation and downstream effector signaling in the ROS1 G2032R and F2004C resistance mutant context. Lastly, NVL-520 demonstrated inhibition of ROS1 signaling in a human glioblastoma cell line U118MG, which harbors the GOPC(L)-ROS1 fusion. In conclusion, the preclinical profile of NVL-520 supports its potential to address a medical need for patients with a diverse array of ROS1 fusion partners and kinase-domain mutations, both in NSCLC and in other cancers such as glioblastoma. NVL-520 is being evaluated in a Phase 1/2 clinical trial for patients with advanced ROS1-positive NSCLC or other solid tumors (NCT05118789).

Citation Format: Anupong Tangpeerachaikul, Clare Keddy, Katelyn Nicholson, Monika Davare, Henry E. Pelish. Preclinical activity of NVL-520 in ROS1-driven cancer models with diverse fusion partners and kinase-domain mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3336.