Abstract 1466: ORIC-114, a brain penetrant, orally bioavailable, irreversible inhibitor selectively targets EGFR and HER2 exon20 insertion mutants and regresses intracranial NSCLC xenograft tumors

Genomic insertions within exon20 of both epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) are oncogenic drivers most commonly found in non-small cell lung cancer (NSCLC) but also occurring in multiple other tumor types. Exon20 insertions render the receptors resistant to currently approved inhibitors, giving patients with tumors harboring such insertions a worse prognosis than with other activating EGFR mutations. Moreover, approximately one-third of patients with exon20 insertion mutations may develop central nervous system (CNS) metastases over the course of their disease. To address this unmet medical need, ORIC-114, a brain penetrant, orally bioavailable, irreversible small molecule inhibitor was designed to target exon20 insertions in EGFR and HER2. ORIC-114 is highly selective to the EGFR family of receptors, showing superior kinome selectivity compared with other reported exon20 inhibitors. In biochemical assays ORIC-114 displays low nanomolar potency, and importantly has enhanced potency on the EGFR exon20 NPG insertion relative to wildtype EGFR protein. ORIC-114 also demonstrates low nanomolar potency across exon20 insertion variants using cell-based assays measuring EGFR phosphorylation, downstream signaling and cell viability. ORIC-114 is readily brain available across multiple preclinical species hence studies were undertaken to investigate activity in both subcutaneous and intracranial tumor models. Herein, we explored the in vivo activity of ORIC-114. Consistent with our in vitro findings, robust activity was observed in EGFR exon20 patient-derived xenograft models using once daily oral administration, with greater than 90% tumor growth inhibition in the absence of body weight loss. Moreover, these significant antitumor effects correlate with decreased pharmacodynamic response as measured by phosphorylated EGFR in terminal tumors. To investigate whether the brain-penetrant attributes of ORIC-114 translate into therapeutic CNS activity, we utilized an intracranial luciferase-labeled EGFR mutant cell line model. Once daily oral administration of ORIC-114 significantly regressed established intracranial NSCLC tumors, demonstrating greater efficacy than TAK-788, commensurate with the superior brain to plasma exposure of ORIC-114. Taken together, these data establish ORIC-114 as a selective, irreversible, and brain penetrant EGFR inhibitor, making it a promising therapeutic candidate for development in patients with tumors harboring EGFR and HER2 exon20 insertions, including those with CNS metastases. ORIC-114 is anticipated to enter a global Phase 1/2 tumor-agnostic trial in genetically defined cancers in the second half of 2021. Citation Format: Melissa R. Junttila, Sunghwan Kim, Younho Lee, Hwan Kim, Juhee Kang, Jiyoon Seok, Jihye Yoo, Youngyi Lee, Dong-Hyuk Seo, Jung Beom Son, Daekwon Kim, Hwan Geun Choi, Nam Doo Kim, Akash Das, Dena Sutimantanapi, Tatiana Zavorotinskaya, Chelsea Chen, Jae Chang, Matthew Panuwat, Lori Friedman. ORIC-114, a brain penetrant, orally bioavailable, irreversible inhibitor selectively targets EGFR and HER2 exon20 insertion mutants and regresses intracranial NSCLC xenograft tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1466.