999P JIN-A02, a fourth-generation, highly effective tyrosine kinase inhibitor with intracranial activity, targeting EGFR C797S mutations in NSCLC

Abstract

Even though epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have improved treatment outcomes for EGFR-driven NSCLC, resistance inevitably emerges and disease often progresses due to brain metastasis. The C797S is the most significant resistance mutation to occur after 3rd generation TKIs treatment. JIN-A02 is an orally available EGFR-TKI targeting C797S mutation with high brain penetration. Cellular activities of JIN-A02 were evaluated on phosphorylation-EGFR expression with AlphaLISA assay and on EGFR mutants with patients-derived cell (PDC) and patients-derived organoid (PDO). Different type of allelic relationship was also assessed in all models by whole exome sequencing. Patients-derived xenografts (PDX) was used to assess antitumor activities of JIN-A02. For in vivo intracranial activity, NCI-H1975 cell line derived tumor xenograft was used. In AlphaLISA assay, JIN-A02 showed high potency in EGFRex19del/T790M/C797S (IC50=4.7 nM, Ba/F3), EGFRL858R/T790M/C797S (IC50=12.8 nM, NCI-H1975 LTC). JIN-A02 strongly inhibited cellular activity of in trans model (IC50=89.7 nM, PDO) and in cis model (IC50=92.1 nM, PDC) of EGFRex19del/T790M/C797S. It appears to be superior to osimertinib (IC50 >4,000 nM for both cells). In addition, JIN-A02 showed comparable potency to osimertinib in EGFRex19del/T790M (IC50=84.4 nM for PC-9GR), and EGFRL858R/T790M (IC50=73.3 nM for NCI-H1975). In the PDX mouse model (YHIM-1094, EGFRex19del/T790M/C797S), JIN-A02 delayed tumor growth at a dose of 30 mg/kg. In the brain metastases model, antitumor activity of JIN-A02 was observed with intracranial implanted NCI-H1975 tumors. JIN-A02 is highly potent EGFR-TKI for various EGFR targeted mutations including in cis and trans EGFRex19del/T790M/C797S and shows intracranial activity. Based on these robust activities for EGFR mutants, JIN-A02 is expected to provide a potential therapeutic opportunity for NSCLC.