Secreted gaussia luciferase expressing PC9 cells, which were derived from EGFR exon 19 deletion NSCLC, were intracranially injected into female NSG mice and were randomized into the following treatment groups: vehicle, osimertinib at 10 and 25 mg/kg (mpk) and ERAS-801 at 10 and 25 mpk (n = 8 mice per group)....ERAS-801 at 10 and 25 mpk achieved significantly greater tumor regressions than osimertinib in an intracranial EGFR mutant NSCLC PC9 CDX study.