70. A PHASE 1–2 CLINICAL TRIAL OF EO1001, A NOVEL IRREVERSIBLE pan-ErbB INHIBITOR WITH PROMISING BRAIN PENETRATION

Abstract CNS metastasis has become a prominent driver of morbidity and mortality in recent years as new targeted therapies have improved systemic outcomes. Mutations in the ErbB family of kinases are known oncodrivers in many of these cancers. ErbB family member “crosstalk” is associated with rapid development acquired resistance to ErbB TKIs. The development of agents targeting multiple ErbB receptors has shown promise but has been limited by toxicity and poor brain penetration. EO1001 is a first-in-class, oral, brain penetrating, irreversible pan-ErbB inhibitor with superior CNS penetration targeting ErbB1, ErbB2 and ErbB4. Preclinical data suggests a favorable pharmacokinetic and safety profile and promising activity against ErbB-driven cancers in patient-derived xenograft models. Male or female adult participants with confirmed ErbB-positive cancer, including patients with CNS involvement, who have progressed after standard of care therapy, with adequate bone marrow, renal and liver function are eligible. An accelerated dose-escalation design is employed. One subject per dose cohort will be recruited until drug related toxicity (≥G2) is observed in the first dosing cycle, after which dose escalation will revert to a 3 + 3 design to determine the maximum tolerated dose (MTD). Dose Escalation: Cycle 1: Patients will receive a single dose EO1001 on day 1 and single dose pharmacokinetics will be performed. Beginning on day 8, EO1001 will be administered once daily for 21 days; multi-dose pharmacokinetics will be performed. Cycles 2–6: Oral EO1001 will be administered once daily in continuous 28-day cycles for up to 20 weeks. MTD Expansion: Oral EO1001 will be administered once daily at the MTD in continuous 28-day cycles for up to 6 cycles (24 weeks). Toxicity is assessed based on NCI CCTCAEv5 and tumor response will be assessed by RECIST 1.1 or RANO for CNS disease. CNS exposure is evaluated in patients via CSF collection with confirmed CNS disease involvement.