OncoBayes targets ADC resistance and brain penetration with OB-001

OB-001 functions as a daily oral tablet that inhibits the P-gp and BCRP efflux pumps found on both the blood-brain barrier and tumor cells. In preclinical perfused-brain mouse studies, the compound significantly boosted brain exposure to four gold-standard kinase inhibitors without altering systemic plasma levels. Specifically, data presented at AACR 2026 showed a 400% increase in osimertinib brain exposure, a result expected to improve progression-free survival for EGFR-mutated non-small cell lung cancer patients struggling with brain metastases.

Beyond CNS penetration, OncoBayes is positioning OB-001 as a solution to ADC resistance. By suppressing the same efflux pumps responsible for pumping payloads out of tumor cells, the drug demonstrated the ability to reduce efflux for payloads such as SN-38, DM4, and DXd. CEO Jim Millen noted that the company is now preparing for a parallel clinical trial program to generate proof-of-concept data for both osimertinib combinations and T-DXd re-sensitization. The firm views the candidate as a first-in-class adjunct capable of enhancing the performance of existing blockbuster therapies.