OncoBayes OB-001 preclinical data show potential to overcome ADC resistance and TKI brain penetration
OncoBayes announced successful preclinical work with OB-001, demonstrating its potential to address ADC resistance and improve TKI brain penetration. In mouse studies, OB-001 increased brain exposure of kinase inhibitors by almost 400% without significantly impacting systemic exposure.
2026 / 08:05 CET/CEST The issuer is solely responsible for the content of this announcement. ════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════ LONDON, Oct. 7, 2026 // — OncoBayes, a privately held clinical-stage pharmaceutical company, today announced the successful completion of preclinical work with OB-001, demonstrating the product's potential to tackle two major unmet needs in oncology: ADC resistance and the brain penetration of tyrosine kinase inhibitors (TKIs).
OB-001 is a highly selective and effective inhibitor of two key efflux pumps (P-gp and BCRP), which are present both on the blood-brain barrier and on tumour cells. The product is being developed as a once-daily oral tablet, which will be used in combination with a number of gold standard oncology treatments in order to optimise their efficacy. In perfused-brain mouse studies, OB-001 pretreatment significantly raised brain exposure of four gold standard kinase inhibitors — whilst systemic (plasma) exposure remained broadly unchanged.
Data presented at AACR 2026 demonstrated that OB-001 could increase the brain exposure of osimertinib by almost 400% with minimal systemic changes^ 1, 2. Based on a translational PK-PD-TGI model for osimertinib, this increase is projected to deliver a step-change in CNS progression-free survival for EGFRm NSCLC patients. The improved control of brain metastases is still a major area of unmet need in NSCLC and breast cancer. The same efflux pumps have also been identified as a key resistance mechanism impacting ADCs — with the over-expression of these pumps leading to reduced payload concentrations in the tumour.
g. g. g. trastuzumab deruxtecan, Enhertu®).
Plans are currently underway to move into a parallel clinical trial programme to generate POC data in combination with osimertinib, and also evaluate T-DXd re-sensitisation. "This is a critical milestone for our team, and we are now well positioned to initiate our clinical plans with OB-001" said Jim Millen, Chief Executive Officer for OncoBayes. "OB-001 is on track to become a first-in-class drug with broad potential as a simple, oral adjunct to a range of blockbuster oncology therapies. " References: ^1.
AACR2026 Abstract 5873. 1 April 2026; 86 (7_Supplement): 5873. 1 ^2. Cancer Research Communications 1 May 2026; 6 (5): 1213—1219.
2026 CET/CEST Dissemination of a Corporate News, transmitted by 6 EQS News — a service of 7 EQS Group. The issuer is solely responsible for the content of this announcement. The EQS Distribution Services include Regulatory Announcements, Financial/Corporate News and Press Releases. 2026 CET/CEST References Visible links 1.
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