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EQS-News: Promatix Biosciences, Ltd.
/ Key word(s): Study/Study results
Promatix Biosciences Presents Positive Preclinical Data with First-in-Class PBS293 EGFR×EphA2 Cis-Bispecific ADC Demonstrating Enhanced Tumour Selectivity
London and Cambridge, UK — 24 February 2026 — Promatix Biosciences Ltd (Promatix), an emerging UK-based biotechnology company developing innovative new classes of cancer therapies using cis-bispecific antibodies, today presented positive preclinical data at the 16th World ADC London Summit on its lead molecule, PBS293-MMAE, a first-in-class bispecific ADC for colorectal cancer. PBS293-MMAE was developed using Promatix’s proprietary proteomics-based discovery platform for ADC selection, which systematically analyses tumour and normal tissue surface proteins to identify novel anti-tumour antigen pairs. This approach delivers candidates engineered for cis-bispecific “AND-gate” targeting through hybrid avidity, whereby strong binding occurs when both target antigens are present on the same tumour cell, supporting improved efficacy and reduced toxicity compared to conventional ADC approaches. “The ADC field has made significant progress in payload, linker and conjugation chemistry, yet true tumour-selective targeting remains a major challenge,” said Dr. Michael Hunter, CEO and Co-Founder of Promatix. “Many of the most validated oncology targets, such as EGFR, are also expressed in healthy tissue, which can constrain the therapeutic window and limit efficacy. By utilising our unique capability to identify differentiated antigen pairings and engineering ADCs that depend on dual engagement, we aim to improve selectivity, enhancing both efficacy and safety across novel and validated targets. Our initial focus is in solid tumours where the prevailing standard of care remains inadequate for many patients. The data presented with our lead molecule, PBS293-MMAE, at the 16th World ADC London Summit provide early evidence that this strategy holds the promise of developing therapies with novel mechanisms that can provide meaningful new treatment options for patients.” PBS293-MMAE targets EGFR and EphA2, which are co-expressed in colorectal cancer cells. While EGFR is a clinically validated target in colorectal cancer, benefit from EGFR-targeted therapeutic antibodies such as cetuximab remains limited to a subset of patients, and its utility is restricted by toxicity related to widespread expression of EGFR in healthy tissues. Data presentation highlights Target co-expression: Proteomic analysis combined with FACS (fluorescence-activated cell sorting) analysis of patient-derived colon cancer xenograft tissue have demonstrated high levels of membrane co-localisation of EGFR and EphA2, supporting the biological rationale for dual-target engagement. Hybrid avidity: Hybrid avidity–dependent engagement, in which both antigens are required for binding, has been confirmed for PBS293 in a variety of studies, including cell binding, payload internalisation and cytotoxicity. Improved tumour suppression: In HCT116 colorectal cancer cells, PBS293-MMAE demonstrated low-nanomolar potency over 50-fold greater than cetuximab-MMAE. In a xenograft model, PBS293-MMAE achieved significantly higher dose-dependent tumour growth inhibition and sustained tumour suppression compared to cetuximab-MMAE. Reduced skin toxicity: PBS293-MMAE demonstrated substantially lower cytotoxicity in normal human keratinocytes (skin cells) compared with cetuximab-MMAE, further supporting its tumour-selectivity potential. Detailed results were presented at the 16th World ADC London Summit in a poster entitled: Hybrid Avidity–Gated EGFR/EphA2 Bispecific ADC Enables Tumour Selectivity and Keratinocyte Sparing. The poster can be accessed on the Promatix website here.
PBS293-MMAE is a full IgG1 cis-bispecific antibody–drug conjugate (ADC) targeting EGFR and EphA2 in development for advanced colorectal cancer (CRC). The programme has the potential to address a major unmet need in metastatic CRC. While monoclonal antibodies targeting EGFR, such as cetuximab, are effective in only about 15% of patients[1], PBS293-MMAE is designed to address a broader patient population, independent of RAS/BRAF mutation status and including right-sided colorectal tumours, for which current treatments are ineffective. About Promatix Biosciences Ltd Promatix is a UK-based oncology drug discovery and development company developing next-generation bispecific antibody–drug conjugates (ADCs) through rational, data-driven cis-target pairing. The company’s approach centres on identifying optimal combinations of cancer surface markers for cis-bispecific “AND-gate” targeting, in which strong binding, payload delivery and uptake occur only when two distinct antigens are present on the same tumour cell. This dual-antigen engagement is designed to enhance tumour selectivity. By exploiting hybrid avidity, Promatix aims to reduce on-target off-tumour toxicity and expand the range of targets that can be addressed with ADCs. At the core of the platform is TxPro, a comprehensive tumour surface proteomics database covering membrane proteins across multiple cancer types. TxPro is supported by proprietary computational analytics (CipherPro) to systematically mine tumour-selective antigen pairs, affinity-engineering capabilities (AviPro) to optimise bispecific engagement, and BiPro, a modular functional validation framework for rapid evaluation and lead selection. Promatix is developing a pipeline of novel bispecific ADCs in colorectal cancer and additional solid tumour indications. For more information, visit www.pro-matix.com and follow us on LinkedIn. CONTACT INFORMATION:
24.02.2026 CET/CEST Dissemination of a Corporate News, transmitted by EQS News - a service of EQS Group. |
2280402 24.02.2026 CET/CEST