Released: Friday 21st March 2025

Data presented at ESMO meeting demonstrate significant activity of first-in-class therapeutic

Medannex Ltd (Edinburgh) today revealed new data showing that its first-in-class antibody therapeutic (MDX-124) has significant anti-cancer activity in pre-clinical models of osteosarcoma.

Osteosarcoma is a rare primary cancer of the bone characterised by its aggressive, highly invasive nature, rapid disease progression and high mortality rate. It is a disease primarily of children and adolescents, and patient outcomes have stagnated in the last 40 years so there remains a real unmet clinical need for novel targeted therapies.

MDX-124 adopts a new and different approach to treatment. It is the first therapeutic candidate to target annexin-A1 (ANXA1), a phospholipid-binding protein that is overexpressed in numerous cancers. High levels of ANXA1 correlate with poor patient outcomes, tumour growth and metastatic spread.

The new data, presented at the European Society of Medical Oncology (ESMO) Sarcoma and Rare Cancers Congress in Switzerland, demonstrate that ANXA1 is highly expressed in osteosarcoma and that treatment with MDX-124 reduces the viability of osteosarcoma cells. In addition, the monoclonal antibody significantly inhibits osteosarcoma cell migration in a dose dependent manner. The poster presentation was co-authored by Medannex, Prof Chris Parris’ team at ARU (Cambridge, UK), Prof Chris Pepper at Brighton and Sussex Medical School (Brighton, UK) and Dr Anand Patel at St. Jude Children’s Research Hospital (Memphis, TN, USA).

Medannex, a finalist at Scotland’s Life Sciences Awards earlier this month, was recently awarded an Innovate UK ‘Transforming Cancer Therapeutics’ grant to prepare MDX-124 for a clinical study in paediatric osteosarcoma. The project’s Clinical Advisory Board is led by Prof. Pamela Kearns (Chair of Clinical Paediatric Oncology, University of Birmingham).

Last year the Nature journal Oncogene published data demonstrating the multi-faceted anti-cancer activity of MDX-124 in models of other difficult to treat cancers including pancreas, triple-negative breast, colorectal, lung and ovarian. The first-in-class therapeutic has also shown significant synergy with various commonly used chemotherapies and immunotherapies, as well as a benign safety profile in toxicology studies.

An ongoing Phase 1b first-in-human study (ATTAINMENT) is producing promising signals, and cohorts have been completed at doses ranging from 1 to 30 mg/kg, with no dose-limiting toxicities observed. Once the optimum dose has been established, MDX-124 will be evaluated in recently diagnosed cancer patients, as a single agent and in combination with standard-of-care chemotherapies.

Medannex CEO Ian Abercrombie said: ‘MDX-124 has huge potential to treat numerous cancers and other conditions, and the osteosarcoma data presented at the ESMO meeting demonstrate a significant new opportunity to make a difference to patients. This is another great endorsement of the Medannex team and we’re very grateful to our expert collaborators in the UK, mainland Europe and the USA. We look forward to initiating clinical studies in this area of high unmet need.’

About Medannex Ltd: Medannex is a clinical-stage Scottish biopharmaceutical company headquartered in Edinburgh. The company is developing novel treatments for various cancers, autoimmune diseases and other conditions, by targeting annexin-A1: https://medannex.org

About MDX-124: MDX-124 is a humanised monoclonal antibody, and the first clinical-stage agent that specifically targets and inhibits annexin-A1, a protein that plays a key role in the development of cancers, autoimmune diseases and other conditions.

About the ATTAINMENT clinical study: The ATTAINMENT study is a modular, multi-arm, first in human study to evaluate the safety and tolerability of MDX-124, alone and in combination with established anti-cancer treatments, in participants with locally advanced, unresectable or metastatic solid malignancies.

Medannex Ltd enquiries – email jamesingham@medannex.org