Malaria remains one of the world’s most persistent infectious diseases, with existing vaccines offering limited protection once the parasite enters the bloodstream. RH5 is widely regarded as a leading blood-stage target for Plasmodium falciparum malaria due to its essential role in this parasite’s invasion and its high conservation across strains.

BIO-002, a Phase Ia clinical study in healthy UK adults conducted in partnership by the Universities of Oxford and Sheffield, was designed to assess the safety and immunogenicity of the RH5.1 protein formulated with Matrix-M® adjuvant using two dosing strategies. The study was funded primarily by the UK Medical Research Council. The RH5.1 antigen used in the study is produced using ExpreS2ion’s proprietary Drosophila S2 expression platform.

The data demonstrate:

• A favourable safety profile, with no serious adverse events reported
• Consistent antibody responses with functional activity against the malaria parasite
• Comparable immunogenicity across dosing regimens

Importantly, BIO-002 shows that a standard-dose regimen achieves similar immune responses to a higher-dose approach. This finding supports more efficient antigen use, with potential to improve manufacturing efficiency at scale, and may enable simpler and more scalable vaccine deployment strategies in future development.

For ExpreS2ion, these results add to a growing body of clinical evidence supporting the use of its platform in vaccine development. Beyond immunogenicity, the data underscore a key requirement for global health solutions: the ability to combine biological performance with scalable and cost-efficient manufacturing.

BIO-002 also illustrates the Company’s partnered development model. The RH5.1 antigen, developed by the Department of Paediatrics at the University of Oxford, is part of a broader collaboration with the Serum Institute of India, reflecting an approach in which ExpreS2-enabled assets can be advanced and scaled through external partnerships. This model enables ExpreS2ion to partner on the generation of clinically validated assets, while retaining strategic focus on internally developed programmes such as ES2B-C001.

The results further support the applicability of the ExpreS2 platform across the Company’s pipeline, including its lead oncology programme, ES2B-C001. While developed in a different therapeutic setting, the data provide additional clinical validation of the underlying expression system used in ES2B-C001, supporting confidence in its manufacturability and clinical development.

Max Søgaard, CSO of ExpreS2ion, commented:
“BIO-002 addresses a fundamental question in vaccine development: not just whether a candidate works, but whether it can be dosed for delivery at scale. These results support both. For ExpreS2ion, they provide further validation that our platform is aligned with the real-world demands of global vaccine deployment, while also supporting our broader pipeline strategy.”

The study is available as a preprint and has not yet been peer reviewed: Read the BIO-002 preprint

ExpreS2ion is not the sponsor of the clinical trial.

About the Department of Paediatrics
The Department of Paediatrics at the University of Oxford is a global leader in the research, delivery and advancement of the health and care of children and adolescents. It hosts internationally renowned programmes in drug development, gastroenterology, haematology, HIV, immunology, neuroimaging, neuromuscular diseases and vaccinology to name a few, and its work spans from early proof-of-concept and fundamental science to its application in clinical settings. The Department of Paediatrics’ pioneering research, policy development and clinical excellence is led by world-class experts in their field and it has a long track record of success in the development and delivery of effective treatments and interventions. Its work is supported by the clinical and educational resources of one of the world’s foremost academic institutions.

Certified Adviser
Redeye Nordic Growth AB

The information was sent for publication, through the agency of the contact persons set out above, at the time stated by the Company’s news distributor, MFN, at the publication of this press release.

For further information about ExpreS2ion, please contact:
Bent U. Frandsen, CEO
Keith Alexander, CFO
Email: [email protected]

About ExpreS2ion
ExpreS2ion is a biotechnology company focused on the development of innovative active immunotherapies and vaccines for cancer and infectious diseases. The company has developed the ExpreS2™ platform, a proprietary protein expression technology used across more than 500 recombinant protein and virus-like particle (VLP) projects spanning research, diagnostics, and therapeutic development. Proteins produced using the ExpreS2 platform are being evaluated in multiple clinical programmes worldwide. The platform has also been applied in partnered development programmes that have progressed into late-stage clinical evaluation, including Phase III studies that have met their primary endpoints. The platform, marketed as GlycoX-S2™, includes functionally modified glycosylation variants designed to enhance immunogenicity and pharmacokinetics. ExpreS2ion develops novel VLP-based vaccines in association with AdaptVac ApS, of which ExpreS2ion owns 34%. ExpreS2ion Biotech AB is listed on Nasdaq First North Growth Market. For additional information, please visit www.expres2ionbio.com.