This patent application (HK 40130705 A) describes recombinant production methods enabling controlled incorporation of xylosylated N‑glycans - key structures influencing antigen properties - into complex protein antigens, leveraging ExpreS2ion’s proprietary Drosophila S2‑based expression technologies. The invention strengthens the Company’s position in glyco‑engineering and advanced antigen design, reinforcing ExpreS2ion’s platform differentiation and supports future partnering and development opportunities.

Highlights

• Strengthens ExpreS2ion’s differentiated glyco-engineering capabilities within the ExpreS2™ platform.
• Enables design of antigen structures with improved immunogenic and functional properties.
• Expands IP coverage supporting long-term partnering and licensing opportunities.

Bent U. Frandsen, CEO of ExpreS2ion, comments
“The publication of this patent application in Hong Kong represents an important milestone in our ongoing effort to secure broad global protection for our advanced glyco‑engineering technologies. These methods contribute directly to the differentiated quality of the antigens we develop, and this milestone strengthens the foundation for future collaboration and commercial opportunities in Asia.”

Dr. Max M. Soegaard, CSO of ExpreS2ion, comments
“Xylosylated N‑glycan structures are increasingly important for fine‑tuning antigen performance. This published application highlights our ability to engineer targeted glycosylation outcomes within recombinant proteins, supporting our ambition to develop best‑in‑class immunotherapies and vaccines.”

Next Steps
Following publication, the application will proceed through the standard HKIPD examination process. ExpreS2ion will communicate additional updates as the patent advances toward subsequent procedural milestones.

About glycoengineering in Drosophila S2 cells and the prospects
By modifying specific biochemical pathways in our Drosophila S2 cell lines, we enable them to alter the surface properties of the proteins they produce. These modifications can significantly enhance the immune response to a protein, making the resulting immunotherapy or vaccine much more effective while also reducing production costs. We are continually developing these GlycoX-S2 cell lines to further refine the ExpreS2™ system's full potential for creating novel biologics.

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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: investor@expres2ionbio.com

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.