Circio to present comprehensive circVec-AAV in vivo data package at ESGCT 2025

* Circio will present its circVec expression platform at the European Society of Gene and Cell Therapy (ESGCT) annual meeting, taking place on 7-10 October 2025 in Seville, Spain * In the presentation, Circio will summarize the most recent development of circVec-AAV in vivo demonstrating significant advantages over conventional AAVs in heart and other tissues * ESGCT is one of the most prestigious and widely attended international conferences in the gene and cell therapy field

Oslo, Norway 1 October 2025 -- Circio Holding ASA (OSE: CRNA), a biotechnology company developing powerful circular RNA technology for next generation nucleic acid medicine, today announces that the European Society of Cell and Gene Therapy (ESGCT) has selected a Circio abstract for poster presentation at its annual meeting 2025. The presentation will detail how Circio is enhancing gene and cell therapy using circVec, its circular RNA vector expression technology. Specifically, Circio will summarize recent in vivo results demonstrating significant advantages of its circVec-AAV platform over conventional AAVs in heart and other tissues.

"Circio s most recent in vivo results continue to demonstrate circVec s strong potential as a novel expression system for enhanced gene and cell therapy. The prestigious ESGCT annual meeting provides an excellent opportunity for us to showcase our latest pre-clinical data to a wide industry and academic audience," said Dr. Thomas B. Hansen, CTO of Circio. "At this year s conference, we will present the major advances we have made to enhance conventional AAV gene therapy using the circVec platform, showing statistically significant increases in expression in multiple tissues for several circVec-AAV variants."

Title of presentation: CircVec: Enhancing gene and cell therapy using circular RNA vector expression technology (poster no. 1041)

Presenter: CTO Dr. Thomas B Hansen & CSO Dr. Victor Levitsky

Time: 14:00hrs CEST, 8 October 2025

Location: Fibes, Seville, Spain

For further information, please contact: Erik Digman Wiklund, CEO Phone: +47 413 33 536 Email: erik.wiklund@circio.com

Neil Hunter -- Hunter PR Phone: +44 782 125 5568 Email: neiljameshunter@gmail.com

About Circio Building circular RNA expression systems for enhanced gene and cell therapies

Circio Holding ASA is a biotechnology company developing powerful circular RNA vector expression technology for next generation nucleic acid medicine.

Circio has established a unique circular RNA (circRNA) vector expression technology for next generation RNA, DNA and viral therapeutics. The proprietary circVec platform is based on a modular genetic construct designed for efficient biogenesis of multifunctional circRNA inside target cells. The circVec platform has applications in multiple therapeutic settings, including genetic medicine, cell therapy and chronic disease. It has demonstrated 75-fold increased RNA half-life and up to 40-fold enhanced protein expression vs. conventional mRNA-based viral and non-viral vector systems, with the potential to become a new gold-standard gene expression technology. The circVec R&D activities are being conducted by the wholly owned subsidiary Circio AB in Stockholm, Sweden.