Circio delivers three presentations at ESGCT and shows novel AAV circVec 5.2 design for enhanced heart expression and specificity

• New heart-optimized circVec 5.2 design shows approximately 200-fold higher gene expression compared to conventional AAV vectors, with 95% cardiac specificity and less than 1% off-target expression in liver
• The competitive oral presentation at ESGCT follows the ASCGT presentation in May, marking back-to-back selections at the two leading global gene and cell therapy conferences
• In the oral presentation, Circio is showcasing the versatile circVec circular RNA gene expression platform, with a focus on non-viral vectors for in vivo cell therapy applications
• Two posters demonstrate the potential of circVec to enhance gene expression and specificity across heart, eye and CNS, supporting the development of more effective and safer gene therapies

Oslo, Norway, 28 October 2026 – Circio Holding ASA (OSE: CRNA), a biotechnology company developing novel circular RNA expression technology for gene and cell therapy, today announces the materials for its oral and two poster presentations that are being delivered at the 33rd Annual Congress of the European Society of Gene and Cell Therapy (ESGCT) in Hamburg, Germany.

In the oral presentation, Circio´s CTO Dr. Thomas B Hansen presents the latest developments for its circVec platform and its potential for in vivo CAR-T therapy, an area attracting significant momentum in the life sciences industry. Circio´s approach formulates circVec DNA constructs into LNP particles with the aim to establish a novel technology platform for potent, durable and immune-quiet CAR expression in T-cells. This unique combination could establish a new in vivo therapeutic window for cancer and autoimmunity, bridging the gap between transient, short-lived RNA-based approaches and permanently integrating, irreversible lentiviral systems.

“Presenting the evolution of the circVec technology from the first to the fifth generation in an oral session at ESGCT is an excellent opportunity to show how far the platform has come and its range of therapeutic applications,” said Dr. Thomas B Hansen, CTO of Circio. “Across heart, eye and CNS, circVec delivers strong, specific and consistent expression gains over conventional AAV gene therapy, driven by the superior stability of circular RNA. The broad and robust performance makes circVec a platform technology that can be applied across different vectors, tissues and diseases. With each new generation we have further improved both potency and precision, and we see substantial potential for circVec as an integral component of next generation gene and cell therapies.”

The two posters highlight the potential of circVec to improve the potency and specificity of AAV vectors to support the development of more effective next generation gene therapies. circVec 3.2 and 4.0 show up to approximately 40-, 50- and 60-fold increased expression in heart, eye and CNS, respectively. The new heart-optimised AAV9 circVec 5.2 design further enhances potency and cardiac specificity, achieving approximately 200-fold higher gene expression than conventional mRNA-based AAV9. Importantly, circVec 5.2 shows 95% heart-specific expression, compared with 25% for conventional mRNA-based AAV9, while reducing off-target liver expression to less than 1%, compared with 9% for conventional AAV9. These results highlight the ability of circVec to enhance on-target tissue activity while minimizing unwanted payload expression in off-target tissues, an important feature for enabling more specific gene therapies and reducing toxicity.

“Being selected for a competitive oral presentation at both the ASGCT and ESGCT 2026 annual meetings reflects the growing recognition of Circio in the gene and cell therapy field,” said Dr. Erik D Wiklund, CEO of Circio. “Following the new and enhanced circVec 5.2 design and validation in vivo, Circio is advancing its pre-clinical cardiac program. This is an area where circVec really stands out, with strong potential to offer enhanced and safer gene therapies for patients with high and urgent medical needs. With the USD 88 million in new funding secured during 2026, Circio is now rapidly progressing into in vivo heart disease models to confirm the potential of AAV-circVec in therapeutic systems. Studies are starting in first quarter 2027, and we can look forward to several important read-outs during the year.”

Circio presentations at ESGCT Annual Congress 2026:

circVec: A DNA Vector Platform Harnessing Intracellular Circular RNA Biogenesis for Next-Generation T Cell Therapies
Dr. Thomas B Hansen, oral presentation
Session: Non-viral vectors/nanotechnology and RNA therapeutics I
10:00am Wednesday 28 October 2026

circVec Reduces AAV Vector Dose Through Durable and Potent Circular RNA Expression
O´Leary et al., poster presentation
Poster Session I: AAVs/non integrative vectors
Wednesday 28 October 2026

AAV-circVec Enhances Cardiac Expression While Minimizing Dose and Cellular Stress
Hansen et al., poster presentation
Poster Session II: Cardiovascular & Muscular Diseases
Thursday 29 October 2026

The materials are attached to this press release and are made available on the Circio website.

Circio plans to host an R&D webcast at the end of November to discuss the ESGCT data in more detail and present results from ongoing in vivo studies in heart and eye that are expected to complete during November.