Circio announces publication of two abstracts selected for presentation at the ASGCT annual meeting

* Circio has been selected for a poster presentation on 13 May and an oral presentation on 15 May at the 2026 ASGCT annual meeting in Boston * ASGCT is the most important and prestigious gene and cell therapy conference globally * The abstracts have been released to the market today, 27 April 2026

Oslo, Norway, 27 April 2026 -- Circio Holding ASA (OSE: CRNA), a biotechnology company developing novel circular RNA expression technology for gene and cell therapy, today announces the publication of two circVec AAV gene therapy abstracts accepted to the American Society of Gene and Cell Therapy annual meeting in Boston 11-15 May 2026. One abstract has been selected for oral presentation, and the other for poster presentation.

The two abstracts to be presented by Circio both relate to the application of its circular RNA-based gene expression technology, circVec, to enhance the performance of AAV gene therapy. The oral presentation will describe the overall circVec platform and highlight its strong performance and versatility across multiple tissues in vivo. The poster presentation will focus more specifically on circVec gene therapy applications in the heart. This presentation summarizes a robust and reproducible data package showing 40-fold enhanced gene expression and the underlying mechanism of action effectuating its substantial increase in performance vs. conventional mRNA-based AAVs.

"ASGCT is the most important event of the year in the gene therapy field, and Circio is very honored that the scientific committee has selected one of our abstracts for an oral presentation," said Dr. Thomas B Hansen, CTO of Circio. "Circio s in vivo data clearly demonstrates that the circVec technology has the potential to transform conventional AAV gene therapy. The ASGCT presentation will be an important opportunity to showcase the performance and versatility of our circVec platform for gene and cell therapy applications to prospective pharma partners and a wider life science industry and academic audience."

The ASGCT annual meeting is the largest and most prestigious gene and cell therapy conference globally, and widely attended by pharmaceutical and biotech professionals, academics and life science media. Only a small number of submitted abstracts are accepted for oral presentation.

Circio R&D management will present the two attached abstracts at ASGCT 2026:

Circular RNA-based AAV gene therapy for cardiomyopathies enhances transgene expression levels, reduces liver off-targeting and minimizes cellular stress O Leary et al., poster presentation, Wednesday 13 May 2026

circVec: A powerful circular RNA expression platform that enhances AAV transgene output and enables significant dose reduction O Leary et al., oral presentation, Friday 15 May 2026 at 16:15 EST

The materials will be made available on the Circio website shortly after the ASGCT presentations.

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

Circio Holding ASA is a biotechnology company developing novel circular RNA expression technology for gene and cell therapy.

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 50-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.