Circio presents new and extensive circVec data at ASGCT supporting substantial AAV dose reduction

15 May 2026 22:15 CEST

* Circio unveils extensive circVec-AAV data package in the poster session on
13 May and as an oral presentation on 15 May at the 2026 ASGCT Annual
Meeting in Boston
* The data supports the potential of the circVec circular RNA-based expression
system to enable substantial dose reduction, addressing a key challenge for
developing safer and lower cost AAV gene therapies
* ASGCT is currently the most important and prestigious gene and cell therapy
conference globally

Oslo, Norway, 15 May 2026 -- Circio Holding ASA (OSE: CRNA), a biotechnology
company developing novel circular RNA expression technology for gene and cell
therapy, today publishes the poster and slides that were presented at the
American Society of Gene and Cell Therapy Annual Meeting in Boston.

In the oral presentation, Circio s CEO Dr. Erik D Wiklund provided an overview
and the latest developments of the circVec circular RNA-based gene expression
platform. The superior stability of circular RNA enables enhanced and
prolonged gene expression and can be deployed to enable more potent and safer
gene and cell therapies. In the context of AAV gene therapy, circVec yields up
to 40 and 50-fold increased gene expression in heart and eye, respectively.
High dosing requirements and associated toxicities remain critical barriers to
the broader clinical application of AAV gene therapy. Preclinical studies
suggest that the circVec technology can enable AAV dose reduction, potentially
improving safety and expanding treatment opportunities for patients with rare
genetic disorders.

The poster presentation detailed an extensive circVec-AAV in vivo data
package in heart tissue. circVec shows significant promise for cardiac
genetic disease, delivering 40-fold increased gene expression from AAV9
vectors compared to conventional AAV technologies. Importantly, molecular
analyses performed on heart tissue confirm that the circVec advantage, as
expected, is driven by the superior durability of circular RNA. Moreover,
these findings are consistent across a broad dose range, with circVec
demonstrating enhanced expression and distribution within the heart
across all dose levels.

"ASGCT is the most important event of the year in the gene therapy field, and
Circio is very honored to be selected for an oral presentation in this forum
of global expertise," said Dr. Erik D Wiklund, CEO of Circio. "The ASGCT
meeting is also an excellent opportunity to connect with existing and
prospective collaboration partners. The robust circVec data package, combined
with high demand for novel circular RNA approaches, continues to trigger
substantial visibility for and interest in Circio and our unique technology
platform."

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, patient advocacy groups and life science media.

Circio presentations at ASGCT Annual Meeting 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
Session: Cardiac disease models, Wednesday 13 May 2026

circVec: A powerful circular RNA expression platform that enhances AAV
transgene output and enables significant dose reduction

Dr. Erik D Wiklund, oral presentation
Session: New insights into AAV genome biology, Friday 15 May 2026

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

This information is considered to be inside information pursuant to the EU
Market Abuse Regulation (MAR) and is subject to the disclosure requirements
pursuant to MAR and section 5-12 of the Norwegian Securities Trading Act. The
information was submitted for publication at 2026-05-15 22:15 CEST.

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

Lubor Gaal, CFO
Phone: +34 683 34 3811
Email: lubor.gaal@circio.com

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.

More information:
Access the news on Oslo Bors NewsWeb site

673641_260515 ASGCT Circio.pdf
673641_2026 ASGCT Poster.pdf