· New and strengthened circVec in vivo expression data presented for both viral
and non-viral vector formats
  · circVec demonstrates a distinct pattern of expression in vivo compared to
equivalent mRNA-based vectors
  · The data confirms the potential of circVec as a powerful expression system
for cell and gene therapy, indicating novel opportunities to target tissues and
diseases where conventional gene therapy technology is unsuitable

Oslo, Norway 14 May 2025 - Circio Holding ASA (OSE: CRNA), a biotechnology
company developing powerful circular RNA technology for next generation nucleic
acid medicine, today announces the presentation of new and strengthened in vivo
data at the American Society of Gene and Cell Therapy (ASGCT) annual meeting
2025 in New Orleans, USA.

In the poster presentation, Circio is showcasing its latest in vitro and in vivo
results for the circVec platform. circVec continues to demonstrate broad
capability to significantly boost protein expression level and durability for
both viral and non-viral gene and cell therapy.

Importantly, new results show that both viral and non-viral circVec vectors
display tissue patterns that are distinct from equivalent mRNA-vectors. The
 pattern is hallmarked by increased protein expression in muscle, heart and
spleen, and consistently low in liver. These surprising observations demonstrate
a fundamental biological difference between circRNA and mRNA-based expression
and show that the circVec platform has advantages that can open new therapeutic
opportunities where current gene therapy approaches fall short.

"Circio is rapidly expanding the in vivo circVec data package, with several
recent intriguing advances. It has become evident that circVec not only offers
increased protein expression level and durability in general, but also that this
effect is associated with a distinct tissue profile. These results provide a
valuable roadmap to direct our R&D activities and develop a therapeutic strategy
focused on areas that are not well served by existing gene therapy approaches."
said Dr. Thomas B. Hansen, CTO of Circio. "We selected the prestigious ASGCT
meeting to present our latest results as it provided a great opportunity to
showcase our technology to a broad life science audience and potential
partners."

In addition, Circio is continuing to progress its circVec-AAV gene therapy
development for muscular dystrophies and cardiomyopathies. Longitudinal in vivo
data up to six months show a general overall advantage of circVec expression at
low dose levels. Enhanced target tissue expression and reduced liver
accumulation is also observable with circVec-AAV vectors, indicating that the
circVec advantage is more pronounced in specific tissues and therapeutic
settings. Follow-up analyses and testing of novel circVec-AAV variants are
currently ongoing to further explore these observations and identify the most
favorable opportunities for circVec-AAV gene therapy development.

Title of presentation:
CircVec: a powerful circular RNA expression platform to enhance viral and non
-viral gene and cell therapies

Time and poster number:
13 May 2025, 18:00-19:30hrs CDT, poster #655

Location:
Ernest N. Morial Convention Center, New Orleans, Louisiana, USA

The poster is attached to this press release and is available on CircioŽs
webpage (http://www.circio.com/)

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 7821 255568 (http://tel:+447821255568)
Email: neiljameshunter@gmail.com

About Circio

Building next generation RNA technology for nucleic acid medicine

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
platform for novel DNA, RNA and viral therapeutics. The proprietary circVec
technology is based on a modular genetic cassette design for efficient
biogenesis of multifunctional circRNA inside cells, which can be deployed in
multiple therapeutic settings, including genetic medicine, cell therapy and
chronic disease. The circVec platform has demonstrated up to 15-fold enhanced
and more significantly more durable protein expression vs. classic mRNA vector
systems and has the potential to become a new gold-standard platform technology
for nucleic acid and viral therapeutics in the future. The circRNA R&D
activities are being conducted by the wholly owned subsidiary Circio AB based at
the Karolinska Institute in Stockholm, Sweden.

In addition, Circio is developing a pan-RAS cancer vaccine, TG01, targeting KRAS
driver mutations. TG01 is currently being tested in two clinical trials: RAS
-mutated pancreatic and lung cancer in the USA and multiple myeloma in Norway.
These studies are being run through academic and industry collaborative
networks, supported by prestigious research grants from Innovation Norway and
the Norwegian Research Council, creating read-outs and future optionality for
the program at low cost to Circio.

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 article 17 and section 5-12 of the Norwegian Securities Trading
Act.

This stock exchange announcement was published by Erik Digman Wiklund, CEO, on
behalf of the Company, at the time and date stated above in this announcement.