Circio Holding ASA

Regulatory Filings • May 13, 2025

Circular RNA innovator Circio presents strengthened circVec gene therapy data at ASGCT 2025

Circular RNA innovator Circio presents strengthened circVec gene therapy data at ASGCT 2025

· 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 Circio´s

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.