Circio Holding ASA

Regulatory Filings • Mar 5, 2025

Circular RNA expression systems for enhanced gene and cell therapies

Dr Erik D Wiklund, CEO

RNA Leaders Congress Basel, 5 March 2025

• 1. circVec platform
• 1. circVec therapeutic development

Human circRNA was first described by Circio scientists

30 September 2011 1,000 citations January 2025

circRNA increases durability and expression level to enhance the potency of nucleic acid medicines

1. circVec therapeutic development

The unique circVec expression system: Turning the patient´s cells into circRNA factories

circVec DNA or viral vector

Inject

circRNA biogenesis

Potent and durable protein expression

The circVec platform is technologically differentiated and creates novel opportunities for circRNA

circVec substantially outperforms the expression level and durability of mRNA-based systems in cells

Prolonged durability

→Enhanced therapeutics

"Due to its significant advantages, circRNA systems can be expected to replace mRNA-based expression for DNA format therapeutics in the future – just as synthetic circRNA can be expected to replace current mRNA formats"

Dr. Alex Wesselhoeft Scientific founder oRNA Therapeutics

Increased expression level circVec 2.1 vs. mVec (mRNA) luciferase reporter expression; in vitro

New and enhanced circVec 3.0 in current testing

circVec 2.1 achieves > 6 month expression durability on one single injection in immuno-competent mouse muscle

10

Low dose example animal

Bioinformatic analysis of circVec 2.1 in vivo data indicates over 70 times increased half-life of circRNA vs. mRNA

Inferred in vivo RNA half-life (hours), bioinformatic modelling Inferred in vivo peak expression (days) 8h 610h 2.3d 38d Immuno-compromised mice Immuno-competent mice >70x longer in vivo half-life vs. mRNA Peak expression 135h cRNA after >1 month 9h mRNA 233h 9h in vitro ½-life 135h cRNA 9h mRNA in vitro ½-life 11

circVec 2.1 dose response in vivo - strongest advantage vs. mRNA observed at low dose, high therapeutic relevance

Absolute expression (luminescence)

circVec 2.1 vs. mRNA pDNA vector expression

Relative expression (luminescence)

-fold change circVec 2.1 vs. mRNA expression

LNP-formulated circVec 2.1 accumulates in spleen with >12 week durability, minimizes liver expression

LNP-mVec (mRNA), luminescence Systemic I.V. delivery, single dose on Day 0 LNP-circVec 2.1 (circRNA), luminescence Systemic I.V. delivery, single dose on Day 0

circRNA durability adv. does not apply in liver

The circVec platform can be deployed in multiple disease areas and therapeutic settings

Target, therapeutic format and disease to be prioritized based on data from ongoing in vivo program

circVec is a potentially disruptive novel expression technology for AAV gene therapy

AAV protein expression, in vitro f-Luc

circVec-AAV feasibility validated, testing and optimization of constructs ongoing

circVec ´Remove-&-Replace´ gene therapy concept, AATD case example

1.5

Circio is the leader in DNA-format circular mRNA, take-home messages:

Due to its significant advantages, circRNA systems can be expected to replace mRNAbased expression for DNA format therapeutics in the future – just as synthetic circRNA " can be expected to replace current mRNA formats "

Dr. Alex Wesselhoeft

18 Scientific founder oRNA Therapeutics