Circio Holding ASA

Investor Presentation • Mar 5, 2025

CircVec – A novel Payload Expression Platform Based on Circular RNA Biogenesis: Features and Opportunities

Biologics World Nordics Stockholm, Sweden March 5th, 2025

1 circRNA introduction

• 1. circVec platform
• 1. circVec lead program
• 1. Summary & team

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

Human circRNA was first described by Circio scientists

30 September 2011 1,000 citations January 2025

These advantages drive high deal activity in circular RNA, competitors all focus on synthetic IVT circular RNA

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

Circio is being recognized internationally as a leader with unique technology in the circRNA field

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• 1. circVec lead program
• 1. Summary & team

The starting point for the circVec construct is based on nature ´s best design

Expression of human endogenous circRNA NGS analysis of 300+ RNAseq datasets

effective loci in the human genome → circVec 1st generation

Optimizing nature´s best design to build circVec 3.0

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

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

13

Low dose example animal

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

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 15

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

3D bioluminescence imaging + CT confirm spleen-specific circVec expression

17

Ongoing in vivo experiment, example animal

circVec lead program

1. Summary & team

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 circRNA for genetic medicine, take-home messages:

New circVec 3.0 generation expected to further strengthen and solidify advantages → in vivo testing ongoing

Applicable for any AAV and DNA format therapeutics

Broad opportunities for future partnering/licensing