Circio Holding ASA, a biotechnology company developing circular RNA technology for nucleic acid medicine, has presented strengthened in vivo data for its circVec-AAV expression system.
Circio´s CTO Thomas B Hansen showcased the latest circVec generation 3.2. This novel circVec design significantly enhances gene expression from AAV vectors in vivo. The encouraging circVec-AAV heart data presented in May 2025 has now been validated in a larger in vivo repeat experiment and further augmented by circVec 3.2, which delivers up to 40 times protein expression level advantage compared with conventional mRNA-AAV. Circio is now incorporating and testing circVec 3.2 in its portfolio of AAV vectors.
Circio is characterising the performance of circVec-AAVs in several other tissues, and has identified the eye as an organ showing 15 times expression advantage compared to benchmark AAVs. Following successful pilot experiments, broader in vivo testing is currently ongoing. Circio expects to report this data during the second half of 2025.
“Circio has now completed substantial characterisation, engineering and optimisation of its circVec expression system for gene therapy. These results make it evident that circular RNA-based expression has the potential to substantially improve the therapeutic potency of AAV vectors in a tissue-specific manner. This creates multiple distinct development opportunities for the circVec platform,” Hansen said.
“A major challenge of conventional mRNA-based AAV gene therapy is the need for extremely high dose levels. This can cause severe toxicity in patients and drives up manufacturing cost and complexity. Our current data package suggests that switching to circVec-based expression may enable 10-fold, or more, dose reduction, which would be a major breakthrough for the AAV gene therapy field.”
During the first half of 2025, Circio has continued to implement tight cost controls with a lean organisational set-up, strictly prioritizing R&D activities that can deliver near-term technology validation and business development opportunities. The extension of the financing commitment by Atlas Capital Markets secures funding until the end of 2025. The company is exploring multiple alternatives to secure new capital, strengthen the shareholder base and thereby minimise the reliance on the convertible bond facility.
“The technical achievements of Circio´s research team continue to impress, especially given our lean, cost-efficient set-up,” said Lubor Gaal, CFO of Circio.
“Importantly, the latest circVec-AAV in vivo results confirm that the robust circVec advantage applies broadly. The data package now includes several tissues, additional AAV capsids and multiple genetic promoters driving expression. These results broaden and strengthen Circio’s data package, and derisks the technology for potential partners and investors. Our aim is to leverage these new data to establish R&D collaborations with AAV expert companies and validate the performance of the circVec platform in their systems. We already have ongoing dialogues and aim to enter multiple such partnerships during 2025-26.”
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