New in vivo data show a circular RNA platform can deliver up to a 50-fold increase in gene expression in the eye compared with conventional mRNA-based AAV approaches.
Circio has announced new in vivo data for its circular RNA expression platform, circVec, which has, for the first time, shown up to 50-fold enhanced gene expression in the eye compared with conventional mRNA-based AAV approaches.
The biotechnology company, which develops circular RNA technology for gene and cell therapy, said the findings make ophthalmology a new area of exploration for circVec-based gene therapy development.
Strongest improvement seen in ocular delivery
According to the company, local delivery of AAV-circVec 4.0 to the eye produced the most substantial improvement over mRNA-based AAV observed to date. In vivo testing showed up to a 50-fold increase in gene expression.
Rising industry interest in ophthalmology has contributed to Circio’s decision to prioritise eye disease as a development focus.
The data also indicated that AAV-circVec maintained a 10-fold performance advantage over conventional AAV even when administered at a 90 percent reduced dose level. The company believes this could translate into improved safety profiles and lower manufacturing costs.
Rising industry interest in ophthalmology has contributed to Circio’s decision to prioritise eye disease as a development focus. The company pointed to several recent strategic transactions by major pharmaceutical groups and specialist investors as evidence of growing momentum in the sector.
Circio said its circular RNA-based gene expression system has the potential to substantially increase potency while reducing toxicity and cost in AAV-based therapeutics targeting genetic and degenerative eye diseases with significant unmet medical need.
Heart data reproduced and validated
In parallel with its ophthalmology work, Circio has continued to expand its data package for AAV-circVec 3.2 and 4.0 in cardiac applications. The previously reported 40-fold increase in gene expression in heart tissue has now been reproduced in new experiments.
Molecular analysis of ex vivo tissue samples further showed that 80 percent of heart cells were positive for circVec expression following systemic AAV delivery at low doses. Additional RNA and AAV DNA copy number measurements confirmed that the enhanced expression is directly linked to the greater durability of circular RNA compared with mRNA, supporting the core scientific rationale of the circVec platform.
“Circio is undertaking broad characterisation and optimisation of the circVec technology, and the strong AAV gene expression performance in heart has now been exceeded by in vivo data in eye,” said Dr Thomas B Hansen, CTO of Circio. “The expanding data package clearly demonstrates the potential of the circVec platform to improve efficacy, safety and accessibility of AAV gene therapy. Next, our focus will be to apply these promising technical findings in disease-relevant contexts, with the aim to develop therapeutic AAV-circVec constructs to treat heart and eye disease with high unmet medical needs.”
Oversubscribed financing supports expansion
Earlier in the first quarter of 2026, Circio completed a financing first announced in December 2025, raising NOK 68.6 million, approximately USD 7 million, through a 50 percent oversubscribed rights issue and parallel private placements.
The company said the funds will accelerate circVec research and development over the next 12 months.
The company said the funds will accelerate circVec research and development over the next 12 months. An associated warrant structure, exercisable in June 2026, could provide additional capital and extend the company’s financing runway into the second half of 2027.
“The robust technological foundation, unique expertise and strong in vivo data, combined with the recently announced R&D collaboration with a global pharma company, were key elements to achieve a highly successful fundraising,” said Dr Erik Digman Wiklund, CEO of Circio. “With strong support from existing shareholders, we were able to raise substantially more funds than originally targeted. The capital infusion will enable Circio to expand the R&D team in Stockholm, accelerate circVec platform development and deliver important scientific milestones to generate new business development opportunities and support Circio’s continued growth.”
