• Circio´s proprietary circVec circular RNA platform has demonstrated 40-fold enhanced gene expression from AAV vectors in heart
• AaviGen´s proprietary AAV capsids are designed for targeted and specific delivery to heart cardiomyocytes
• The objective is to evaluate the potential synergy of Circio´s and AaviGen’s complementary technologies in developing next generation AAVs specifically for cardiac applications
• If successful, the collaboration may enable significant dose reduction and tissue targeting, thereby addressing key challenges for AAV-based gene therapy

Oslo, Norway, and Heidelberg, Germany 27 May 2026 – Circio Holding ASA (OSE: CRNA), a biotechnology company developing novel circular RNA expression technology for gene and cell therapy, and AaviGen Gmbh a biotechnology company focused on precision gene therapies for human cardiac diseases, today jointly announce a research collaboration to develop circVec-enhanced AAV vectors specifically engineered for targeted, low dose heart gene therapy.

By integrating these complementary technologies, the collaboration seeks to pioneer the next generation of AAV gene therapy candidates. The focus is on addressing genetic and chronic heart conditions through therapies that can be administered at low therapeutic doses, ensuring high and confined expression in heart while minimizing off-target effects. This initiative represents a significant step forward in the field of gene therapy, potentially transforming treatment paradigms for patients with heart-related indications.

“The future clinical success of cardiac gene therapies will be determined by precision elements that ensure both efficacy and safety,” said Dr. Martin Busch, COO of AaviGen. “AaviGen’s human heart-derived next-generation cardiac-targeted vector technology enables precision delivery of therapeutic genes and lays the groundwork for the targeted integration of components tailored to specific indications, with Circio’s innovative expression-enhancing platform being a key element. The combination of AaviGen’s targeted capsids with the circVec platform could therefore open the door to a new level of efficiency and safety — an opportunity we are very excited to explore together with the Circio team.”

The collaboration will involve three stages: 1) Production of novel AAVs combining the proprietary heart-targeted capsids from AaviGen with the circVec expression cassette from Circio, 2) Testing and characterization of the novel AAVs in vitro, and 3) Confirmation and validation of AAV performance in vivo with focus on AAV biodistribution and gene expression profiles between different design combinations.

“The novel targeted AAV capsids engineered by AaviGen have the ability to very specifically reach cells in the heart in an efficient and safe manner,” said Dr. Victor Levitsky, CSO of Circio. “This collaboration is an excellent opportunity to evaluate whether enhanced circVec expression can act synergistically with heart-targeted capsids. The combination of our technologies has the potential to maximize on-target gene expression and minimize off-target delivery, resulting in substantial dose reduction and an improved toxicity profile. This can make AAV-based gene therapy accessible for patients with severe inherited heart diseases as well as address large and growing medical need in chronic heart failure.”

About AaviGen
AaviGen was founded on the insight that successful cardiac gene therapy depends on the optimized delivery of genetic therapeutics to the diseased heart. Its human-to-human, cardiac-targeted AAV vector technology sets new standards for precision, efficacy, and safety in the treatment of both acquired and inherited heart diseases. AaviGen’s scientific approach is supported by numerous peer-reviewed publications and builds on the founders’ strong track record of scientific innovation in the diagnosis and treatment of heart disease, including the development of gene therapy medicines. For more information, please visit: www.aavigen.com.

About Circio
Circio Holding ASA is a biotechnology company developing novel circular RNA expression technology for gene and cell therapy.

Circio has established a unique circular RNA (circRNA) vector expression technology for next generation RNA, DNA and viral therapeutics. The proprietary circVec platform is based on a modular genetic construct designed for efficient biogenesis of multifunctional circRNA inside target cells. The circVec platform has applications in multiple therapeutic settings, including genetic medicine, cell therapy and chronic disease. It has demonstrated 75-fold increased RNA half-life and up to 50-fold enhanced protein expression vs. conventional mRNA-based viral and non-viral vector systems, with the potential to become a new gold-standard gene expression technology. The circVec R&D activities are being conducted by the wholly owned subsidiary Circio AB in Stockholm, Sweden.