Arnatar is developing ART4, an antisense oligonucleotide that ups the expression of its target protein to treat a rare disease called Alagille syndrome.
Arnatar Therapeutics entered the biopharma arena on Monday to advance a potentially first-in-class RNA-based therapy that aims to increase the expression of a particular protein rather than silence it to treat the rare genetic disease Alagille syndrome.
The California-based startup will begin its journey with $52 million collected in a series A funding round closed in 2024. Arnatar said it will use the capital primarily to develop ART4, an investigational antisense oligonucleotide that targets and upregulates the JAG1 protein.
Arnatar on Monday also revealed that the FDA has granted ART4 its orphan drug and rare pediatric disease designations.
Afflicting one in every 70,000 newborns, Alagille syndrome is a serious chronic disorder that affects multiple organ systems, including the heart and the liver. According to Arnatar’s website, some 95% of Alagille cases are caused by mutations in the JAG1 gene, leading to insufficient levels of the protein. This compromises the development of the bile duct and, in turn, leads to liver damage.
ART4 addresses this underlying disease pathway by inducing production of the JAG1 protein. Preclinical studies have validated this mechanism, demonstrating that the investigational therapy not only boosts protein levels but also helps restore the development of the bile duct and reduce markers of liver damage. ART4 is currently undergoing IND-enabling studies.
Aside from ART4, Arnatar is also developing ART1, an investigational siRNA therapy that takes the more typical approach of silencing its target, this time the AGT protein, which plays a key role in maintaining blood pressure homeostasis. ART1 is in early clinical development for cardiovascular disease.
Arnatar is backed by Eight Roads and 3E Bioventures, which led its series A push last year. Other funders, such as F-Prime Capital, New Alliance Capital and Jifeng Ventures participated in the funding round.
With its debut on Monday, Arnatar follows in the footsteps of other biotech startups that have launched this year. Dispatch Bio raised $216 million last month to support its mission of developing CAR T therapies as a universal approach to solid tumors. The biotech was founded by ARCH Venture Partners and is backed by big names, including Bristol Myers Squibb and Stanford University.
A few days later, BMS put another entity on the market with funding support from Bain Capital. The new startup, which has yet to be named, received five immunology assets from the pharma and $300 million from the investment firm, with a mission to develop these molecules for autoimmune disorders.
