Arnatar Therapeutics

Founded in 2022 and backed initially by Apricot Capital, the company closed a $52 million Series A round in 2024 led by Eight Roads Capital and 3E Bioventures, with participation from F-Prime Capital and others.

Its proprietary DARGER™ platform combines two strategies: siRNA-mediated gene silencing and ACT‑UP1 antisense oligonucleotides (ASOs) that upregulate protein expression. This dual-modality approach allows Arnatar to tackle both excess and deficient protein activity across key therapeutic areas, including cardiovascular/metabolic disease, liver disorders, CNS conditions, and kidney disease 

Arnatar’s lead program, ART4, is an ASO designed to raise JAG1 protein levels to treat Alagille Syndrome (ALGS), a rare pediatric liver and vascular disorder. The therapy is administered subcutaneously on a once-monthly schedule. In preclinical models, ART4 restored bile duct development and reduced markers of liver injury, with positive safety findings in both adult and newborn animals .

In August 2025, the U.S. Food and Drug Administration granted ART4 both Orphan Drug and Rare Pediatric Disease designations—recognitions that may enable priority regulatory review and market exclusivity.