Arnatar Therapeutics Emerges from Stealth and Announces Receipt of FDA Orphan Drug and Rare Pediatric Disease Designations for ART4

$52M Series A raised in 2024, led by Eight Roads and 3E Bioventures

SAN DIEGO, Aug. 25, 2025 (GLOBE NEWSWIRE) -- Arnatar Therapeutics, a biotechnology company pioneering RNA-based therapies for severe and underserved diseases, emerges from stealth today and announces that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation and Rare Pediatric Disease Designation to ART4, the company’s up-regulating antisense oligonucleotide (ASO) therapeutic candidate for the treatment of Alagille Syndrome (ALGS).

“We are excited to emerge from stealth with a strong scientific foundation and the resources to advance our pipeline of groundbreaking RNA therapeutics. Our $52 million Series A financing enables us to advance Arnatar’s DARGER™ platform and pipeline of RNA therapeutics, which uniquely combine best-in-class siRNA with first-in-class upregulating ASOs to deliver transformative medicines for cardiometabolic, liver, CNS, and kidney diseases.

Receiving both Orphan Drug and Rare Pediatric Disease designations from the FDA highlights the potential of ART4 to address a significant unmet need and meaningfully alter the course of this devastating disease,” said Xuehai Liang, Chief Executive Officer of Arnatar Therapeutics. “Our approach is designed to target the underlying genetic deficiency to restore bile duct function and prevent the severe complications, including liver damage, that children with ALGS often face. We remain committed to advancing ART4 into the clinic as rapidly as possible to bring this potentially transformative therapy to patients and families who currently have no curative treatment options.”

ART4 is designed to address the root cause of ALGS by leveraging Arnatar’s proprietary ACT-UP1 platform to upregulate endogenous JAG1 protein expression, and is administered subcutaneously and is designed for once-monthly dosing. In preclinical studies, ART4 significantly increased JAG1 protein levels, restored bile duct development, and reduced markers of liver injury — including bile acids and ALT — in a validated ALGS disease mouse model. The treatment was well-tolerated in both adult and newborn animals.

ALGS is a rare, life-threatening, multisystem genetic disorder that primarily affects the liver, heart, and vasculature. Approximately 95% of ALGS cases are caused by haploinsufficient mutations in the Jagged-1 (JAG1) gene, leading to insufficient JAG1 protein levels and impaired liver bile duct development. As a result, patients experience toxic bile acid accumulation, progressive liver damage, and systemic complications that often begin early in life.

The U.S. Food and Drug Administration’s Orphan Drug Designation program is intended to encourage the development of therapies for rare diseases, defined as conditions affecting fewer than 200,000 people in the United States. The designation provides a range of benefits including seven years of market exclusivity upon approval, eligibility for tax credits on qualified clinical trials, waiver of FDA user fees, and access to federal grants to support clinical development.

The Rare Pediatric Disease Designation may allow Arnatar to receive a Priority Review Voucher (PRV) upon ART4’s potential marketing approval, which could be used to expedite the review of another drug candidate.

Arnatar raised a $52M Series A round that closed in 2024 and was led by Eight Roads and 3E Bioventures. F-Prime Capital, along with Zhuhai Huajin Capital, Legend Star, Transfar Capital, New Alliance Capital, Yijing Capital, Gaorong Ventures, Jifeng Ventures and Hongsheng Capital also participated in the financing. The company was founded in 2022 and received seed financing from Apricot Capital.

About Arnatar Therapeutics

Arnatar Therapeutics is a clinical-stage biotechnology company redefining the possibilities of RNA medicine. With its proprietary DARGER™ platform, Arnatar uniquely integrates best-in-class siRNA gene silencing with first-in-class antisense oligonucleotides (ASOs) that upregulate protein expression. This dual-modality platform empowers Arnatar to develop RNA medicines that either silence harmful disease drivers through siRNA or restore essential protein function through up-regulating ASOs, opening new therapeutic possibilities for previously untreatable conditions. The company’s pipeline spans across cardiometabolic, liver, kidney, and central nervous system diseases, targeting areas of high unmet medical need. Founded by leaders in RNA therapeutics and backed by leading biotech investors, Arnatar is committed to transforming RNA innovation into life-changing, programmable medicines for patients worldwide.

Contacts

Chris Nardo
LifeSci Advisors, LLC
cnardo@lifesciadvisors.com
646-517-2499

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