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SAN DIEGO, CA, Sep. 8, 2025 -- Arnatar Therapeutics, a biotechnology company pioneering RNA-based therapies for severe and underserved diseases, today announced the publication of foundational patent applications covering ACT-UP1, a novel class of antisense compounds designed to upregulate protein expression. These applications cover ACT-UP1’s unique mechanism of action, composition, and broad therapeutic applications.

“Publication of these applications is an important milestone for Arnatar,” said Xuehai Liang, Ph.D., Chief ExecutiveOfficer of Arnatar Therapeutics. “ACT-UP1 is a novel platform with the potential to transform the treatment of diseases caused by haploinsufficiency and protein-deficiency.”

ACT-UP1 compounds represent a first-in-class approach to increase protein expression by hybridizing directly to target mRNAs and recruiting translation-related proteins to enhance translation. Unlike other strategies, ACT-UP1:

• Does not depend on inhibitory mRNA elements or co-delivery of exogenous proteins

• Enables upregulation across a broader range of genes

• Can theoretically boost any protein of interest

The compounds are short, chemically modified oligonucleotides that efficiently enter cells, demonstrate increased durability, and support less frequent dosing. Preclinical data demonstrated protein expression increases of up to approximately 130-200%.

Arnatar is advancing ACT-UP1 in multiple therapeutic areas, including Alagille Syndrome (ALGS) and AutosomalDominant Polycystic Kidney Disease (ADPKD).