Rigerna Therapeutics and Hisun Pharmaceutical Ink Up to RMB 990 Million siRNA Platform and Pipeline Licensing Deal

Suzhou, China—When Suzhou Rigerna Therapeutics announced a collaboration with Zhejiang Hisun Pharmaceutical Co. Ltd. on October 28, the deal sent a clear signal about the growing commercial appetite for China's small nucleic acid drug platforms.

The partnership, valued at up to RMB 990 million (approximately $137 million), gives Hisun access to Rigerna's proprietary liver-targeted GalNAc delivery technology and an early-stage siRNA candidate called RGN6669. The structure includes an upfront payment, milestone-based compensation, and potential revenue shares from sublicensing and commercial sales.

For Rigerna, a biotech founded in 2022, the deal represents a validation of its core technology platforms—RIHOST for sequence design, RICMO for chemical modification, and LICOD for in vivo delivery. The company has built these platforms with global intellectual property protection, claiming advantages over international GalNAc technologies in delivery efficiency, synthesis, and cost.

Two-Part Structure

The collaboration unfolds in two distinct parts. First, Rigerna grants Hisun exclusive, sublicensable rights to use its siRNA technology platforms for developing drugs against specified targets. Under this arrangement, Rigerna retains ownership of the platform intellectual property, while Hisun owns the intellectual property for drugs developed against those targets. Hisun will lead and fund all product development.

Second, the companies are partnering on RGN6669, a liver-targeted siRNA product in early preclinical stage. Following the agreement's effective date, both parties will jointly own the intellectual property. Hisun receives exclusive, sublicensable rights to develop and commercialize the candidate, bearing all subsequent research, development, and commercialization costs.

The agreement also allows Hisun to add new collaboration targets in the future, subject to Rigerna's written consent.

Beyond Liver Targeting

While liver-targeted GalNAc conjugate delivery forms the foundation of Rigerna's platform, the company has also developed receptor-recognition-based active targeting technologies for extrahepatic tissues and cells, including kidney and adipose tissue. These technologies are now being translated into a pipeline of investigational candidates.

Rigerna's core technology platforms have secured patent protection across multiple countries and regions worldwide, according to the company.

Clinical Validation

The collaboration comes as Rigerna demonstrates clinical traction with its lead asset. RGN3919, the company's first-in-class pipeline candidate, has achieved positive results in Phase II clinical trials for IgA nephropathy. The company recently presented interim data from a global randomized, double-blind, controlled Phase II study at the ASN 2026 conference in the United States—marking what Rigerna describes as the world's first such mid-stage study for the treatment.

Rigerna has also established a track record of industry partnerships. The company previously entered a co-development agreement with CR Double Crane Pharmaceutical for a siRNA drug based on its liver-targeted delivery and chemical modification technologies. That collaboration is reportedly progressing smoothly and has achieved milestone progress.

For Hisun Pharmaceutical, the deal provides access to cutting-edge siRNA platform technology and an early-stage pipeline candidate, bolstering its position in the competitive nucleic acid therapeutics space. The Zhejiang-based pharmaceutical company gains exclusive development rights while leveraging Rigerna's proprietary delivery innovations.

The partnership underscores a broader trend in China's biopharmaceutical sector: platform technology companies partnering with established pharmaceutical players to accelerate drug development while sharing risks and rewards. As siRNA therapeutics continue gaining momentum globally—with multiple approved drugs and an expanding clinical pipeline—collaborations like this one position both companies to compete in what analysts see as a high-growth segment of the biopharmaceutical market.