On December 13, 2025, Sobi announced it has entered into a definitive agreement to acquire Arthrosi Therapeutics, Inc., a private late-stage biotechnology company focused on developing a next-generation treatment for gout. Sobi will pay $950 million upfront in cash and up to $550 million in cash in clinical, regulatory and sales milestones. Wilson Sonsini Goodrich & Rosati represented Arthrosi Therapeutics on patent matters related to the acquisition.

The acquisition strengthens Sobi’s gout franchise by adding pozdeutinurad (AR882), an investigational next-generation, once-daily oral URAT1 inhibitor currently being evaluated in two fully recruited global Phase 3 clinical studies for the potential management of progressive and tophaceous gout and expected to read out in 2026.

The Wilson Sonsini team that advised Arthrosi Therapeutics on the transaction included Nima Zargari, Jim Malecha, and Michael Hostetler.

For more information, please see Sobi’s news release. Additional coverage can be found on Reuters, Investing.com, Investors in Healthcare, and The Pharma Letter (subscription required).