Sobi, a biopharmaceutical company developing treatments for rare diseases, announced plans to acquire Arthrosi Therapeutics, a clinical-stage biotechnology company developing a potentially best-in-class treatment for progressive and tophaceous gout, in a deal worth up to $1.5 billion on December 13th, 2025. According to a company press release, Sobi will pay approximately 950 million upfront to acquire Arthrosi, with an additional $550 contingent on various clinical, regulatory, and sales milestones.

Arthrosi’s lead candidate is pozdeutinurad, an investigational, once-daily oral URAT1 inhibitor designed to reduce serum urate levels, flares, and tophi in patients with gout. According to a clinical trial summary published on Arthrosi’s site, patients treated with pozdeutinurad in a Phase IIa study had a sustained reduction of serum uric acid (<5 mg/dL in 93% of patients) and demonstrated “high potential to reduce flares and resolve tophi.” The treatment is currently being studied in two Phase III studies, REDUCE 1 and REDUCE 2, with pivotal results expected in 2026.

“The acquisition of Arthrosi allows us to expand our gout pipeline with a highly differentiated new asset,” said Guido Oelkers, President and CEO, Sobi, in the release. “Pozdeutinurad has the potential to become the therapy of choice for patients who have progressive gout with persistent and unresolved symptoms despite first-line therapy. The product has the potential to materially accelerate our growth until the mid 2030s, and beyond. We welcome all members of the talented Arthrosi team and are looking forward to working closely together to be able to offer this therapy to patients as soon as possible.”

“We are thrilled to join forces with Sobi and look forward to working together to ensure a seamless transition as they advance pozdeutinurad towards pivotal data and potential regulatory filings,” said Litain Yeh, Ph.D., Founder and CEO, Arthrosi Therapeutics, in the release. “We believe that Sobi’s global expertise in commercialisation will accelerate our shared mission to deliver pozdeutinurad’s potentially transformative benefits for individuals living with gout.”