Swedish biopharmaceutical company Swedish Orphan Biovitrum AB said Monday it has struck a deal to buy Arthrosi Therapeutics Inc., a U.S.-based gout specialist, in a transaction valued at up to $1.5 billion, positioning the company for a long-term expansion in gout treatments.

Deal Designed to Bolster Gout Portfolio

Known as Sobi and listed on the Nasdaq Stockholm, the company said the acquisition will deepen and diversify its existing gout portfolio, anchoring future growth in a late-stage drug candidate with blockbuster potential.

Under the terms of the agreement, Sobi will pay $950 million in cash at closing, followed by up to $550 million in additional payments contingent on Arthrosi meeting undisclosed clinical, regulatory and commercial milestones.

A Next-Generation Gout Therapy at the Core

Arthrosi, a privately held biotechnology firm based in San Diego, California, is developing pozdeutinurad, a next-generation therapy aimed at patients with progressive and chronic gout. The drug has completed Phase 2 trials, delivering promising results, and Phase 3 data is expected in 2026, the companies said.

“The acquisition of Arthrosi allows us to expand our gout pipeline with a highly differentiated new asset,” said Guido Oelkers, Sobi’s chief executive. “Pozdeutinurad has the potential to become the therapy of choice for patients.”

Oelkers added that the transaction could help propel Sobi’s growth trajectory well beyond 2035, underscoring the strategic importance of the deal.

Financing and Advisors Lined Up

Sobi said it plans to finance the upfront payment primarily through debt provided by Handelsbanken and Danske Bank. The transaction is expected to close by June 2026, subject to customary closing conditions.

McDermott Will & Schulte is serving as legal adviser to Sobi, while Barclays Bank PLC is acting as financial adviser. Counsel information for Arthrosi was not immediately available.

Arthrosi most recently raised $153 million in a Series E funding round in October to advance its clinical program—capital that now sets the stage for a high-stakes exit as Sobi moves to secure its next flagship therapy.