Swedish orphan-drug specialist Sobi has agreed to acquire Arthrosi, a privately held biotech focused on next-generation gout therapies, in a move that materially expands Sobi’s inflammation and rheumatology pipeline and positions the company for longer-term growth beyond rare hematology.
The deal brings Arthrosi’s lead clinical-stage gout asset into Sobi’s portfolio, strengthening its exposure to one of the largest and underserved markets, increasingly viewed as a chronic inflammatory disease rather than an episodic condition. Sobi characterized the transaction as strategically aligned with its ambition to build scale in specialty and rare inflammation.
Sobi will acquire Arthrosi for SEK 9.1 billion ($950 million) in upfront cash, marking one of the largest transactions in the gout market in recent years. The deal also includes potential milestone payments of up to SEK 5.3 billion ($550 million) tied to clinical progress, regulatory approvals, and commercial performance, bringing the total deal value to approximately SEK 14.4 billion ($1.5 billion) if all milestones are achieved.
The structure reflects Sobi’s confidence in Arthrosi’s lead gout asset while spreading development and execution risk across value-inflection points. By committing significant upfront capital, Sobi signals that gout is not a peripheral adjacency but a core pillar of its long-term inflammation strategy, with expectations of meaningful commercial scale rather than niche uptake.
Arthrosi’s program is designed to address persistent hyperuricemia and inflammatory flares in patients who remain inadequately controlled on standard urate-lowering therapies. While existing gout drugs are effective for many patients, real-world adherence issues, contraindications, and flare risk during initiation continue to leave a meaningful treatment gap, particularly in patients with advanced disease or comorbidities.
The acquisition complements its existing inflammation footprint while offering a pathway into a high-prevalence indication with chronic-use potential. Unlike ultra-rare disorders, gout provides commercial leverage through broader prescriber reach, longer treatment duration, and the opportunity to build integrated care strategies across rheumatology and internal medicine.
Operationally, Sobi plans to advance Arthrosi’s lead asset through late-stage development using its established global clinical, regulatory, and commercialization infrastructure. The company also gains Arthrosi’s discovery capabilities, which management says could support follow-on assets in gout and adjacent inflammatory conditions.