San Diego-based biotechnology company Arthrosi Therapeutics has secured $153 million in Series E funding to advance its flagship gout therapy pozdeutinurad (AR882) through pivotal Phase III trials. The financing round, led by Prime Eight Capital with participation from HighLight Capital, CR Biotech, HM Venture Partners, ReliantTech and existing shareholders, positions the company to potentially transform treatment for a condition affecting 56 million people worldwide.
Addressing Critical Unmet Need in Gout Treatment
Gout represents a significant therapeutic challenge as an inflammatory form of arthritis that severely impacts patients' functionality, quality of life and mobility. The condition is caused by crystallization of uric acid in soft tissues and joints, leading to characteristic flare-ups and persistent symptoms. Critically, 90% of gout cases result from underexcretion of uric acid, creating high serum urate (sUA) levels and subsequent crystal deposition.
Current treatment options remain limited, with allopurinol serving as the standard first-line therapy to lower uric acid levels. However, this approach doesn't work for all patients, leaving few alternatives beyond Amgen's infusible drug Krystexxa for refractory cases.
Next-Generation URAT1 Inhibition Strategy
Arthrosi's pozdeutinurad represents what the company describes as a "highly potent and selective next generation" URAT1 inhibitor that is "potentially best-in-class." The drug targets URAT1, a key transporter protein that regulates uric acid levels in the body.
This approach builds on lessons learned from earlier URAT1 inhibitors. AstraZeneca's Zurampic, approved in 2015, was withdrawn from the market four years later due to associations with kidney damage. Arthrosi's therapy aims to overcome these safety limitations while maintaining therapeutic efficacy.
Pivotal Phase III Program Underway
The funding will support Arthrosi's comprehensive Phase III development program, consisting of two randomized, placebo-controlled, double-blind, twelve-month studies called REDUCE 1 and REDUCE 2. Both trials are designed to assess pozdeutinurad in treating gout and tophaceous gout, with enrollment already completed.
The primary endpoint focuses on the therapy's potential to lower serum urate levels in patients. Secondary objectives include monitoring the reduction of gout flares and tophi over the treatment course. Arthrosi anticipates releasing pivotal data from these studies in the second quarter of 2026.
Strong Clinical Foundation
Pozdeutinurad has demonstrated encouraging results in earlier-stage development. The therapy showed promise in terms of efficacy and safety in Phase II studies when compared against standard of care. Notably, the drug achieved complete tophi resolution in a Phase IIb trial, suggesting potential for addressing the chronic manifestations of gout.
"We are delighted to have the continued support of an experienced and deeply committed group of investors," stated Arthrosi CEO and founder Litain Yeh. "Arthrosi continues to make rapid progress on our mission to transform the treatment landscape for gout and tophaceous gout, an area with pressing unmet need. The commitment from both new and existing investors provides further validation for pozdeutinurad and the robust clinical data package we have generated to date."
