Lesinurad

There’s a contest brewing between two San Diego biotechs looking to create the next gout medicine. Arthrosi Therapeutics uncorked a $153 million Series E on Wednesday to complete two Phase 3 trials of its experimental drug called pozdeutinurad. The studies are slated to read out in the second quarter of 2026, the biotech said. Prime Eight Capital led the Series E. CR Biotech, HighLight Capital and others also took part in the round. Arthrosi was founded in 2018. The megaround comes two weeks after Crystalys Therapeutics emerged with a $205 million Series A . Crystalys recently began two Phase 3 gout trials of its asset, named dotinurad, and anticipates data around the end of 2027. While Crystalys’ dotinurad is further behind in the US, the gout drug is already approved in Japan, China and a couple other countries in Asia. The Novo Holdings-backed biotech is seeking to get the treatment approved in the US and Europe. Both Arthrosi and Crystalys are working on URAT1 inhibitors to reduce serum urate levels in people with gout. High levels of uric acid in the blood can lead to urate crystals forming in the joints, especially in the big toe, with patients experiencing intense pain and inflammation in that area. The CEOs at Crystalys and Arthrosi know each other from their days at Ardea Biosciences and have experience with URAT1 inhibitors. Crystalys CEO James Mackay led AstraZeneca’s Ardea, which got approval of the oral drug Zurampic. The gout treatment was eventually discontinued . Arthrosi CEO Litain Yeh was a VP of translational sciences at Ardea.

Arthrosi Therapeutics has secured a nine-figure funding round to accelerate development of a new kind of gout medicine.The San Diego-based biotechnology startup on Wednesday revealed it has closed $153 million in a Series E financing, which was led by Prime Eight Capital and involved a handful of other venture firms and existing investors. Arthrosi will use the funds to advance what its billing as a potential step forward in care for gout, a form of arthritis triggered by a toxic accumulation of uric acid in the body. The condition, which most commonly impacts the big toe joint, is estimated to affect some 56 million people around the world and is known for the gout attacks, or sudden flare-ups of joint pain it causes.Gout has long been typically treated with a drug called allopurinol that lowers levels of uric acid in the body. But that treatment doesnt work for everyone, and there are limited options behind it, among them an infusibledrug called Krystexxa thats now owned by Amgen. Arthrosi is among those working on an alternative, a prospect its codenamed pozdeutinurad, or AR882.Arthrosis drug is a newer twist on a kind of medicine that works by blocking a key transporter protein called URAT1, which regulates uric acid levels. An earlier URAT1 inhibitor, known as Zurampic and sold by AstraZeneca, was approved in 2015. But the drug was associated with kidney damage and pulled from the market four years later.Arthrosi describes its drug, by comparison, as a highly potent and selective next generation URAT1 inhibitor thats potentially best-in-class. Its already completed mid-stage testing, and two Phase 3 trials are fully enrolled, with results expected in the second quarter of 2026.The company isnt alone. Dotinurad, a drug discovered by Japans Fuji Yakuhin and approved in the country in 2020, is also a more specific URAT1 blocker. Its now marketed in multiple Asian countries and, last year, its U.S. and European rights were acquired by startup Crystalys Therapeutics, which launched with a nine-figure round of its own last month. Crystalys intends to start a global Phase 3 trial as well. Multiple China-based drug developers have newer URAT1 inhibitors in testing, too. '