Arthrosi secures $153M series E to fund late-stage gout drug development

Arthrosi Therapeutics raised $153 million in a series E round to fund two phase 3 trials of its gout drug candidate, pozdeutinurad, with key data expected in 2026. The company raised $75M in a 2023 series D; this new round brings its total to over $228M.

Why it matters: Gout affects millions globally, and Arthrosi is targeting a longstanding treatment challenge with a next-gen URAT1 inhibitor, backed by big investor confidence despite past commercial setbacks in this drug class.

Backstory: URAT1 inhibitors have a long history in gout treatment. The first, probenecid, was approved in 1951 but caused side effects due to its broad action. Newer drugs aimed for more selective URAT1 inhibition to reduce those risks. AstraZeneca’s Zurampic, approved in 2015 after a $1.3B acquisition, ultimately failed commercially due to safety issues, earning a boxed warning and being withdrawn by 2018. Despite that, the promise of safer URAT1 inhibitors has kept the race alive.

Big picture: Despite past commercial failures like AstraZeneca’s Zurampic, investor and industry interest in URAT1 inhibitors remains strong. New players like Atom Therapeutic, or the recently launched Crystalys Therapeutics, continue to pursue the space, signaling unmet demand and fresh investor belief in better therapies.

What’s next: Arthrosi completed enrollment for the two phase 3 trials in 2025, setting the stage for data drops in 2026 and a possible approval filing.