Arthrosi Therapeutics raised $153 million in a Series E financing led by Prime Eight Capital to complete two fully enrolled Phase 3 trials of AR882 (pozdeutinurad), a next‑generation URAT1 inhibitor for gout. The San Diego company plans to use the funds to support regulatory and commercial readiness as Phase 3 readouts are expected in Q2 2026. Arthrosi positions AR882 as a highly selective URAT1 blocker that may avoid kidney toxicity associated with earlier URAT1 agents; the molecule completed mid‑stage testing and the company claims potential best‑in‑class properties. The financing reflects increased investor interest in better oral gout medicines amid limited options beyond allopurinol and biologic infusions. The round also highlights competitive dynamics: other players including Crystalys (dotinurad rights) and several Asian developers are advancing URAT1 programs, setting up a crowded late‑stage market if multiple agents demonstrate differentiated safety or efficacy.