Crystalys Therapeutics Advances Global Phase 3 Program as RUBY Gout Trial Begins Dosing in Europe

New updates have been reported about Crystalys Therapeutics.

Crystalys Therapeutics has expanded its global Phase 3 program for dotinurad, initiating first patient dosing at European clinical sites in its pivotal RUBY trial for gout-related hyperuricemia. The San Diego–based clinical-stage biopharmaceutical company is developing dotinurad, a once-daily oral URAT1 inhibitor, as a potential second-line therapy for patients who do not achieve adequate control on allopurinol, the standard first-line xanthine oxidase inhibitor. CEO James Mackay described the start of European dosing as a key operational milestone in the RUBY study, signaling continued momentum in the company’s late-stage development timeline and strengthening the asset’s positioning for eventual U.S. and EU regulatory filings.

RUBY is a randomized, double-blind, multicenter Phase 3 trial that will enroll approximately 500 patients with gout-associated hyperuricemia, who will receive once-daily dotinurad for up to 64 weeks to assess safety and efficacy. Strategically, this trial targets a well-defined treatment gap between first-line XOIs and last-line uricase therapies in the U.S. and Europe, where there are currently no suitable second-line oral options for patients who fail initial therapy. Dotinurad has already been approved in several Asian markets, including Japan, China, the Philippines, and Thailand, providing an existing body of clinical and real-world data to support its potential best-in-class safety and efficacy profile. For Crystalys, successful completion of the RUBY study and its broader global Phase 3 program would underpin regulatory submissions, enable a future commercial launch in major markets, and position the company as a focused gout franchise addressing a large, persistent unmet need in inflammatory arthritis.