Crystalys Therapeutics doses first patients in Fortress Biotech’s global Phase 3 gout trial of Dotinurad, targeting safer uric acid control

Fortress Biotech, Inc. (NASDAQ: FBIO) and its majority-owned subsidiary Urica Therapeutics, Inc. have announced that the first patients have been dosed in Crystalys Therapeutics’ global Phase 3 clinical program evaluating Dotinurad for the treatment of gout. The pivotal studies—known as RUBY and TOPAZ—will directly compare Dotinurad to the standard of care, Allopurinol, in adults with hyperuricemia associated with gout and tophaceous gout, respectively. Both studies have been registered on ClinicalTrials.gov (NCT07089875 and NCT07089888).

Crystalys, the clinical-stage pharmaceutical company advancing Dotinurad under a licensing and equity agreement with Urica, will oversee these late-stage trials spanning North America, Europe, and Asia. The dosing milestone not only marks the first global pivotal evaluation of the urate transporter 1 (URAT1) inhibitor outside Japan but also underscores Fortress Biotech’s continued diversification into specialty therapeutics that balance innovation, risk management, and strategic capital allocation.

How the Dotinurad Phase 3 program is designed to establish superiority over Allopurinol in gout management worldwide

According to Crystalys Therapeutics, the RUBY trial will enroll approximately 500 adult patients with hyperuricemia associated with gout across multiple international sites and is expected to run for up to 64 weeks. The TOPAZ trial will include around 250 patients diagnosed with tophaceous gout and will extend to 76 weeks. Both trials will utilize a parallel-arm design comparing once-daily oral Dotinurad to a stable dose of physician-determined Allopurinol. The primary endpoints include serum uric acid reduction and the proportion of participants achieving target levels below 6 mg/dL without severe adverse events such as renal toxicity or hepatic enzyme elevations.

Dotinurad functions by selectively inhibiting URAT1, a renal transport protein that reabsorbs uric acid from the proximal tubule back into the bloodstream. By blocking this pathway, Dotinurad enhances uric acid excretion and lowers plasma levels in a mechanism complementary to xanthine oxidase inhibitors such as Allopurinol and Febuxostat. This approach is designed to offer superior control for patients whose uric acid levels remain elevated despite standard therapy — a population that represents a significant clinical unmet need worldwide.

Urica Therapeutics acquired North American and European rights to Dotinurad from Japan’s Fuji Yakuhin in 2023 and subsequently partnered with Crystalys Therapeutics to advance its global development. In exchange for transferring development responsibilities and related intellectual property, Urica retains 35 percent equity ownership in Crystalys and a three percent royalty on future net sales of Dotinurad. This model allows Fortress and Urica to maintain financial exposure to the program’s success while mitigating the capital risk of late-stage trials.

The dual-study design is strategically structured to address two distinct patient segments within the gout continuum — those with non-tophaceous disease where hyperuricemia drives recurrent flares, and those with tophaceous manifestations requiring long-term disease modification. Results from these studies are expected to support regulatory submissions in the U.S., Canada, and the European Union by 2026 or 2027.

Why the global gout drug market positions Dotinurad as a differentiated entrant in a crowded therapeutic space

The gout market has remained relatively static for decades, dominated by Allopurinol and Febuxostat, both xanthine oxidase inhibitors that limit uric acid production rather than enhancing its excretion. Despite their widespread use, up to 40 percent of patients fail to achieve optimal serum uric acid levels, and some experience drug intolerance or contraindications related to renal impairment or hypersensitivity. This gap has created demand for next-generation uricosuric agents with better safety profiles and predictable pharmacokinetics.

Dotinurad, marketed as Urece® in Japan since 2020, has already demonstrated significant uric acid lowering efficacy in Asian populations with a favorable tolerability profile. Its Western development aims to replicate these outcomes across genetically diverse cohorts and validate its global utility. Crystalys Therapeutics is expanding the clinical geography to include sites in the U.S., U.K., Germany, and South Korea, reflecting a broad regulatory ambition.

For Fortress Biotech, which operates a portfolio of more than 30 subsidiaries and partner companies across therapeutic verticals from oncology to rare diseases, Dotinurad represents its first late-stage metabolic program with potential for royalty generation in the mid-term pipeline. This advancement also aligns with Fortress’s asset-light development philosophy, in which subsidiaries advance or out-license clinical programs while the parent company retains economic rights and optionality. In essence, it is a risk-distributed model for biotech innovation.

How investor sentiment and equity positioning reflect market confidence in Fortress Biotech’s late-stage strategy

Following the announcement, shares of Fortress Biotech rose by approximately three percent, signaling renewed optimism in its clinical pipeline and asset monetization strategy. Analyst commentary highlighted that Phase 3 initiation serves as a validation milestone for the program and increases its perceived asset value on Fortress’s balance sheet. While the company has historically relied on partnered development and royalty streams from its subsidiaries such as Journey Medical and Checkpoint Therapeutics, the transition of Dotinurad into pivotal trials adds diversification to its revenue outlook.

Market sentiment among institutional investors appears moderately positive, supported by the limited capital exposure Fortress faces through its minority stake in Crystalys and its royalty entitlement. At the same time, analysts note that the global gout treatment market could exceed $3 billion by 2030, creating a sizable commercial incentive for novel therapies that can demonstrate superior safety and efficacy. Dotinurad’s selective mechanism and low drug-drug interaction profile make it a strong candidate for combination therapy or monotherapy in patients intolerant to current standard of care options.

For Urica Therapeutics, which was spun out of Fortress to develop metabolic disease assets, the milestone validates its mission to modernize gout treatment pathways through precision pharmacology. Chief executives from both Fortress and Crystalys have emphasized the goal of achieving a global registration package suitable for FDA and EMA submission without duplicative clinical programs — a strategy that could save years and tens of millions in development spending.

What the next 18 months of clinical milestones could reveal about the competitiveness of Dotinurad and the durability of Fortress Biotech’s growth model

The next phase for the Dotinurad program will likely involve progressive enrollment updates, periodic safety reviews, and potential interim analyses on uric acid response rates. If the results mirror the efficacy seen in Japanese registrational studies — where Dotinurad showed rapid and sustained uric acid reduction with minimal adverse events — it could emerge as the first globally approved URAT1 inhibitor with broad commercial potential. Industry analysts expect data readouts to occur in late 2026, followed by regulatory filings shortly thereafter.

For Fortress Biotech, the clinical progress of Dotinurad will serve as a litmus test for its subsidiary structure’s efficacy in generating long-term value without heavy cash burn. The company has recently adopted a disciplined financing strategy focused on non-dilutive capital infusions, asset divestitures, and strategic partnerships to extend its runway. Success in this trial series could solidify its reputation as a biotech incubator capable of scaling assets to commercialization through external partners while retaining economic upside.

As global gout prevalence continues to rise alongside metabolic syndrome and obesity trends, the market will continue to reward companies developing safer and more predictable treatments for chronic uric acid control. Fortress’s balanced risk exposure through Urica and Crystalys offers investors a unique hybrid between biotech innovation and financial prudence. If Dotinurad meets its Phase 3 goals, it could not only reshape the standard of care for gout but also validate Fortress Biotech’s portfolio model as a repeatable template for late-stage drug development.