Less than a year after emerging from stealth, Crystalys Therapeutics has bagged a $130-million series B led by Frazier Life Sciences to carry its gout candidate over the clinical finish line and prepare for its potential commercialisation. New investors Wellington Management, HBM Healthcare Investments, Soleus Capital, Cormorant Asset Management, Trails Edge Capital Partners, Pivotal bioVenture Partners and KCap Biotechnology Fund also participated in the financing, as did all existing backers including Novo Holdings, SR One, Catalys Pacific, Perceptive Xontogeny Venture Funds, Lightstone Ventures, AN Venture Partners, funds managed by abrdn, KB Investments, Pontifax, Longwood Fund, Alexandria Venture Investments, Wedbush Healthcare Partners and Prebys Ventures Fund.Filling the gout treatment gapCrystalys is studying dotinurad, a once-daily, oral URAT1 inhibitor, in the Phase III RUBY trial involving 500 adults with hyperuricemia associated with gout, and in the Phase III TOPAZ trial of about 250 adults with tophaceous gout. The two studies, expected to finish in late 2027 per ClinicalTrials.gov, are comparing dotinurad against the xanthine oxidase inhibitor allopurinol, a standard first-line treatment for gout that lowers the body's production of uric acid. According to the biotech, there are few treatment options for patients with chronic gout who don't respond to first-line treatments. Amgen's intravenous Krystexxa (pegloticase) can be given to patients with severe gout as a last-line option, but the therapy can cause nausea, vomiting and infusion reactions; it also carries a boxed warning for severe allergic reactions. By blocking URAT1, a key urate transporter involved in renal uric acid reabsorption and excretion, dotinurad is designed to increase uric acid excretion by the kidney. Crystalys believes it has the potential to serve as a second-line oral treatment option for patients who don't respond to allopurinol, "addressing a significant treatment gap between xanthine oxidase inhibitors and intravenous uricase."Wednesday's financing, which adds to its $205-million series A raised last year, is expected to support the RUBY and TOPAZ studies, along with the Phase II AMETHYST study testing dotinurad in patients who are intolerant to xanthine oxidase inhibitors or failed uricase treatment, and provide sufficient runway for Crystalys to hit several clinical and regulatory milestones. However, even if dotinurad is successfully greenlit by the FDA for gout, it may hit shelves behind a rival product from Swedish Orphan Biovitrum (Sobi). The drugmaker in December agreed to spend $950 million upfront to buy Arthrosi Therapeutics and its once-daily oral URAT1 inhibitor, pozdeutinurad. A pivotal readout from the Phase III REDUCE 1 trial evaluating pozdeutinurad in patients with gout is expected this half, while the REDUCE 2 trial in May met its primary efficacy endpoint in adults inadequately controlled or uncontrolled gout.