Dr. Allen Davidoff reports

XORTX ANNOUNCES PIONEERING RESEARCH ON GENOME-WIDE PATHOGENIC PATHWAYS IN GOUT AND PROVIDES A CORPORATE UPDATE

XORTX Therapeutics Inc. has highlighted recent peer-reviewed, independent, published research reports that expand current knowledge that genetic factors are linked to the overexpression of xanthine oxidase and high chronic uric acid concentrations in the blood and gout. These groundbreaking findings further support the company's approach to treating gout, kidney and other diseases by inhibiting XO.

Historically, high uric acid concentration in the blood has been associated with increased incidence of gout, inflammation and health consequences, attributed to diet and lifestyle choices. Xanthine oxidase is an essential enzyme within the uric acid metabolic pathway and is required for the breakdown of purine nucleotides. The breakdown products of XO, uric acid and reactive oxygen species are released during the enzymatic reaction, and may play a detrimental role in the circulatory system and within tissue during disease. XORTX-sponsored discoveries in rodent models of gout and polycystic kidney disease implicate overexpression or overactivity of XO as a potentially important target in treating this disease. Gout is a chronic disease that is caused by an innate immune response to deposits of uric acid crystals when uric acid is high.

Recent work by T.J. Major and colleagues presented evidence that, in a large clinical study of 2.6 million individuals, as many as 410 genetic factors (including 149 new factors) are associated with molecular mechanisms of the inflammatory component of gout. This clinical study aligns closely with evidence for overexpression of XO in humans and with work by Wang et al. suggesting linkage of genetic factors to PKD. Recently, new emerging discoveries link genetic factors to specific populations and show that higher XO expression is associated with a variety of conditions including hyperuricemia, sepsis, organ failure and sepsis associated acute respiratory distress syndrome, kidney dysfunction, diabetes, polycystic kidney disease, and kidney failure. From a mechanistic standpoint, these studies advocate for a precision medicine approach in which genetic risk variants would guide treatment decisions.

Commenting on the research, Allen Davidoff, PhD, chief executive officer of XORTX, stated: "This pioneering into the health consequences of hyperuricemia and linkage to genetic factor in gout and autosomal dominant polycystic kidney disease sponsored by XORTX and these peer-reviewed, published research papers support our belief that pharmacologic targeting of XO holds enormous therapeutic potential, specifically where increased XO activity is associated with non-diabetic or diabetic kidney diseases. These discoveries highlight an opportunity to develop a personalized therapeutic approach for individuals whose unique genetic factors predispose them to disease and the need for xanthine oxidase inhibition to treat those individuals at risk. We believe that XORTX's expertise in developing XO inhibitors, protected by a patent portfolio that anticipated this opportunity, combined with our therapeutic platform, is ideally positioned to deliver targeted therapeutics to individuals. Our planned clinical trial using our commercial formulation of oxypurinol will bring us ever closer preparing a NDA (new drug application) for this important gout therapy."

Corporate updates -- board changes, financing and Vectus Biosystems Ltd.

XORTX announces the appointment of Krysta Davies Foss as a director and the resignation of Bill Farley, Abigail Jenkins and Patrick Treanor reducing the board to five members. Ms. Davies Foss is a seasoned biotechnology executive with more than 25 years of experience advising pharmaceutical and biotechnology companies on development strategy, commercialization and market preparedness across a broad range of therapeutic areas. She currently serves as chief executive officer of Triad Strategic Services, a leading pharma and biotech strategy consulting firm. In addition to her executive role, Ms. Davies Foss serves on multiple boards, including the Canadian Organization for Rare Disorders, and has provided strategic intelligence and advisory services to organizations ranging from incubators and early-stage start-ups to large multinational pharmaceutical companies. Her experience spans the full product development life cycle from early innovation through global commercialization.

Dr. Davidoff stated: "The addition of Ms. Foss adds a strong board member to the company. Her depth of strategic insight and industry leadership will be a valuable asset as the company advances its clinical programs and long-term growth strategy. The company wishes to thank Bill Farley, Abigail Jenkins and Pat Treanor for their efforts on behalf of XORTX over the past several years."

The company also wishes to clarify its disclosure included in its news release of Oct. 29, 2025, announcing the closing of the $1.1-million (U.S.) registered direct offering. In that news release, the number of prefinanced warrants of 1,117,530 was incorrect. On closing, the company issued 572,470 common shares and 1,177,530, a difference of 60,000 prefinanced warrants, for total aggregate common shares and prefinanced warrants of 1.75 million. Further, the company confirms that, in addition to the 87,500 agent warrants granted to D. Boral Capital LLC exercisable at 69 U.S. cents per common share commencing 181 days following issuance for a period of 18 months, D. Boral Capital was also paid a cash commission of $77,175 (U.S.), equal to 7 per cent of the gross proceeds of the offering.

Finally, the company wishes to provide an update on timing for closing its acquisition of the renal anti-fibrotic therapeutic program from Vectus, an Australian Securities Exchange-listed company that was announced on Oct. 17, 2025. Vectus is awaiting approval from the ASX on whether shareholder approval is required for the sale of the VB4-P5 intellectual property. Pursuant to the binding term sheet that was entered into between XORTX and Vectus, closing is to occur no later than 90 days postsigning, being Jan. 13, 2026. XORTX and Vectus remain committed to finalizing the acquisition. The company will provide additional updates on timing for closing when clarity on ASX approval is received by Vectus.

About XORTX Therapeutics Inc.

XORTX is a pharmaceutical company with three clinically advanced products in development: (1) its lead program XRx-026 program for the treatment of gout; (2) XRx-008 program for ADPKD; and (3) XRx-101 for acute kidney and other acute organ injury associated with respiratory virus infections. In addition, the company is developing XRx-225, a preclinical-stage program for Type 2 diabetic nephropathy. XORTX is working to advance products that target aberrant purine metabolism and xanthine oxidase to decrease or inhibit production of uric acid. At XORTX, it is dedicated to developing medications that improve the quality of life and health of individuals with gout and other important diseases.

We seek Safe Harbor.