Press Release, XORTX Files U.S. FDA Pre-IND Meeting Request for XRx-101 (Oxypurinol) COVID-19 Program and Pre-IND Meeting Submission

● Potential of Acute Kidney Injury Emerging as a Serious Consequence of COVID-19 ●

CALGARY, AB - August 31, 2020 – XORTX Therapeutics Inc. (CSE : XRX) (OTCQB : XRTXF)
(FRANKFURT : ANU1) (the “Company” or “XORTX”) a late clinical stage pharmaceutical development
company focused on kidney disease, is pleased announce that the Company has filed its pre-IND
(Investigational New Drug) meeting request with the U.S. FDA. This filing initiates formal communications
with the U.S. FDA regarding development of the Company’s proprietary formulation of XRx-101
(Oxypurinol) for the treatment and prevention of acute kidney injury (AKI) associated with COVID-19
coronavirus infection. The request for a pre-IND meeting was accompanied by the complete pre-IND
briefing document.

The application includes discussion of the clinical development plan and requests for guidance regarding
the novel proprietary formulation of Oxypurinol specifically designed to treat individuals at risk of AKI
associated with COVID-19 coronavirus infection.
This application with the U.S. FDA, opens discussions regarding the critical path plan to bring XRx-101 to
patients with COVID-19. The pre-IND package presents current data showing that:
1. COVID-19 is frequently accompanied by pneumonia, acute kidney injury, proteinuria, and hematuria1,2
which can lead to multiple organ failure and death.
2. Though early reports suggested a low incidence (between 3% to 9%) of AKI in those with COVID-19
infection2,3,4, data from the U.S. indicates that 25-35% of patients hospitalized with COVID-19 develop
AKI.5-7
3. Up to 20% of those need renal replacement therapy (RRT), and the mortality rate in patients that
experience AKI in the setting of COVID-19 is several-fold higher than patients without AKI.6
4. AKI has been identified as an independent risk factor for patients’ in-hospital mortality due to COVID192.
5. In a study of hospitalized patients with AKI, a hypercatabolic phenotype in a significant proportion of
patients with AKI, manifested by extremely high serum uric acid levels8.
“This submission is an important step for the Company and the XRx-101 program and we move forward
with a strong belief, verified by human data, that XRx-101 (Oxypurinol) may be an effective treatment for
acute kidney injury that accompanies coronavirus (COVID-19),” stated Dr. Allen Davidoff, CEO of XORTX
Therapeutics, who added, “The focus and dedication of the XORTX team and our clinical development
partners made the rapid development of this pre-IND package and meeting request possible. We will
provide updates regarding discussions with the U.S. FDA.”
Currently, the US has accounted for nearly 6 million COVID-19 infections, with an estimated 330,000
hospitalizations, close to 180,000 deaths, 65,000 individuals that are now permanently on dialysis, and
nearly 44% (~80,000) of those released from hospital have ongoing acute kidney injury. In the absence of
a viable vaccine, during the next 12 months these numbers could grow two to three-fold, and could give
rise to a kidney disease crisis with substantial future socio-economic cost. A therapy to decrease the risk
of acute kidney injury due to COVID-19 infection would address the rapidly growing medical need.
The Company is not making any express or implied claims that it has the ability to eliminate, cure or contain
the COVID-19 coronavirus at this time.

About XRX-101 (Oxypurinol)
XORTX Therapeutics has developed XRx-101 (active ingredient Oxypurinol) a xanthine oxidase inhibitor
for the treatment of COVID-19 induced AKI. Two key studies (one in a mouse model of influenza and
another in herpes infection) have shown that XRx-101’s active ingredient, Oxypurinol, can act as (1) an
anti-viral, (2) uric acid lowering treatment, and (3) organ-protective therapy. Specifically, in the setting of
serious viral infection and tissue damage, XRx-101 can act to inhibit xanthine oxidase expression due to
hypoxia, or tissue destruction, thereby preventing increased serum uric acid (SUA) concentration from
reaching saturation levels at which uric acid crystals could trigger acute organ injury. Additionally, excipients
in the formulation such as L-arginine, a basic amino acid and nitric oxide source, can increase the aqueous
solubility of uric acid, thereby also decreasing uric acid crystal formation associated with tumor lysis-like
syndrome due to COVID-19 infection. L-arginine is also reported to protect against kidney injury, in the
setting of ischemia reperfusion injury. In concept, XRx-101 may ameliorate the severity of COVID-19
infection comorbidity, mortality, and damage to kidneys. This, in turn, could increase COVID-19 survival
rates, especially in vulnerable populations such as the elderly and those with underlying medical conditions,
while also lessening dependence on medical infrastructure and medical services.
References:
1. Naicker, S., Yang, C.-W., Hwang, S.-J., Liu, B.-C., Chen, J.-H. & Jha, V. The Novel Coronavirus 2019
epidemic and kidneys. Kidney Int. 97, 824–828 (2020).
2. Cheng, Y., Luo, R., Wang, K., Zhang, M., Wang, Z., Dong, L., Li, J., Yao, Y., Ge, S. & Xu, G. Kidney
impairment is associated with in-hospital death of COVID-19 patients. medRxiv 2020.02.18.20023242
3. Wang, D., Hu, B., Hu, C., Zhu, F., Liu, X., Zhang, J., Wang, B., Xiang, H., Cheng, Z., Xiong, Y., Zhao,
Y., Li, Y., Wang, X. & Peng, Z. Clinical Characteristics of 138 Hospitalized Patients with 2019 Novel
Coronavirus-Infected Pneumonia in Wuhan, China. JAMA - J. Am. Med. Assoc. 323, 1061–1069
(2020).
4. Guan, W., Ni, Z., Hu, Y., Liang, W., Ou, C., He, J., Liu, L., Shan, H., Lei, C., Hui, D. S., Du, B., Li, L.,
Zeng, G., Yuen, K.-Y., Chen, R., Tang, C., Wang, T., Chen, P., Xiang, J., et al. Clinical characteristics
of 2019 novel coronavirus infection in China. N. Engl. J. Med. 2
5. Hirsch JS, Ng JH, Ross DW, et al. Acute Kidney Injury in Patients Hospitalized with Covid-19. Kidney
Int. 2020.
6. Chan L, Chaudhary K, Saha A, et al. Acute Kidney Injury in Hospitalized Patients with COVID-19.
medRxiv. 2020:2020.2005.2004.20090944.
7. Mohamed MM, Lukitsch I, Torres-Ortiz AE, et al. Acute Kidney Injury Associated with Coronavirus
Disease 2019 in Urban New Orleans. Kidney360. 2020:10.34067/KID.0002652020.
8. http://www.xortx.com/2020/08/04/xortx-partners-with-mount-sinais-icahn-school-of-medicine-on-usbased-clinical-trial-in-covid-19/

About XORTX Therapeutics Inc.: XORTX Therapeutics Inc. is a biopharmaceutical company with three clinically advanced products in
development – XRx-008 for Autosomal Dominant Polycystic Kidney Disease (ADPKD), XRx-101 for
Coronavirus / COVID-19 infection and XRx-221 is a clinical stage program for Type 2 Diabetic Nephropathy
(T2DN). The Company has strong intellectual property rights and established proof of concept through
independent clinical studies. XORTX is working to advance its clinical development stage products that
target xanthine oxidase to inhibit production of uric acid. At XORTX Therapeutics, we are dedicated to
developing medications to improve the quality of life and future of patients.

Additional information on
XORTX Therapeutics is available at www.xortx.com.
For further information, please contact:
Allen Davidoff, CEO Bruce Rowlands, Chairman
adavidoff@xortx.com or +1 403 455 7727 browlands@xortx.com or +1 416 203 7260
The CSE has neither approved nor disapproved the contents of this news release.

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