Prometheus Biosciences Provides Corporate Updates at the 40th Annual J.P. Morgan Healthcare Conference

– Fast Track Designation granted from U.S. Food and Drug Administration for PRA023 for the treatment of Systemic Sclerosis-Associated Interstitial Lung Disease (SSc-ILD) –

– New patent granted for PRA023 companion diagnostic (CDx) reinforces Prometheus’ precision approach and extends CDx patent coverage into 2040 –

– Company to present today at 1:30 PM EST –

SAN DIEGO, Jan. 12, 2022 (GLOBE NEWSWIRE) —  Prometheus Biosciences, Inc. (Nasdaq: RXDX), a clinical-stage biotechnology company pioneering a precision medicine approach for the discovery, development, and commercialization of novel therapeutic and companion diagnostic products for the treatment of immune-mediated diseases, today announced that management will discuss the following updates at the 40th Annual J.P. Morgan Healthcare Conference.

Fast Track Designation
The US FDA has granted Fast Track Designation for Prometheus’ lead therapeutic candidate, PRA023, for the treatment of Systemic Sclerosis-Associated Interstitial Lung Disease (SSc-ILD).

“We are pleased to have received Fast Track Designation for PRA023 in SSc-ILD as it clearly demonstrates that the FDA recognizes the importance of expeditiously evaluating potential treatments for SSc-ILD and the need for improved clinical outcomes for patients with this debilitating disease,” said Chairman and CEO, Mark McKenna. “Based on our positive topline Phase 1 results, and receipt of Fast Track Designation, we believe PRA023 is well-positioned to deliver on our mission to have a broad impact on patients with SSc-ILD. If successful in Phase 2 clinical trials, Prometheus would seek Breakthrough Therapy Designation in SSc-ILD given that there are currently no approved disease modifying therapies.”

Fast Track Designation aims to facilitate the development and accelerate the review of new therapeutics that are intended to treat serious or life-threatening conditions and potentially address an unmet medical need. Drugs that are granted this designation are given the opportunity for more frequent interactions with the FDA, as well as potential pathways for expedited approval.

The Company plans to initiate patient enrollment in ATHENA-SSc-ILD in the first quarter of 2022.   ATHENA-SSc-ILD is a placebo-controlled Phase 2 trial of PRA023 in SSc-ILD, with anticipated enrollment of approximately 100 patients who will be randomized 1:1 to either the active or placebo arm. The primary endpoint of the trial will be the annual rate of change in forced vital capacity (FVC) at 50 weeks. Secondary endpoints will be the change in quantitative interstitial lung disease by centrally-read high-resolution computed tomography (HRCT) and improvement in the American College of Rheumatology Combined Response Index in Diffuse SSc (ACR-CRISS) score.

New Patent Granted
The U.S. Patent and Trademark Office (USPTO) has granted a U.S. patent to Prometheus covering its companion diagnostic technology. US Patent No. 11,136,386 B2​ covers claims directed to methods of treating Crohn’s disease or ulcerative colitis by administering inhibitors of tumor necrosis factor-like cytokine 1A (TL1A) to patients selected by a defined companion diagnostic test. This newly granted patent reinforces Prometheus’ precision approach and extends the Company’s patent coverage of its PRA023 companion diagnostic into 2040.

Prometheus’ companion diagnostic is being utilized across its Phase 2 studies to identify patients that we believe may be more likely to respond to PRA023. The companion diagnostic was developed through the Company’s Prometheus360TM platform, which combines one of the world’s largest GI bioinformatics databases with a custom-built suite of data science tools, designed to guide drug discovery and enable the matching of drug mechanism to patient biology, and has been validated in more than 400 IBD patients.

Presentation at the 40th Annual J.P. Morgan Healthcare Conference
Prometheus will webcast its corporate presentation from the 40th Annual J.P. Morgan Healthcare Conference today, January 12, 2022 at 1:30 PM ET. The presentation will be webcast live on the Events & Webcasts page on the Investor section of Prometheus’ website and will be available for 30 days following the presentation. It is recommended that users connect to Prometheus’ website several minutes prior to the start of the webcast to ensure a timely connection.

About Prometheus Biosciences
Prometheus Biosciences, Inc. is a clinical-stage biotechnology company pioneering a precision medicine approach for the discovery, development, and commercialization of novel therapeutic and companion diagnostic products for the treatment of immune-mediated diseases. The Company’s precision medicine platform, Prometheus360TM, combines proprietary machine learning-based analytical approaches with one of the world’s largest gastrointestinal bioinformatics databases to identify novel therapeutic targets and develop therapeutic candidates to engage those targets.

The Company’s lead candidate, PRA023, is an IgG1 humanized monoclonal antibody (mAb) in development for the treatment of immune-mediated diseases, including ulcerative colitis (UC), Crohn’s disease (CD), and a recently announced third indication, systemic sclerosis-associated interstitial lung disease (SSc-ILD). The Company is currently conducting a Phase 2 trial in UC patients and a Phase 2a trial in CD patients, each utilizing a genetics-based companion diagnostic designed to identify patients who are predisposed to increased expression of TL1A and therefore potentially more likely to respond to PRA023. The company also plans to initiate a Phase 2 clinical trial for PRA023 in SSc-ILD in the first quarter of 2022.

Forward Looking Statements
Prometheus cautions readers that statements contained in this press release regarding matters that are not historical facts are forward-looking statements. These statements are based on our current beliefs and expectations. Such forward-looking statements include, but are not limited to statements regarding the potential benefits of Fast Track Designation, the timing of the initiation and enrollment of Prometheus’ planned Phase 2 clinical trial for PRA023 in SSc-ILD, the potential benefits of PRA023 for patients with SSc-ILD, Prometheus’ plans to use its PRA023 companion diagnostic in future clinical trials, the potential benefits of Prometheus360, and the anticipated term of IP protection for PRA023 and its companion diagnostic. The inclusion of forward-looking statements should not be regarded as a representation by Prometheus that any of our plans will be achieved. Actual results may differ from those set forth in this press release due to the risks and uncertainties inherent in our business, including, without limitation: Prometheus’ approach to the discovery and development of precision medicines based on Prometheus360 is unproven; potential delays in the commencement, enrollment and completion of preclinical studies and future clinical trials, including due to the COVID-19 pandemic; Prometheus’ dependence on third parties in connection with product manufacturing, research and preclinical and clinical testing, and potential supply chain disruptions related to the COVID-19 pandemic; Prometheus’ ability to develop, validate and commercialize a companion diagnostic for PRA023 in multiple indications; Prometheus may not realize the potential benefits of Fast Track Designation; and other risks described in our prior press releases and filings with the Securities and Exchange Commission (SEC), including under the heading “Risk Factors” in our most recent quarterly report on Form 10-Q and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and we undertake no obligation to update such statements to reflect events that occur or circumstances that exist after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

Prometheus Biosciences Contact:
Noel Kurdi
VP Investor Relations and Communications
(646) 241-4400
nkurdi@prometheusbiosciences.com

Media contact:
Juniper Point
Amy Conrad
(858) 914-1962
amy@juniper-point.com