Prometheus Biosciences Initiates Third Phase 2 Study of PRA023 for Systemic Sclerosis-Associated Interstitial Lung Disease (SSc-ILD)

– First therapeutic candidate for the treatment of SSc-ILD targeting both key fibrotic and inflammatory pathways –

– ATHENA-SSc-ILD Phase 2 topline results expected first-half 2024 –

– FDA has granted Fast Track Designation for PRA023 for the treatment of SSc-ILD –

SAN DIEGO, March 30, 2022 (GLOBE NEWSWIRE) — Prometheus Biosciences, Inc. (Nasdaq: RXDX), a 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 it has enrolled its first patient in the ATHENA-SSc-ILD trial, a placebo-controlled and statistically powered Phase 2 study of PRA023 in SSc-ILD. The Company announced in January 2021 that PRA023 received Fast Track Designation from the US Food and Drug Administration for the treatment of SSc-ILD.

“PRA023, our anti-TL1A antibody, has shown the potential to be a differentiated, best-in-class precision therapy for multiple immune-mediated diseases and we now have three Phase 2 trials underway, demonstrating PRA023’s pipeline-in-a-product opportunity,” said Mark McKenna, Chairman and CEO of Prometheus. “Prometheus’ initiation of ATHENA-SSc-ILD exemplifies our team’s strong execution, marking the first indication of PRA023 outside of IBD.”

Systemic Sclerosis (SSc) is a rare autoimmune disorder characterized by progressive fibrosis of the skin and internal organs thought to result from inflammation and chronic immune activation. Lung involvement (SSc-ILD) is the leading cause of morbidity and mortality for individuals with the disorder. SSc-ILD has been largely irreversible with current therapeutic strategies focused on slowing progression of the disorder.

“We believe PRA023’s dual anti-fibrotic and anti-inflammatory mechanism of action is well-suited to address the underlying disease pathophysiology of SSc-ILD, where no disease modifying therapies currently exist,” said Allison Luo, M.D., Chief Medical Officer of Prometheus. “The initiation of the ATHENA-SSc-ILD study is an important milestone for the Company and for patients who are suffering from this rare disorder.”  

About the ATHENA-SSc-ILD Study

ATHENA-SSc-ILD is a placebo-controlled Phase 2 trial of PRA023 in SSc-ILD, enrolling 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 change in forced vital capacity (FVC) at 50 weeks. Secondary endpoints will be 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. We also plan to evaluate a variety of patient reported outcomes for dyspnea, disability, effects of skin thickening, and bowel function. ATHENA-SSc-ILD will also assess the performance of our companion diagnostic candidate for PRA023.

Upcoming 2022 Milestones and Events

• Update on UC and CD Phase 2 enrollment planned in 2Q
• Investigational Device Exemption (IDE) submission of the companion diagnostic for PRA023 planned in 3Q
• IND submission for PR600 planned for 3Q
• Topline results from the ARTEMIS-UC Phase 2 study expected in 4Q
• Topline results from APOLLO-CD Phase 2a study expected in 4Q

About PRA023: Pipeline in a Product

PRA023 is an IgG1 humanized monoclonal antibody (mAb) that has been shown to block tumor necrosis factor (TNF)-like ligand 1A (TL1A). PRA023 binds both soluble and membrane-associated human TL1A with high affinity and specificity and has the potential to substantially improve outcomes for moderate-to-severe IBD patients predisposed to increased TL1A expression. Prometheus is developing PRA023 for the treatment of immune-mediated diseases including Ulcerative colitis (UC), Crohn’s disease (CD), and systemic sclerosis-associated interstitial lung disease (SSc-ILD).

The Company is currently conducting three Phase 2 studies of PRA023: a Phase 2 trial in UC patients, a Phase 2a trial in CD patients, and a Phase 2 clinical trial in SSc-ILD, each utilizing a genetic-based companion diagnostic designed to identify patients who are predisposed to increased expression of TL1A and therefore potentially more likely to respond to PRA023.

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, Prometheus360^TM, 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.

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 the company’s current beliefs and expectations. Such forward-looking statements include, but are not limited to statements regarding: the potential therapeutic benefits of PRA023 and its ability to address a number of immune-mediated diseases; the design of Prometheus’ Phase 2 clinical trial in SSc-ILD; Prometheus’ timing to provide an update regarding enrollment in its ongoing Phase 2 clinical trial in UC and its ongoing Phase 2a clinical trial in CD as well as the timing to announce topline data from these studies; timing to submit an IDE for the its companion diagnostic candidate for PRA023; and the timing to submit an IND for Prometheus’ PR600 therapeutic candidate. The inclusion of forward-looking statements should not be regarded as a representation by Prometheus that any of its 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, and the company may not be able to develop any therapeutics or companion diagnostic products of commercial value; potential delays in the commencement, enrollment and completion of clinical trials and preclinical studies; Prometheus’ dependence on third parties in connection with product manufacturing, research and preclinical and clinical testing; Prometheus’ ability to develop companion diagnostics for its therapeutic product candidates; the success of clinical trials and preclinical studies for the company’s therapeutic product candidates and its companion diagnostic candidates; unexpected adverse side effects or inadequate efficacy of our product candidates that may limit their development, regulatory approval and/or commercialization, or may result in recalls or product liability claims; the results of preclinical studies and early clinical trials are not necessarily predictive of future results; Prometheus may not realize any benefits from its current and any future collaborations; regulatory developments in the United States and foreign countries; Prometheus’ ability to obtain and maintain intellectual property protection for its product candidates and maintain its rights under intellectual property licenses; Prometheus’ ability to maintain undisrupted business operations due to the COVID-19 pandemic, war and other international political and economic risks, in foreign countries, including delaying or otherwise disrupting its clinical trials, manufacturing and supply chain; and other risks described in the Company’s prior press releases and filings with the Securities and Exchange Commission (SEC), including under the heading “Risk Factors” in Prometheus’ most recent annual report on Form 10-K 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 Prometheus undertakes 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