News Release

Prometheus Biosciences Provides Enrollment Update in APOLLO-CD and ARTEMIS-UC Global Phase 2 Studies

June 8, 2022

- Enrollment completed ahead of schedule for APOLLO-CD Phase 2a study of PRA023 in Crohn’s disease patients -

- ARTEMIS-UC Phase 2 Cohort 1 enrollment on track with completion expected 3Q 2022 -

- Both APOLLO-CD and ARTEMIS-UC topline results expected 4Q 2022 –

SAN DIEGO, June 08, 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 an enrollment update on the APOLLO-CD and ARTEMIS-UC trials. The company has completed enrollment for APOLLO-CD, a global Phase 2a study of PRA023 in Crohn’s Disease (CD) and enrollment remains on track in the Phase 2 study of PRA023 for ARTEMIS-UC in ulcerative colitis (UC) with enrollment completion of cohort 1 expected in the third quarter of this year. Topline results from both APOLLO-CD and ARTEMIS-UC are expected in the fourth quarter of this year.

“Completing enrollment of APOLLO-CD is a major milestone for the trial and an important achievement for Prometheus given the expeditious speed in the execution of our trials,” said Mark McKenna, Chairman and Chief Executive Officer of Prometheus. “We believe that the strong interest we have seen from investigators and the accelerated pace of trial enrollment demonstrates there is a clear and compelling need to address both inflammation and fibrosis in IBD and we look forward to reading out our topline results later this year.”

“APOLLO-CD enrollment completion is an important landmark for both Prometheus and for people living with Crohn’s disease. We are also nearing completion of enrollment for the initial cohort in our ARTEMIS-UC study and expect our Enroll360TM platform to expedite enrollment in the expansion cohort in this study which will evaluate the effectiveness of our companion diagnostic,” said Allison Luo, M.D., Chief Medical Officer of Prometheus. “We continue to advance a very broad, global development program for PRA023, evaluating its efficacy and safety in three immune-mediated diseases across three Phase 2 studies, while continuing to meet aggressive timelines to swiftly bring this promising therapy to patients.”  

With Enroll360TM, Prometheus has been building a global network of trial-ready sites where over 2,500 patients have already been genetically profiled and clinically characterized to determine their eligibility for Prometheus’ current and future clinical trials. Prometheus plans to utilize this patient recruitment platform to accelerate patient identification and increase the rate of enrollment for the company’s biomarker-guided clinical trials, starting with the expansion cohort of the ARTEMIS-UC Phase 2 study. 

The company also remains on track for implementing its subcutaneous formulation for registrational studies in UC and CD, with an industry-leading subcutaneous formulation of 200 mg/ml. This will potentially eliminate the conventional need to bridge with a pre-filled syringe. In the first quarter of this year, Prometheus initiated a subcutaneous bridging study by dosing Caucasian normal healthy volunteers with PRA023 to assess the bioavailability of the subcutaneous formulation. In addition, Prometheus also initiated dosing of healthy volunteers of Japanese descent with PRA023 as part of the bridging study to assess safety, tolerability, and pharmacokinetics.  

Webcast Information

Prometheus management will be presenting at the Jefferies Healthcare Conference today at 10:00am ET. A live and archived webcast of the presentation will be available via the Events & Webcasts page on the Investor section of the Prometheus Biosciences website.

About PRA023: Pipeline in a Product

PRA023 is an IgG1 humanized monoclonal antibody 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 UC, 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, ARTEMIS-UC, a Phase 2a trial in CD patients, APOLLO-CD, and a Phase 2 clinical trial in SSc-ILD, ATHENA-SSc, each utilizing a genetic-based companion diagnostic candidate designed to identify patients who are predisposed to increased expression of TL1A and therefore potentially more likely to respond to PRA023.

Prometheus’ Phase 2 ARTEMIS-UC clinical trial is currently enrolling patients with moderate-to-severely active UC who have failed conventional therapy, including biologics. The trial is a 12-week, double-blind, placebo-controlled, randomized study to evaluate the efficacy and safety of PRA023 in patients with UC. The initial cohort is statistically powered to evaluate the efficacy of PRA023 in 120 patients with UC and topline results are expected in 4Q 2022. The expansion cohort is statistically powered to further evaluate the effectiveness of the company’s companion diagnostic in approximately 40 additional patients with UC who have also been classified as positive by the companion diagnostic.

Prometheus’ Phase 2a APOLLO-CD clinical trial is a 12-week open label study that has completed enrollment in 50 patients with moderate-to-severely active CD with endoscopically active disease who have failed conventional therapy, including biologics. The study will assess the efficacy of PRA023 and the effectiveness of the company’s companion diagnostic in patients with CD. Topline results for the Phase 2a APOLLO-CD trial are expected in 4Q 2022.

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.

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 timing of enrollment and topline results of Prometheus’ APOLLO-CD and ARTEMIS-UC trials; Prometheus’ Enroll360TM program and the company’s ability to accelerate enrollment in its planned and other future clinical trials; and the ability of Prometheus’ genetic-based companion diagnostic candidate to classify patients who are predisposed to increased expression of TL1A or more likely to respond to PRA023. 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 TM is unproven; potential delays in the commencement, enrollment and completion of clinical trials and preclinical studies; the Enroll360 TM program may not increase the efficiency or enrollment rates in clinical trials; Prometheus’ dependence on third parties in connection with product manufacturing, research and preclinical and clinical testing; Prometheus’ ability to develop companion diagnostics for our therapeutic product 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 our current and any future collaborations; regulatory developments in the United States and foreign countries; Prometheus’ ability to obtain and maintain intellectual property protection for our product candidates and maintain our rights under intellectual property licenses; Prometheus’ ability to maintain undisrupted business operations due to the COVID-19 pandemic, 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 our Form 10-K filed with the SEC on March 9, 2022 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 except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. 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.

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

Media contact:
Juniper Point
Amy Conrad
(858) 914-1962
media@prometheusbiosciences.com