-First precision approach to IBD by utilizing a companion diagnostic to identify patients-

-Phase 2a initiation in Crohn’s Disease on track for 3rd Quarter 2021-

– Further details to be provided at R&D Day on July 28th

SAN DIEGO, CA, USA I July 19, 2021 I 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, starting first with inflammatory bowel disease (IBD), today announced the initiation of the Phase 2 ARTEMIS-UC clinical trial evaluating PRA023 for moderate-to-severe ulcerative colitis (UC), with first patient enrollment. The study is placebo-controlled and statistically powered to evaluate the efficacy and safety of PRA023 in UC patients.   The company plans to provide more details of the Phase 2 ARTEMIS-UC study at R&D Day on July 28th.

“The majority of patients with UC cannot achieve clinical remission through the use of currently available therapies,” said Allison Luo, MD, Chief Medical Officer of Prometheus. “This gives Prometheus compelling motivation to rapidly advance PRA023, addressing both inflammation and fibrosis and leading the precision medicine approach in the IBD space, starting first with the ARTEMIS-UC study.”

Prometheus has recently completed the dosing phase of the Phase 1a clinical trial of PRA023, a single center, double-blind, placebo-controlled trial to determine the safety, tolerability, pharmacokinetics, and pharmacodynamics of PRA023 in normal healthy volunteers. Safety and tolerability observed to date supports the initiation of a Phase 2 trial. Final Phase 1a results of PRA023 in UC and CD are expected in the fourth quarter of 2021. Further details will be provided at the company’s R&D Day on July 28, 2021. Register here: Prometheus R&D Day

About PRA023

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 the two most common forms of IBD, Ulcerative Colitis (UC) and Crohn’s Disease (CD). The Company has initiated enrollment in a Phase 2 trial in UC patients. The Company is also developing a genetic-based companion diagnostic 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 biotechnology company pioneering a precision medicine approach for the discovery, development, and commercialization of novel therapeutic and companion diagnostic products for the treatment and diagnosis of immune-mediated diseases, starting first with IBD. The Company’s precision medicine platform, Prometheus360™, combines proprietary bioinformatics discovery methods with one of the world’s largest gastrointestinal bioinformatics databases to identify novel therapeutic targets and develop therapeutic candidates to engage those targets.  Prometheus is headquartered in San Diego, CA.

SOURCE: Prometheus Biosciences