Merck Strengthens Immunology Pipeline with Acquisition of Prometheus Biosciences, Inc.

April 16, 2023 6:00 am ET

RAHWAY, N.J. & SAN DIEGO–(BUSINESS WIRE)– Merck (NYSE: MRK), known as MSD outside the United States and Canada, and Prometheus Biosciences, Inc. (“Prometheus”) (Nasdaq: RXDX) today announced that the companies have entered into a definitive agreement under which Merck, through a subsidiary, has agreed to acquire Prometheus for $200.00 per share in cash for a total equity value of approximately $10.8 billion.

“At Merck, we are committed to delivering on our purpose to save and improve lives and continue to identify and secure opportunities where compelling science and value creation align,” said Robert M. Davis, chairman and chief executive officer, Merck. “The agreement with Prometheus will accelerate our growing presence in immunology where there remains substantial unmet patient need. This transaction adds diversity to our overall portfolio and is an important building block as we strengthen the sustainable innovation engine that will drive our growth well into the next decade.”

Prometheus 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 lead candidate, PRA023, is a humanized monoclonal antibody (mAb) directed to tumor necrosis factor (TNF)-like ligand 1A (TL1A), a target associated with both intestinal inflammation and fibrosis.

“Prometheus was established to revolutionize the treatment of immune-mediated diseases through the application of a powerful precision medicine approach,” said Mark McKenna, chairman and chief executive officer of Prometheus Biosciences. “This agreement with Merck, a leader in biopharmaceutical research and development, allows Prometheus to maximize the potential for PRA023, while continuing to apply our technology and expertise to fuel further discoveries to address the needs of patients with immune disorders.”

Prometheus is developing PRA023 for the treatment of immune-mediated diseases including ulcerative colitis (UC), Crohn’s disease (CD), and other autoimmune conditions. In December 2022, the company announced positive results for PRA023 from ARTEMIS-UC, a Phase 2, placebo controlled, study evaluating safety and efficacy in patients with moderate to severely active UC and APOLLO-CD a Phase 2A, open-label, study evaluating safety and efficacy in patients with moderate to severe CD. The findings were recently presented at the 18^th Congress of European Crohn’s and Colitis Organisation (ECCO).

“By applying a portfolio of powerful analytic tools to a comprehensive collection of IBD samples, Prometheus identified important disease insights that have now yielded a promising late-stage candidate,” said Dr. Dean Y. Li, president, Merck Research Laboratories. “I look forward to working with the talented Prometheus team to establish a new paradigm of precision treatment for immune diseases.”

Under the terms of the acquisition agreement, Merck, through a subsidiary, will acquire all of the outstanding shares of Prometheus. The acquisition is subject to Prometheus Biosciences shareholder approval. The closing of the proposed transaction will be subject to certain conditions, including the expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act and other customary conditions. The transaction is expected to close in the third quarter of 2023.

A copy of the merger agreement pursuant to the transaction will be filed with the Securities and Exchange Commission (“SEC”) and will be publicly available. In addition, Merck and Prometheus will file annual, quarterly and current reports and other information with the SEC, which are available to the public from commercial document-retrieval services and at the SEC’s website at www.sec.gov. Copies of the documents filed with the SEC by Merck may be obtained at no charge on Merck’s internet website at www.merck.com or by contacting Merck at 126 East Lincoln Avenue P.O. Box 2000, Rahway, NJ 07065 USA, or (908) 740-4000. Copies of the documents filed with the SEC by Prometheus may be obtained at no charge on Prometheus’ internet website at https://www.prometheusbiosciences.com or by contacting Prometheus at 3050 Science Park Road, San Diego, CA 92121 or (646) 241-4400.

Advisors

Morgan Stanley & Co. LLC acted as financial advisor to Merck in this transaction and Paul, Weiss, Rifkind, Wharton & Garrison LLP as its legal advisors. Centerview Partners LLC and Goldman Sachs & Co. LLC acted as financial advisors to Prometheus and Latham & Watkins LLP as the company’s legal advisor.