News Release

Merus Announces Data from a Phase 1/2 Study of MCLA-128 to be Presented at the 2017 American Society of Clinical Oncology Annual Meeting

April 20, 2017 at 4:05 PM EDT

UTRECHT, The Netherlands, April 20, 2017 (GLOBE NEWSWIRE) -- Merus N.V. (NASDAQ:MRUS), a clinical-stage immuno-oncology company developing innovative bispecific antibody therapeutics, today announced that data from a Phase 1/2 study of MCLA-128 for the treatment of metastatic breast cancer will be presented in a poster session at the American Society of Clinical Oncology (ASCO) Annual Meeting, which will be held on June 2-6, 2017 in Chicago, Illinois.

Details of the poster presentation are as follows:

Title: First-in-human phase 1/2 study of MCLA-128, a full length IgG1 bispecific antibody targeting HER2 and HER3: Final phase 1 data and preliminary activity in HER2+ metastatic breast cancer (MBC)
Abstract Number: 2522
Poster Session: Developmental Therapeutics—Clinical Pharmacology and Experimental Therapeutics
Date and Time: Monday, June 5, 2017, 8:00 AM-11:30 AM CT

About MCLA-128
MCLA-128 is designed to block HER3/heregulin dependent tumor growth and survival as well as enhance immune-mediated killing of tumors. MCLA-128 employs a ‘dock and block’ mechanism in which the mode of HER2 receptor binding orientates the HER3 binding arm to effectively block oncogenic signaling through the HER2:HER3 heterodimer even under high heregulin concentrations. In addition, MCLA-128 is engineered for enhanced ADCC in order to recruit and activate immune effector cells to directly kill the tumor.

About Merus N.V.
Merus is a clinical-stage immuno-oncology company developing innovative full length human bispecific antibody therapeutics, referred to as Biclonics®. Biclonics® are based on the full-length IgG format, are manufactured using industry standard processes and have been observed in preclinical studies to have several of the same features of conventional monoclonal antibodies, such as long half-life and low immunogenicity. Merus' lead bispecific antibody candidate, MCLA-128, is being evaluated in a Phase 1/2 clinical trial in Europe as a potential treatment for HER2-expressing solid tumors. Merus' second bispecific antibody candidate, MCLA-117, is being developed in a Phase 1/ 2 clinical trial in patients with acute myeloid leukemia. The Company also has a pipeline of proprietary bispecific antibody candidates in preclinical development, including MCLA-158, which is designed to bind to cancer stem cells and is being developed as a potential treatment for colorectal cancer and other solid tumors, and Biclonics® designed to bind to various combinations of immunomodulatory molecules, including PD-1 and PD-L1.

Forward Looking Statement
Except for the historical information set forth herein, this press release contains predictions, estimates and other forward-looking statements, including without limitation statements regarding: the impact of the collaboration on Merus’ finances and clinical development, whether any of the programs under the collaboration will be successful; and whether and when Merus will receive any of the expected or potential payments under the collaboration and the amounts of such payments to Merus. These forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially from our expectations, including unanticipated developments in and risks related to: research and development efforts related to the collaboration programs; the clinical development process, which is expensive and unpredictable; the possibility that results of clinical trials may be unsuccessful or insufficient to meet applicable regulatory standards or warrant continued development; other market or economic factors; unanticipated delays; Merus’ ability to compete against parties with greater financial or other resources; Merus’ ability to commercialize and market its products, if approved; greater than expected expenses; and the other important factors detailed in Merus’ final prospectus filed with the Securities and Exchange Commission, or SEC, on May 20, 2016 relating to our Registration Statement on Form F-1, and its other reports filed with the SEC. Merus disclaims any intent or obligation to update these forward-looking statements. These forward-looking statements should not be relied upon as representing Merus’ views as of any date subsequent to the date of this press release.

Contacts:
Media:
Eliza Schleifstein
+1 973 361 1546
eliza@argotpartners.com

Investors:
Kimberly Minarovich
+1 646 368 8014
kimberly@argotpartners.com

Merus N.V.