News Release

Merus Presents Preclinical Data on MCLA-129 at the American Association for Cancer Research Annual Meeting 2022

April 8, 2022 at 1:00 PM EDT

– MCLA-129 promotes Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) and Antibody-Dependent Cell-Mediated Phagocytosis (ADCP) of non-small cell lung cancer (NSCLC) cells
– MCLA-129 significantly inhibits growth of a patient-derived EGFR exon20 insertion (exon20ins) tumor in a preclinical xenograft model

UTRECHT, The Netherlands and CAMBRIDGE, Mass., April 08, 2022 (GLOBE NEWSWIRE) -- Merus N.V. (Nasdaq: MRUS) (“Merus”, “the Company”, “we”, or “our”), a clinical-stage oncology company developing innovative, full-length multispecific antibodies (Biclonics® and Triclonics®), today released pre-clinical data highlighting the mechanism of action of MCLA-129. The poster, that is currently available virtually, will be presented at the American Association for Cancer Research (AACR) Annual Meeting 2022 in New Orleans, Louisiana on Sunday, April 10, 2022.

“Our preclinical study of MCLA-129 in non-small cell lung cancer cell lines is encouraging and continues to support the phase 1/2 trial, currently in dose escalation,” said Dr. Cecile Geuijen, Senior Vice President and Chief Science Officer at Merus. “We look forward to providing a clinical update from that study in the second half of 2022.”

Observations in the preclinical presentation include:

  • MCLA-129 inhibits ligand-induced EGFR and c-MET receptor dimerization and phosphorylation
  • MCLA-129 promotes ADCC and ADCP of NSCLC cells
  • MCLA-129 significantly inhibits growth of a patient-derived EGFR exon20ins tumor in a preclinical xenograft model
  • These data provide support for the ongoing phase 1/2 study of MCLA-129 in patients with solid tumors, including NSCLC with EGFR exon20ins (Study MCLA-129-CL01, NCT04868877)

The full poster is available on our website.

MCLA-129 is currently enrolling patients in a phase 1/2, open-label clinical trial consisting of dose escalation followed by a planned dose expansion. Primary objectives of phase 1 are to determine the maximum tolerated dose and/or the recommended phase 2 dose, and the objectives of phase 2 are to evaluate safety, tolerability and potential clinical activity in patients with advanced solid tumors. MCLA-129 is subject to a collaboration and license agreement with Betta Pharmaceuticals Co. Ltd. (Betta), which permits Betta to develop MCLA-129 exclusively in China, while Merus retains global rights outside of China. Merus plans to provide a clinical update in the second half of 2022.

About MCLA-129
MCLA-129 is an antibody-dependent cellular cytotoxicity-enhanced Biclonics® that is designed to inhibit the EGFR and c-MET signaling pathways in solid tumors. Preclinical data have shown that MCLA-129 can effectively treat TKI-resistant non-small cell lung cancer in xenograft models of cancer. MCLA-129 is designed to have two complementary mechanisms of action: blocking growth and survival pathways to stop tumor expansion and recruitment and enhancement of immune effector cells to eliminate the tumor.

About Merus N.V.
Merus is a clinical-stage oncology company developing innovative full-length human bispecific and trispecific antibody therapeutics, referred to as Multiclonics®. Multiclonics® are manufactured using industry standard processes and have been observed in preclinical and clinical studies to have several of the same features of conventional human monoclonal antibodies, such as long half-life and low immunogenicity. For additional information, please visit Merus’ website, and

Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation, statements regarding the content and timing of clinical trials, data readouts and clinical updates for MCLA-129; the advancement of the phase 1/2 trial for MCLA-129 and the planned update in second half of 2022; the design and treatment potential of MCLA-129 and impact of its preclinical data; our collaboration and license agreement with Betta, which permits Betta to exclusively develop MCLA-129 in China, while Merus retains full ex-China rights, and any developments that may arise from these agreements. These forward-looking statements are based on management’s current expectations. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: our need for additional funding, which may not be available and which may require us to restrict our operations or require us to relinquish rights to our technologies or antibody candidates; potential delays in regulatory approval, which would impact our ability to commercialize our product candidates and affect our ability to generate revenue; the lengthy and expensive process of clinical drug development, which has an uncertain outcome; the unpredictable nature of our early stage development efforts for marketable drugs; potential delays in enrollment of patients, which could affect the receipt of necessary regulatory approvals; our reliance on third parties to conduct our clinical trials and the potential for those third parties to not perform satisfactorily; impacts of the COVID-19 pandemic; we may not identify suitable Biclonics® or bispecific antibody candidates under our collaborations or our collaborators may fail to perform adequately under our collaborations; our reliance on third parties to manufacture our product candidates, which may delay, prevent or impair our development and commercialization efforts; protection of our proprietary technology; our patents may be found invalid, unenforceable, circumvented by competitors and our patent applications may be found not to comply with the rules and regulations of patentability; we may fail to prevail in potential lawsuits for infringement of third-party intellectual property; our registered or unregistered trademarks or trade names may be challenged, infringed, circumvented or declared generic or determined to be infringing on other marks; and risks related to our ceasing to qualify as an emerging growth company and a smaller reporting company after December 31, 2021.

These and other important factors discussed under the caption “Risk Factors” in our Annual Report on Form 10-K for the period ended December 31, 2021, filed with the Securities and Exchange Commission, or SEC, on February 28, 2022, and our other reports filed with the SEC, could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management’s estimates as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change, except as required under applicable law. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this press release.

Multiclonics®, Biclonics® and Triclonics® are registered trademarks of Merus N.V.

Investor and Media Inquiries:
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Merus N.V.
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Merus N.V.
IR/Corp Comms

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