• Petosemtamab in combination with pembrolizumab in 1L HNSCC initial interim clinical data selected for rapid oral session presentation
  
• MCLA-145 as monotherapy or in combination with pembrolizumab in solid tumors initial interim clinical data selected for rapid oral session presentation
• MCLA-129 in NSCLC with c-MET exon 14 skipping mutations initial interim clinical data selected for poster presentation

UTRECHT, The Netherlands and CAMBRIDGE, Mass., April 24, 2024 (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 announced the acceptance of three abstracts for presentation at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting, being held in Chicago, Illinois on May 31- June 4, 2024.

Rapid oral presentation:

Title: Petosemtamab (MCLA-158) with pembrolizumab as first-line (1L) treatment of recurrent/metastatic (r/m) head and neck squamous cell carcinoma (HNSCC): Phase 2 study
Abstract #: 6014
Session Title: Head and Neck Cancer
Session Date and Time: June 3, 2024, 8:00-9:30 a.m. CT

The presentation concerns petosemtamab evaluated in combination with pembrolizumab in patients with untreated advanced PD-L1+ HNSCC.

Rapid oral presentation:

Title: Phase I study of MCLA-145, a bispecific antibody targeting CD137 and PD-L1, in solid tumors, as monotherapy or in combination with pembrolizumab
Abstract #: 2520
Session Title: Developmental Therapeutics—Immunotherapy
Session Date and Time: June 2, 2024, 11:30 a.m.-1:00 p.m. CT

The presentation concerns MCLA-145 evaluated as monotherapy or in combination with pembrolizumab in patients with solid tumors.

Poster presentation:

Title: Efficacy and safety of MCLA-129, an anti-EGFR/c-MET bispecific antibody, in non-small-cell lung cancer (NSCLC) with c-MET exon 14 skipping mutations (METex14)
Abstract #: 8583
Session Title: Lung Cancer—Non-Small Cell Metastatic
Session Date and Time: June 3, 2024, 1:30-4:30 p.m. CT

The presentation concerns MCLA-129 evaluated as monotherapy in patients with locally advanced/metastatic METex14 NSCLC.

The abstracts will be available on the ASCO website on May 23, 2024 at 5:00 p.m. ET. The full presentations will be available on the Merus website at the start of each session.

About Petosemtamab

Petosemtamab, or MCLA-158, is a bispecific Biclonics^® low-fucose human full-length IgG1 antibody targeting the epidermal growth factor receptor (EGFR) and the leucine-rich repeat containing G-protein-coupled receptor 5 (LGR5). Petosemtamab is designed to exhibit three independent mechanisms of action including inhibition of EGFR-dependent signaling, LGR5 binding leading to EGFR internalization and degradation in cancer cells, and enhanced antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) activity.

About MCLA-145

MCLA-145 is a Biclonics^® T-cell agonist that binds with high affinity and specificity to human PD-L1 and CD137 in preclinical models. The unique immunostimulatory profile of MCLA-145 derives from the potential to potently activate immune effector cells in the context of the tumor microenvironment while blocking inhibitory signals among T-cells within the same immune cell population.

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 NSCLC 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, X, and LinkedIn.

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 clinical development of petosemtamab, MCLA-145 and MCLA-129, future clinical trial results or interim data, clinical activity and safety profile in the on-going trials and planned abstracts and presentation. These forward-looking statements are based on management’s current expectations. 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 Biclonics^®, Triclonics^® and multispecific 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 market volatility; 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; and our registered or unregistered trademarks or trade names may be challenged, infringed, circumvented or declared generic or determined to be infringing on other marks.

These and other important factors discussed under the caption “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2023 filed with the Securities and Exchange Commission, or SEC, on February 28, 2024, 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.

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