Merus Announces Publication of Abstract of Zenocutuzumab in NRG1-fusion (NRG1+) Cancer at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting

- Robust 34% overall response rate and 9.1 months median duration of response across multiple NRG1+ tumor types

- Zenocutuzumab observed to be well-tolerated

- Oral presentation with additional patient data at ASCO on June 5, 2022, 9:45 -11:15 a.m. CT

- Investor call to discuss clinical results on Sunday, June 5 at 6:00 p.m. CT

UTRECHT, The Netherlands and CAMBRIDGE, Mass., May 26, 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 announced the publication of the abstract highlighting updated interim data from the ongoing phase 1/2 eNRGY trial and Early Access Program (EAP) of the bispecific antibody zenocutuzumab (Zeno) in patients with NRG1 fusion (NRG1+) cancer, on the American Society of Clinical Oncology (ASCO) website. The abstract includes data as of a January 12, 2022 data cutoff date. As of that time, 99 patients with NRG1+ cancer had been treated and efficacy was assessed in 73 patients with the opportunity to have = 6 month follow-up, and that met the criteria for the primary efficacy population. The oral presentation will include updated interim data and will be presented by the Principal Investigator of the eNRGy trial, Dr. Alison Schram of Memorial Sloan Kettering Cancer Center (MSKCC), at the 2022 ASCO Annual Meeting on Sunday, June 5, 2022, 9:45-11:15 a.m. CT.

"We are excited to provide a more mature, interim clinical dataset from the Zeno program and are thrilled that Zeno continues to demonstrate activity across different tumor types,” said Dr. Andrew Joe, Chief Medical Officer at Merus. "We continue to be encouraged by the potential of Zeno to help patients with NRG1+ cancer.”

The reported data are from the phase 1/2 eNRGy trial and EAP which are assessing the safety and anti-tumor activity of Zeno monotherapy in NRG1+ cancer.

Key findings of the abstract include:

• As of January 12, 2022, 99 patients were treated with Zeno. 73 pts who were treated as of July 12, 2021 were evaluable for response and had the opportunity for = 6 months follow-up and met the criteria for the primary efficacy population
  • The investigator-assessed overall responses rate (ORR) by RECIST 1.1. criteria was 34% (90%CI, 25;44)
  • The median duration of response (DOR) was 9.1 months (95% CI, 5.2-12.0) and Kaplan-Meier estimate of DOR rate at 6 month was 70%.
  • Responses were observed in patients with multiple types of NRG1+ cancer
• Zeno continues to be well-tolerated
  

Oral Presentation Details:
Title: Efficacy and safety of zenocutuzumab, a HER2 x HER3 bispecific antibody, in advanced NRG1 fusion-positive (NRG1+) cancers
Lead Author: Alison Schram, MD, Memorial Sloan Kettering Cancer Center, NY
Abstract #: 105
Session Title: Clinical Science Symposium/ Bispecifics: Are Two Better Than One?
Session Date and Time: June 5, 2022, 9:45-11:15 a.m. CT

Company Conference Call and Webcast Information
Merus will hold a conference call and webcast for investors on Sunday, June 5, 2022 at 6:00 p.m. CT to discuss the Zeno clinical data and provide a program update. A replay will be available after the completion of the call in the Investors and Media section of our website for a limited time.

Date: Sunday, June 5, 6:00 p.m. CT
Webcast link: available on our website
Dial-in: Toll-free: 18772601463/ International: 17066435907
Conference ID: 7194538

About the eNRGy Clinical Trial
Merus is currently enrolling patients in the phase 1/2 eNRGy trial to assess the safety and anti-tumor activity of Zeno monotherapy in NRG1+ cancer. The eNRGy trial consists of three cohorts: NRG1+ pancreatic cancer; NRG1+ non-small cell lung cancer; and NRG1+ other solid tumors. Further details, including current trial sites, can be found at www.ClinicalTrials.gov and Merus’ trial website at www.nrg1.com or by calling 1-833-NRG-1234.

About Zeno
Zeno is an antibody-dependent cell-mediated cytotoxicity (ADCC)-enhanced Biclonics^® that utilizes the Merus Dock & Block^® mechanism to inhibit the neuregulin/HER3 tumor-signaling pathway in solid tumors with NRG1 gene fusions (NRG1+ cancer). Through its unique mechanism of binding to HER2 and potently blocking the interaction of HER3 with its ligand NRG1 or NRG1-fusion proteins, Zeno has the potential to be particularly effective against NRG1+ cancer. In preclinical studies, Zeno also potently inhibits HER2/HER3 heterodimer formation and tumor growth in models harboring NRG1 fusions.

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, http://www.merus.nl and https://twitter.com/MerusNV.

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 Zeno, future clinical trial results, clinical activity and safety profile of Zeno in the on-going eNRGy trial and EAP, and potential of Zeno to help patients with NRG1+ cancer. 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 clinical development efforts for marketable drugs; potential delays in enrollment of patients, and our reliance on third parties to conduct our clinical trials, manufacturing and accompanying activities for clinical drug development and potential approval and the potential for those third parties to not perform satisfactorily, which could affect the receipt of necessary regulatory approvals; 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 an support development of 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; 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 Quarterly Report on Form 10-Q for the period ended March 31, 2022 filed with the Securities and Exchange Commission, or SEC, on May 9, 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.