• 34% overall response rate in 79 evaluable patients with measurable disease
  • 9.1 months median duration of response
  • Tumor reduction in 70% of patients
  • Zeno observed to be very well-tolerated
  • Potential new standard of care for patients with NRG1+ cancer

UTRECHT, The Netherlands and CAMBRIDGE, MA, USA I June 05, 2022 I 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 interim efficacy data as of an April 12, 2022 data cutoff date, from the phase 1/2 eNRGy trial and Early Access Program (EAP) of the bispecific antibody Zeno in patients with NRG1+ cancer presented virtually by Lead Author, Dr. Alison Schram of Memorial Sloan Kettering Cancer Center (MSKCC) at the 2022 ASCO Annual meeting.

“We have made significant progress with enrollment in the eNRGy trial over the past year,” said Dr. Andrew Joe, Chief Medical Officer at Merus. “And Zeno continues to demonstrate consistent efficacy in patients with multiple types of NRG1+ cancer. We believe Zeno has the potential to be both first in class and best in class as a tumor agnostic treatment for patients with NRG1+ cancer.”

Dr. Schram added, “Zeno has led to durable responses in previously treated NRG1 fusion-positive cancer, with a median duration of response greater than 9 months and more than 25% of those responding continuing at 12 months. Additionally, Zeno has an extremely well tolerated safety profile. There are currently no approved therapies targeting NRG1 fusion-positive cancer and Zeno offers an important, potential new standard of care.”

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 presentation include:

  • As of April 12, 2022, 110 patients were treated with Zeno
  • Efficacy was assessed in 79 evaluable patients with measurable disease having the opportunity for 6 months or more follow-up and who met the criteria for the primary analysis population
  • Median age was 59 years (range of 22-84); 59% were female
  • Median number of prior lines of systemic therapy was 2, (range of 0-8)
  • Qualifying NRG1 fusions included 26 distinct fusion partners
  • ORR per RECIST criteria as assessed by investigator was 34% (95% Cl; 24%-46%) across multiple tumor types
    • PDAC ORR 42% (8/19)
    • NSCLC ORR 35% (16/46)
  • Tumor shrinkage was observed in 70% of patients
  • Median time to response was 1.8 months, and median duration of exposure was 6.3 months
  • Median duration of response was 9.1 months, and 20/83 patients were continuing treatment as of the cutoff date
  • Strong safety profile with a low incidence of Grade 3 or higher treatment-related adverse events, including low rates of severe gastrointestinal and dermatologic toxicity, without clinically significant cardiotoxicity

The full presentation is available on the Publications page of our website.

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+ cancer. 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.