Zenocutuzumab (MCLA-128) is an investigational drug that has not been approved by the FDA for treatment of cancer.

Do you, someone you know, or a patient you are treating, have cancer with an NRG1 gene fusion? Here you’ll find information about Merus’ clinical trial and Early Access Program (EAP) for an experimental medicine, zenocutuzumab (MCLA-128), for cancer patients with solid tumors with an NRG1 Fusion.

Learn about
NRG1 Fusions &
eNRGy Trial
Learn about
The Science Behind
About NRG1 Fusions and the eNRGy Clinical Trial

Cancer is a genetic disease

Genes are the instructions to make proteins, which carry out important functions in our cells including telling cells when to grow and divide. Cancer is caused by genetic abnormalities; that is, changes (e.g. mutations, deletions, fusions etc.) to certain genes that control the way cells grow and divide. In some cases, these genetic changes cause too much protein to be produced or the protein to deform and function abnormally.

NRG1 Fusions drive cancer in some patients

NRG1 Fusions are genetic abnormalities found in a small percentage of patients with solid tumors. In these patients, too much of the growth factor NRG1 (sometimes called heregulin) may be produced, which is capable of causing cancer cells to grow and divide in an uncontrolled manner. Blocking NRG1 and its cancer-driving activity with a medicine may help fight your cancer.

Small percentages of multiple types of solid tumors have NRG1 Fusions

A recent study1 identified the following tumor types that harbor an NRG1 Fusion: non-small cell lung cancer, gallbladder cancer, renal cell carcinoma, bladder cancer, ovarian cancer, pancreatic cancer, breast cancer, neuroendocrine tumor, sarcoma, and colorectal cancer. A test of a patient’s cancer can be conducted to determine if his or her tumor has an NRG1 Fusion.

Experimental medicine: zenocutuzumab (MCLA-128)

Zenocutuzumab (MCLA-128) is an experimental cancer medicine being studied in a Phase 1/2 clinical trial in cancer patients who have solid tumors that have a specific genetic abnormality called an NRG1 Fusion. Zenocutuzumab (MCLA-128) is believed to work by blocking the protein produced by the NRG1 Fusion that has cancer-driving activity.

At this time, there is no approved therapy for the specific treatment of NRG1 Fusion-positive solid tumors. Zenocutuzumab (MCLA-128) is an intravenous (IV) medication that is given through a tube infused in a vein in a patient’s arm every 2 weeks. The infusion typically lasts from 2-4 hours each time it is administered.

Zenocutuzumab (MCLA-128) is an experimental medicine and it has not yet been approved for sale by any regulatory authority anywhere in the world and has not been determined to be safe and effective for the purpose for which it is under investigation.

The biopharmaceutical company, Merus N.V., is the sponsor of the clinical trials for and developer of zenocutuzumab (MCLA-128). Information can be found at ClinicalTrials.gov.

Talk with your doctor about clinical trials

If interested in participating in a clinical trial, please talk to your physician to discuss if participating in a clinical trial may be an option for the treatment of your cancer. Your doctor can help answer any questions for you about your type of cancer, the clinical trials that might be available to you or other treatments that could be available. Your decision to participate in a clinical trial is voluntary and should only be made after all your questions have been answered and you have been able to make a well-informed decision.

eNRGy Clinical Trial for Zenocutuzumab (MCLA-128)

If you are a patient with a solid tumor with an NRG1 fusion or a physician treating a patient with NRG1 fusion positive cancer, please call 1-833-NRG-1234 for more information about zenocutuzumab (MCLA-128) and the MCLA-128-CL01 clinical trial.

For the eNRGy study of zenocutuzumab (MCLA-128) in cancer patients with NRG1 Fusions, there are more than 20 medical centers around the world that are enrolling patients. The map below provides details about clinical trial locations for the eNRGy study.

For patients with cancer harboring NRG1 fusions that are otherwise unable to participate in an applicable clinical trial, they may be eligible to participate in the Early Access program for zenocutuzumab (MCLA-128).

Clinical Trial Locations

NRG1 Fusion: The Science Behind the eNRGy Clinical Trial

NRG1 Fusions

Different types of cancer can sometimes be distinguished by changes to certain genes. Tumors with certain abnormal changes to a gene may respond differently to cancer treatments.

Certain kinds of alterations in the NRG1 gene are called NRG1 Fusions and may cause increased levels of the growth factor NRG1, which is capable of leading to activation of tumor growth. NRG1 Fusions have been identified in patients with different types of solid tumors, including non-small cell lung cancer (NSCLC), pancreatic cancer, gallbladder cancer, renal cell carcinoma, bladder cancer, ovarian cancer, breast cancer, neuroendocrine tumor, sarcoma, and colorectal cancer.

Cancer Cell Volume 33, Issue 5, May 2018

About Zenocutuzumab (MCLA-128)

Zenocutuzumab (MCLA-128) is an experimental medicine that is believed to work by blocking the action of the growth factor NRG1 – a protein that can be overproduced due to NRG1 Fusions – and prohibiting it from binding to HER3. HER3 is a protein that sits on the surface of cancer cells, which when it combines with a second surface protein HER2, it sends signals to drive tumor growth and survival. NRG1 induces the combination of HER2 and HER3.

Geuijen et al. (2018) Cancer Cell

Zenocutuzumab (MCLA-128) is a bispecific antibody, which means it is able to recognize two different proteins, specifically HER2 and HER3. Zenocutuzumab (MCLA-128) is designed to have a ‘dock and block’ mechanism:

  • First, zenocutuzumab (MCLA-128) docks onto HER2.
  • Then, it is able to block HER3’s ability to bind NRG1.

When zenocutuzumab (MCLA-128) interacts with HER2 and HER3, in preclinical models it has been shown that the growth and survival signal driving NRG1 fusion cancer progression is disrupted.

In addition to its direct action on the cancer cell linking to HER2 and HER3, zenocutuzumab (MCLA-128) is manufactured in a way that aims to increase a patient’s own ability to attack cancer, called antibody-dependent cell-mediated cytotoxicity (ADCC) properties. Zenocutuzumab (MCLA-128) is designed to have enhanced ADCC activity.


For more information about cancer generally and the availability of potential treatments, please visit the following:

American Cancer Society

National Institutes of Health – National Cancer Institute

To learn about clinical trials, please visit the following:



eNRGy Clinical Trial Facts

Trial Description
A Study of Zenocutuzumab (MCLA-128) in Patients With Solid Tumors Harboring an NRG1 Fusion


Abbreviated Eligibility Requirements

  • Be 18 years or older
  • Have a solid tumor harboring the NRG1
    gene fusion
  • All genders

Trial Locations
Asia, Europe, United States, Canada and Israel


  • Pancreatic cancer harboring NRG1
  • Non-small cell lung cancer harboring
    NRG1 fusion
  • Solid tumors harboring NRG1 fusion

Trial Purpose
To assess the magnitude of anti-tumor
activity of zenocutuzumab (MCLA-128) in patients with
NRG1 fusion. (Overall Response Rate)

Participation Questions

Identifier Number(s)
2014-003277-42 (EudraCT #)


Jonna S, Feldman RA, Swensen J, et al. http://clincancerres.aacrjournals.org/content/early/2019/04/13/1078-0432.CCR-19-0160 Detection of NRG1 gene fusions in solid tumors [published online April 15, 2019]. Clin Cancer Res. doi: 10.1158/1078-0432.CCR-19-0160
Definition of a clinical trial:
Clinical trials in cancer are research studies where people volunteer to receive experimental medications to see if they are safe and effective in treating their type of cancer. Information is collected to determine how the medication works and how the patient feels while taking the medication. The information collected on all patients is combined at the end of the study and if the medication is shown to be safe and effective, it could result in the medication being approved for treatment of patients with that type of cancer. For more information about clinical trials, please visit U.S. National Institutes of Health, National Library of Medicine – ClinicalTrials.gov
Definition of Early Access:
A way for patients with serious diseases or conditions who cannot participate in a clinical trial to gain access to a medical product that has not been approved by the U.S. Food and Drug Administration (FDA). Also called expanded access or compassionate use. There are different early access types. For more information generally, see FDA Expanded Access: Information for Patients. And for more information regarding early/expanded access related to zenocutuzumab (MCLA-128) and NRG1 fusion, see https://clinicaltrials.gov/ct2/show/NCT04100694?cond=NRG1+fusion&rank=1
Back to Top

This links to an external website. Merus is not responsible for any third party content.