Merus, a clinical-stage oncology company developing innovative, full-length multispecific antibodies (Biclonics and Triclonics) for cancer, announced that the US Food and Drug Administration (FDA) has granted Orphan Drug Designation to Zenocutuzumab (Zeno) for the treatment of patients with pancreatic cancer.
Zeno is a first in class bispecific antibody that potently binds to the HER2 and HER3 receptors, to potently block the interaction of HER3 with its ligand, neuregulin 1 (NRG1). Zeno has demonstrated promising early clinical responses in patients with previously treated pancreatic cancer harboring NRG1 gene fusions, as presented at the AACR/NCI/EORTC International Conference on Molecular Targets and Cancer Therapeutics in October 2019. The NRG1 gene fusion is a rare, powerful driver of cancer cell growth found in pancreatic, lung and other types of solid tumors. Zeno is now being evaluated in a global phase 1/2 clinical trial called the eNRGy trial.
“Receiving Orphan Drug Designation for Zeno is another important milestone for our lead program, and it validates the significant unmet need in patients with pancreatic cancer,” said Bill Lundberg, M.D., president, chief executive officer and principal financial officer of Merus. “We are pleased with the progress we are making in our ongoing global clinical trial, and believe that Zeno has the potential to play a significant role in shifting the treatment paradigm for NRG1 fusion cancers from conventional chemotherapy to a personalized medicine approach.”
The FDA grants Orphan Drug Designation to drugs that are intended to treat rare diseases that affect fewer than 200,000 people in the US Orphan Drug Designation may provide Merus certain benefits, such as grant funding towards clinical trial costs, tax advantages and eligibility for seven-year market exclusivity.
Pancreatic cancer is estimated to occur in approximately 57,000 patients annually in the United States, according to the NCI SEER database. Pancreatic ductal adenocarcinoma (PDAC), the most common subtype of pancreatic cancer, is one of the most aggressive solid tumor cancers and the fourth leading cause of cancer related deaths.
The NRG1 gene encodes for neuregulin 1 (also known as heregulin), the ligand for HER3. Fusions between NRG1 and partner genes are rare genetic events occurring in patients with certain lung, pancreatic and other solid tumors, associated with activation of HER2/HER3 signaling and growth of cancer cells. NRG1 fusions are estimated to occur at a rate of approximately 0.5% - 1.5% in PDAC, based on the limited available published data.
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. 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+ cancers. In preclinical studies, Zeno also potently inhibits HER2/HER3 heterodimer formation and tumor growth in models harboring NRG1 fusions.
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