On June 11, 2026 Immuneering Corporation (Nasdaq: IMRX), a late-stage clinical oncology company focused on keeping cancer patients alive and helping them thrive, reported that the first patient has been dosed in MAPKeeper 301, a global, randomized, open-label pivotal Phase 3 clinical trial evaluating atebimetinib plus modified gemcitabine/nab-paclitaxel (mGnP) in first-line metastatic pancreatic cancer patients. Atebimetinib is a novel MEK inhibitor with a pulsatile mechanism designed to target RAS, RAF, and other MAPK pathway-driven cancers with greater durability and tolerability than traditional chronic inhibitors.
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"Pancreatic cancer remains a challenging malignancy to treat," said Eileen M. O’Reilly, MD, FASCO, Winthrop Rockefeller Endowed Chair in Medical Oncology at Memorial Sloan Kettering Cancer Center, and the lead principal investigator of the MAPKeeper 301 study. "There is an urgent need for new first-line treatment options that can improve treatment outcomes by augmenting survival and improving quality of life. The MAPKeeper 301 trial evaluating atebimetinib with standard of care therapy represents an exciting step toward addressing that need."
The global MAPKeeper 301 trial (NCT07562152) is evaluating the safety and efficacy of atebimetinib + mGnP in patients with metastatic pancreatic ductal adenocarcinoma (PDAC) who have received no prior systemic anti-cancer therapy. Patients are being randomized to receive either atebimetinib + mGnP, or standard GnP treatment alone. The primary endpoint is overall survival (OS) of patients in the atebimetinib + mGnP arm versus patients in the GnP arm. Key secondary endpoints include progression free survival (PFS), overall response rate (ORR), disease control rate (DCR), safety and tolerability, and quality of life.
"The dosing of the first patient in our pivotal Phase 3 trial is a significant milestone for Immuneering and, more importantly, patients with pancreatic cancer and their families," said Ben Zeskind, PhD, CEO of Immuneering. "Global interest in MAPKeeper-301 has been overwhelming, largely driven by our highly encouraging survival and tolerability data presented earlier this year. We look forward to initiating more sites and dosing more patients as expeditiously as possible with topline data from the pivotal trial expected in mid-2028."
More information about the MAPKeeper 301 trial can be found at www.clinicaltrials.gov, identifier NCT07562152 or the MAPKeeper 301 clinical trial microsite at View Source
About Pancreatic Ductal Adenocarcinoma (PDAC)
According to the National Health Institute, PDAC is the most common and highly lethal form of pancreatic cancer with nearly 68,000 new cases estimated for 2026 in the U.S. alone. Often diagnosed too late, PDAC currently carries a poor prognosis with a five-year survival rate of approximately 13%. Atebimetinib targets MEK in the MAPK pathway, from which 90% of PDAC cases grow and thrive, and is designed to shrink tumors durably with less resistance, optimize tolerability and counteract cachexia, enabling patients to live longer, stay strong and thrive.
(Press release, Immuneering, JUN 11, 2026, View Source [SID1234666594])