Immuneering Announces First Patient Dosed in Pivotal Phase 3 MAPKeeper 301 Trial of Atebimetinib + mGnP in First-Line Pancreatic Cancer
Global pivotal Phase 3 trial will evaluate efficacy and safety of atebimetinib + modified gemcitabine/nab-paclitaxel (mGnP) compared to standard GnP alone
Topline data readout, including primary endpoint of overall survival, anticipated in mid-2028
NEW YORK, June 11, 2026 (GLOBE NEWSWIRE) -- Immuneering Corporation (NASDAQ:IMRX), a late-stage clinical oncology company focused on keeping cancer patients alive and helping them thrive, today announced 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.
"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 http://mapkeeper301.com/
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.
About Immuneering
Immuneering is a late-stage clinical oncology company dedicated to keeping cancer patients alive and helping them thrive, with an initial focus on patients with RAS, RAF, and other MAPK-driven cancers. The Company is developing an entirely new category of cancer medicines, Deep Cyclic Inhibitors, designed to improve overall survival by three mechanisms: shrinking tumors durably with less resistance, preserving body mass by countering cachexia, and minimizing side effects to maximize performance status and combinability. Immuneering's lead product candidate, atebimetinib, is an investigational, oral, once-daily Deep Cyclic Inhibitor of MEK, designed to improve survival across many cancer indications. The company is conducting a global randomized pivotal trial, MAPKeeper 301, evaluating atebimetinib in combination with chemotherapy in first-line pancreatic cancer patients. The Company's development pipeline also includes additional combination opportunities and preclinical stage programs. For more information, please visit www.immuneering.com.
Forward-Looking Statements
This press release contains forward-looking statements, including 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 treatment potential of atebimetinib, alone or in combination with other agents to treat cancer, including modified Gemcitabine/nab-paclitaxel (mGnP) in first-line pancreatic cancer and its potential to deliver overall survival with both durability and tolerability; the timing of the topline readout of MAPKeeper 301, the ability of the three design mechanisms of atebimetinib to shrink tumors durably, improve overall survival and overcome the limitations of conventional MAPK inhibition, including to impose less selective pressure, and provide a more sustained clinical benefit for patients.
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: the risks inherent in oncology drug research and development, including target discovery, target validation, lead compound identification, and lead compound optimization; we have incurred significant losses, are not currently profitable and may never become profitable; our projected cash runway; our need for additional funding; our unproven approach to therapeutic intervention; our ability to address regulatory questions and the uncertainties relating to regulatory filings, reviews and approvals; the lengthy, expensive, and uncertain process of clinical drug development, including potential delays in activation of trial sites or enrollment of trial participants, or failure to obtain regulatory approvals; our reliance on third parties and collaborators to conduct our clinical trials, manufacture our product candidates, and develop and commercialize our product candidates, if approved; failure to compete successfully against other drug companies; protection of our proprietary technology and the confidentiality of our trade secrets; potential lawsuits for, or claims of, infringement of third-party intellectual property or challenges to the ownership of our intellectual property; our patents being found invalid or unenforceable; costs and resources of operating as a public company; and unfavorable or no analyst research or reports.
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, 2026, and our other reports filed with the U.S. Securities and Exchange Commission, 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, except as required by law, we disclaim any obligation to do so, even if subsequent events cause our views to change. 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.
Investor Contact:
Courtney Dugan
Cdugan@immuneering.com
Media Contact:
Peg Rusconi
Peg.rusconi@deerfieldgroup.com
