Immuneering Comments on Today’s FDA Approval in Second-Line Metastatic Pancreatic Cancer, Reiterates Focus on First-Line Patients

- For patients with second-line (2L) metastatic pancreatic cancer, today’s FDA approval of a new treatment is an important milestone –

- For patients with first-line (1L) metastatic pancreatic cancer, Immuneering’s atebimetinib is being evaluated in a global randomized Phase 3 trial, MAPKeeper 301 –

- 17.3-month median overall survival previously reported from Immuneering’s Phase 2a study of atebimetinib plus modified gemcitabine/nab-paclitaxel (mGnP) in 1L pancreatic cancer -

- In the same Phase 2a study, the only Grade 3+ treatment-related adverse events in ≥10% of patients were anemia (16%) and neutropenia (18%), both chemotherapy-related -

NEW YORK, Aug. 26, 2026 (GLOBE NEWSWIRE) -- Immuneering Corporation (Nasdaq: IMRX), a late-stage clinical oncology company focused on keeping cancer patients alive and helping them thrive, today shared comments following the recent FDA approval of a new second-line pancreatic cancer treatment.

“Approval of this new treatment is good news for the subset of pancreatic cancer patients who have received at least one prior systemic therapy or who are not candidates for multiagent systemic therapy,” said Ben Zeskind, Ph.D., CEO of Immuneering. “The top priority for the pancreatic cancer field now turns to the development of treatments for first-line metastatic pancreatic cancer patients. Immuneering is focused on treating these patients, and our Phase 3 MAPKeeper 301 study is enrolling them now. Atebimetinib is designed to help cancer patients live longer through a balance of attacking tumors and protecting patients. From the beginning, we have sought to control disease in parallel with maintaining body weight and minimizing harsh side effects such as rash, diarrhea, stomatitis, and fatigue. Our goal is to give first-line pancreatic cancer patients a choice that can help them live long, stay strong, and feel well.”

MAPKeeper 301 ( NCT07562152) is a global, randomized pivotal trial evaluating atebimetinib in combination with chemotherapy in patients with first-line metastatic pancreatic cancer. More than 35 trial locations are already listed on ClinicalTrials.gov.

As previously reported, Immuneering's open-label, single-arm Phase 2a trial achieved 17.3 months median overall survival in 55 first-line metastatic pancreatic cancer patients treated with atebimetinib 320 mg once daily plus modified gemcitabine/nab-paclitaxel (mGnP), as of the April 24, 2026 data cutoff, with median follow-up of 11.6 months. Notably, 84% of evaluable patients maintained or gained weight at three months. The only treatment-related adverse events observed at Grade 3 or higher in ≥10% of patients were anemia (16%) and neutropenia (18%), both chemotherapy-related.

About Immuneering Corporation

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 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 dosing and preliminary readout of the planned Phase 2 lung cancer trial and the Phase 3 topline readout of the MAPKeeper 301 trial; the timing of beginning IND-enabling studies in a second DCI program; our operating plans and anticipated cash runway, and the potential ability of the three design mechanisms of atebimetinib to shrink tumors durably, improve overall survival and overcome the limitations of conventional MAPK inhibition 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: we are a late-stage clinical oncology company with a limited operating history and have not completed any registrational clinical trials; we have incurred significant losses, are not currently profitable and may never become profitable; limitations on our cash runway and potential increases in expenditures; our need for additional funding; our unproven approach to therapeutic intervention; our ability to address regulatory questions and changing regulatory standards, and the uncertainties relating to regulatory filings, reviews and approvals; the lengthy, expensive, and uncertain process of clinical drug development, including the uncertainty of whether positive preclinical or early clinical efficacy and safety results are confirmed in later-stage trials, 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 June 30, 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:

Laurence Watts

New Street Investor Relations

laurence@newstreetir.com

Media Contact:

David Caouette

dcaouette@immuneering.com