Immuneering Presents Data at 2026 AACR Conference on Pancreatic Cancer Supporting Atebimetinib’s Mechanisms Designed to Extend Survival in Pancreatic Cancer

- Stable or increased weight was twice as common among pancreatic cancer patients in the atebimetinib + mGnP study, compared to those in a benchmark study -

- Patients with stable or increased weight at three months had significantly longer overall survival than patients who lost weight at three months -

- Overall survival was comparable among patients with moderate and deeper tumor volume reductions, suggesting presence of tumor reduction may be more important than depth of response -

- Findings support atebimetinib’s mechanisms designed to extend survival including tumor volume reduction and body mass preservation -

NEW YORK, Sept. 28, 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 the presentation of new data at the 2026 AACR Conference on Pancreatic Cancer in San Diego, California. The findings, presented by Peter Vu, M.D., MHA, UC San Diego Health, support a potential dual mechanism of action through which atebimetinib may improve survival in pancreatic cancer by both reducing tumor volume and preserving body mass.

“We designed atebimetinib to do several important things at the same time: to shrink tumors and to counteract the tumor-driven weight loss (known as cachexia) that harms many cancer patients, all while minimizing side effects,” said Ben Zeskind, Ph.D., Co-founder and Chief Executive Officer of Immuneering. “We already reported that 84% of evaluable patients treated with atebimetinib + mGnP have stable or increasing weight. Now we can add that these pancreatic cancer patients in our study were twice as likely to have stable or increasing weight as those in a benchmark study, and the patients in our study with stable or increasing weight had longer overall survival than those who lost weight. We believe reduction in tumor volume, maximization of tolerability, and preservation of body mass all contributed to the compelling 17.3-month median overall survival we reported at ASCO 2026 in 55 first-line pancreatic cancer patients treated with atebimetinib + mGnP in our Phase 2a study. We are excited to now be evaluating atebimetinib + mGnP in our ongoing Phase 3 MAPKeeper 301 clinical trial, which is actively enrolling first-line pancreatic cancer patients.”

"Cachexia is an especially important problem in pancreatic cancer and can have a profound impact on patients' survival and quality of life," said Peter Vu, M.D., MHA, UC San Diego Health and lead author of the poster. "In this exploratory analysis, patients who maintained their weight at three months had longer overall survival than those who lost weight, and two-thirds of patients with anorexia symptoms at baseline reported improvement while on treatment. Having enrolled a number of patients on this study, I've been encouraged by how well the combination has been tolerated. These findings support further study of whether atebimetinib may benefit patients beyond conventional measures of tumor response, and I'm hopeful the Phase 3 MAPKeeper 301 trial will help define its role as a new treatment option for pancreatic cancer."

The poster, entitled “Atebimetinib Reduces Tumor Volume and Preserves Body Mass: A Dual Mechanism for Extended Survival in Pancreatic Cancer,” evaluated the relationship between body mass preservation, tumor volume reduction and overall survival in first-line pancreatic cancer patients treated with atebimetinib in combination with modified gemcitabine/nab-paclitaxel (mGnP) in a single-arm Phase 2a study, using exploratory, post-hoc analyses with the same data cutoff date as the ASCO presentation (April 24, 2026). Highlights of the data include:

• Median overall survival of 17.3 months was previously reported in 55 first-line pancreatic cancer patients treated with atebimetinib + mGnP, and 84% of evaluable patients had stable or increased weight at three months. In the new analysis presented at AACR Pancreatic Cancer 2026, the proportion of patients demonstrating stable or increasing weight was approximately two-fold higher among atebimetinib + mGnP-treated patients evaluable for weight trajectory analysis (n=23) compared with patients from a published benchmark study (Fuller S, et al, JNCI, 117:8, 2025, 1729–1732, https://doi.org/10.1093/jnci/djaf030). Median weight trajectory stabilized during atebimetinib treatment.
  
• Among first-line pancreatic cancer patients treated with atebimetinib + mGnP, those with stable or increased weight at three months had significantly longer overall survival than patients who experienced weight loss at three months (HR=3.13; p=0.049). Median overall survival had not been reached in the weight-stable or weight-gain group after median follow-up of 15.2 months.
  
• Among patients with low baseline scores of 37 or below on the FAACT-Anorexia Cachexia Subscale (ACS), 66% achieved an improvement of at least four points on this patient-reported outcome while on treatment. These improvements were observed across a range of RECIST responses.
  
• The analysis also evaluated the relationship between tumor volume reduction and overall survival. Overall survival among patients with deeper tumor volume reductions, defined as a sum of longest diameters (SLD) reduction of at least 30%, was comparable to overall survival among patients with moderate tumor volume reductions of between 0% and 30%. Median overall survival was not reached in either group. In contrast, median overall survival was reached among patients without a measured reduction in SLD. The findings suggest that achieving tumor volume reduction may be more important to overall survival than the depth of tumor reduction and that clinically meaningful benefit may extend to patients whose tumor shrinkage does not meet the threshold for a RECIST partial response.
  

Following presentation, the poster will be available on the publications section of Immuneering’s website at https://immuneering.com/publications.

Atebimetinib in combination with mGnP is currently being evaluated in a Phase 3 MAPKeeper 301 clinical trial in patients with first-line pancreatic cancer (NCT07562152).

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); the finding that presence of tumor reduction may be more important than depth of response; atebimetinib’s design mechanisms and the relationship between body mass preservation and tumor volume reduction to extend survival in pancreatic cancer.

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