- Detailed data from 55 patients to be shared in an oral presentation at the ASCO Annual Meeting on June 1, 2026 -

- Tolerability profile consistent with prior updates: only two categories of Grade 3 or higher treatment-related adverse events observed in ≥10% of patients, both chemotherapy-related -

- Company to hold investor conference call on June 1, 2026, at 8:00 a.m. EST -

NEW YORK, May 21, 2026 (GLOBE NEWSWIRE) -- Immuneering Corporation (Nasdaq: IMRX), a late-stage clinical oncology company focused on keeping cancer patients alive and helping them thrive, today reported a 17.3-month median overall survival (OS) in first-line metastatic pancreatic cancer patients treated in its Phase 2a clinical trial evaluating atebimetinib (IMM-1-104) plus modified gemcitabine/nab-paclitaxel (mGnP), as of the April 24, 2026 data cutoff date. 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. The full data (N=55) including details on OS, progression free survival (PFS), response, safety, weight stability/gain, and other relevant information will be shared in an oral presentation at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting by Peter Vu, MD, MHA of UC San Diego Health, on June 1, 2026, at 1:15 p.m. CDT.

“In my own patients on this trial, I have seen meaningful benefit without the functional decline I am accustomed to seeing in this disease — patients holding their weight, their energy, and their sense of themselves across many months of treatment," said Daniel Ahn, D.O., Mayo Clinic Arizona, an investigator on the Phase 2a trial of atebimetinib. "When the field has more than one effective first-line option, the deciding factor at the bedside will be tolerability.”

“A 17.3-month median overall survival is a meaningful result for first-line metastatic pancreatic cancer patients,” said Ben Zeskind, Ph.D., CEO of Immuneering. “Importantly, only two categories of Grade 3 or higher treatment-related adverse events were observed in 10% or more of patients, both chemotherapy-related. These findings support our randomized Phase 3 clinical trial, MAPKeeper 301, which is now recruiting. We look forward to Dr. Vu’s presentation of the full data at ASCO on June 1.”

The company will share data from the expanded cohort totaling 55 first-line patients at ASCO on June 1, 2026, which includes an initial cohort of 34 patients that the company previously reported, plus an additional 21 patients. The company’s pivotal Phase 3 MAPKeeper 301 (NCT07562152) trial of atebimetinib + mGnP in patients with first-line metastatic pancreatic cancer is currently recruiting, and the company is on track to dose the first patient in mid-2026.

Oral Presentation Details:

Title: Results from a phase 2a study of atebimetinib in combination with mGnP in advanced or metastatic pancreatic cancer
Session Type/Title: Rapid Oral Abstract Session – Gastrointestinal Cancer – Gastroesophageal, Pancreatic, and Hepatobiliary
Abstract Number: 4013
Date and Time: June 1, 2026, 1:15 p.m. – 2:45 p.m. CDT
Presenter: Peter Vu, M.D., MHA (UCSD)

Authors: Vincent Chung (City of Hope), Peter Vu (UCSD), Vincent Ma (University of Wisconsin), Nataliya Uboha (University of Wisconsin), Umair Majeed (Mayo Clinic), Su Chandra (Northwestern), Devalingam Mahalingam (Northwestern), Melissa Johnson (Sarah Cannon), Meredith Pelster (Sarah Cannon), Anna Pavlick (Weill Cornell), Allyson Ocean (Weill Cornell), Barbara Ma (Weill Cornell), Alex Spira (NEXT Oncology), Steven Duffy (HOACNY), Jason Henry (Sarah Cannon), Gregory Botta (UCSD), Alexander Philipovskiy (Sarah Cannon), Shubham Pant (MD Anderson), Sant Chawla (Sarcoma Oncology), Jenny Zhang (Immuneering), Jason Kim (Immuneering), Sarah Kolitz (Immuneering), Jason Funt (Immuneering), Vinny Hayreh (Immuneering), Brett Hall (Immuneering), Ben Zeskind (Immuneering), Igor Matushansky (Immuneering), Daniel Ahn (Mayo Clinic)

Conference Call

Immuneering will host a conference call and live webcast at 8:00 a.m. ET / 7:00 a.m. CT on June 1, 2026, to discuss the data. Individuals interested in listening to the live conference call may do so by dialing (800) 715-9871 for U.S callers and (646) 307-1963 for other locations and reference conference ID 7597768, or from the webcast link in the “investors” section of the company's website at www.immuneering.com. A webcast replay will be available in the investor relations section on the company’s website for 90 days following the completion of the call.

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; the timing of dosing of the MAPKeeper 301 study and the phase 2a results supporting such study; the content of the upcoming 2026 oral presentation at ASCO; the 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: 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 activating trial sites or enrolling 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
[email protected]

Media Contact:
Peg Rusconi
[email protected]