Broad response demonstrated through deep cyclic inhibition of MAPK pathway, independent of specific RAS mutation Phase 1/2a clinical trial with IMM-1-104 underway in patients with advanced solid tumors harboring RAS mutations CAMBRIDGE, Mass., March 05, 2023 (GLOBE NEWSWIRE) — Immuneering Corporation (Nasdaq: IMRX), a clinical-stage oncology company developing medicines for broad populations of cancer patients with an initial aim to develop a universal-RAS therapy, announced today that it will be presenting preclinical data on its lead program IMM-1-104 at the American Association for Cancer Research (AACR) special conference targeting RAS, held March 5-8, 2023, in Philadelphia. The data shows response to IMM-1-104 across a diverse panel of RAS mutant preclinical models, regardless of mutation position or amino acid substitution, suggesting potential relevance to a broad RAS-driven patient population. “We are excited to share these preclinical data that support the universal-RAS activity of IMM-1-104 through its novel target engagement mechanism combined with deep cyclic inhibition,” said Brett Hall, Ph.D., Chief Scientific Officer of Immuneering. “These results further demonstrate the rationale for the unique design of our Phase 1/2a clinical trial with IMM-1-104, which is enrolling patients with advanced solid tumors harboring RAS mutations.” The poster presentation at AACR special conference targeting RAS highlights the following preclinical data: Across all RAS-mutant models tested (132 tumor models, 75 of which have a reported RAS mutation), at least one model displayed response to IMM-1-104 for each observed RAS mutation, regardless of mutation position or amino acid substitution.No significant preference was observed with respect to response to IMM-1-104 across 30 KRAS G12 mutated cell lines, the most commonly mutated position in KRAS, from three major cancer indications including pancreatic, lung and colorectal cancer models. Title: Pan-RAS IMM-1-104 activity in humanized 3D tumor models is independent of specific amino acid substitution Date: Tuesday, March 7, 2023, 4:45 – 7:00p.m. ET Poster session: BAbstract Number: B021 The poster will be available on the publications section of Immuneering’s website at https://immuneering.com/publications/. About IMM-1-104 IMM-1-104 aims to achieve universal-RAS activity that selectively impacts cancer cells to a greater extent than healthy cells, through deep cyclic inhibition of the MAPK pathway with once-daily dosing. IMM-1-104 is currently being evaluated in a Phase 1/2a study in patients with advanced solid tumors harboring RAS mutations (NCT05585320). About Immuneering Corporation Immuneering is a clinical-stage oncology company developing medicines for broad populations of cancer patients with an initial aim to develop a universal-RAS therapy. The company aims to achieve universal activity through deep cyclic inhibition of the MAPK pathway, impacting cancer cells while sparing healthy cells. Immuneering’s lead product candidate, IMM-1-104, is in a Phase 1/2a study in patients with advanced solid tumors harboring RAS mutations. The company’s development pipeline also includes IMM-6-415, our universal-MAPK inhibitor, as well as several early-stage programs. For more information, please visit www.immuneering.com. Forward-Looking Statements This press release includes certain disclosures that contain “forward-looking statements,” including, without limitation, statements regarding Immuneering’s expectations regarding the treatment potential of IMM-1-104, the design, enrollment criteria and conduct of the Phase 1/2a clinical trial, including the unique design of enrolling patients with advanced solid tumors harboring a RAS mutation, the translation of preclinical data into human clinical data, statements regarding Immuneering’s financial guidance and Immuneering’s ability to advance its pipeline and further diversify its portfolio and make progress towards its longstanding goal of creating better medicines for cancer patients. Forward-looking statements are based on Immuneering’s current expectations and are subject to inherent uncertainties, risks and assumptions that are difficult to predict. Factors that could cause actual results to differ include, but are not limited to, the risks inherent in oncology and neuroscience drug research and development, including target discovery, target validation, lead compound identification, lead compound optimization, preclinical studies and clinical trials. These and other risks and uncertainties are described more fully in the section titled “Risk Factors” in Immuneering’s most recent Form 10-Q filed with the U.S. Securities and Exchange Commission. Forward-looking statements contained in this announcement are made as of this date, and Immuneering undertakes no duty to update such information except as required under applicable law. Media Contact: Gina Nugent Nugent Communications 617-460-3579 gina@nugentcommunications.com Investor Contact: Laurence Watts Gilmartin Group 619-916-7620 laurence@gilmartinir.com