• Dosing of the first patient in the Phase 1/2a clinical trial of IMM-6-415 expected in March 2024: The Phase 1 portion of the open-label trial is designed to evaluate the safety, tolerability, PK, and PD of IMM-6-415, as well as identify a candidate RP2D. The Phase 2a portion of the trial will further evaluate safety, tolerability, pharmacokinetics and clinical activity of IMM-6-415, all in patients with advanced solid tumors harboring RAF or RAS mutations. The Phase 1 portion of the clinical trial, which may enroll up to approximately 60 patients, will evaluate IMM-6-415 following a Bayesian mTPI-2 escalation design. Following the Company’s selection of the RP2D candidate, the Company expects to conduct a Phase 2a dose expansion phase in approximately 180 patients in multiple dose expansion arms.

• Presented preclinical data demonstrating encouraging anti-tumor activity for IMM-1-104 and IMM-6-415: In October 2023, Immuneering presented preclinical data at AACR-NCI-EORTC. Expanded benchmarking of IMM-1-104 as a single agent across 193 patient-aligned models in humanized 3D-tumor growth assays demonstrated high sensitivity in a wide range of MAPK-driven tumors, including melanoma, pancreatic cancer and lung cancer. IMM-1-104 in combination with gemcitabine or paclitaxel drove enhanced anti-tumor activity in humanized 3D-tumor growth assays across multiple pancreatic cancer models. Benchmarking of IMM-6-415 as a single agent across more than 60 patient-aligned models in humanized 3D-tumor growth assays demonstrated high sensitivity in a wide range of MAPK-driven tumors, including models of RAS and RAF mutant disease. IMM-6-415 in combination with encorafenib drove deeper regressions and superior durability compared to binimetinib plus encorafenib in a head-to-head study in animal models of RAF mutant melanoma and colorectal cancer.

• Completed dose escalation of the Phase 1 portion of the Phase 1/2a clinical trial evaluating IMM-1-104 for RAS-mutant, advanced solid tumors: In June 2023, the trial’s Safety Review Committee (SRC) completed its evaluation and observed that doses up to and including 320 mg once daily were tolerated with no dose-limiting toxicities. The dose evaluation portion of the trial was designed to evaluate two dosing cohorts of approximately 20 patients each at an oral dose of 240mg or 320mg once daily.

• Raised $30 million in an underwritten offering: In April 2023, Immuneering completed an underwritten offering of 2,727,273 shares of its Class A common stock at an offering price of $11.00 per share. The aggregate net proceeds received by the Company from the offering were $28.2 million, after deducting underwriting discounts and commissions, but before deducting offering expenses payable by Immuneering.

• Reported positive initial Phase 1 PK, PD, and safety data for IMM-1-104: In April 2023, Immuneering presented initial Phase 1 PK, PD, and safety data for IMM-1-104 at the American Association for Cancer Research (AACR) annual meeting. IMM-1-104 achieved significant levels of PK Cmax, demonstrated a half-life of approximately two hours, as predicted, and was well tolerated with no dose-limiting toxicities. These data support the potential of IMM-1-104 to drive deep cyclic inhibition of the MAPK pathway.

Near-Term Milestone Expectations

IMM-1-104

• Topline data from the Phase 1 portion of the Phase 1/2a clinical trial expected in March 2024. The update is expected to include data on the primary and secondary endpoints of the Phase 1 portion of the Phase 1/2a study (tolerability, candidate RP2D, and PK), as well as PD, ctDNA, and initial clinical activity data.

• First patient expected to be dosed in the Phase 2a portion of the Phase 1/2a trial in March 2024.

• Initial data from multiple Phase 2a arms expected in 2024.

• Additional trial updates expected on a periodic basis.

IMM-6-415

• First patient expected to be dosed in the Phase 1 portion of the Phase 1/2a trial in March 2024.

Fourth Quarter and Full Year 2023 Financial Highlights

• Cash Position: Cash, cash equivalents and marketable securities as of December 31, 2023 were $85.7 million, compared with $105.5 million as of December 31, 2022.

• Research and Development (R&D) Expenses: R&D expenses for the fourth quarter of 2023 were $11.9 million compared with $9.9 million for the fourth quarter of 2022. Full year 2023 R&D expenses were $41.6 million compared to $36.3 million for full year 2022. The increase in R&D expenses from both periods of 2023 was primarily attributable to higher clinical costs related to the Company’s lead program and increased personnel to support ongoing research and development activities.

• General and Administrative (G&A) Expenses: G&A expenses for the fourth quarter of 2023 were $4.4 million compared with $4.1 million for the same period of 2022. Full year 2023 G&A expenses were $16.8 million compared to $15.6 million for full year 2022. The increase in G&A expenses for both periods of 2023 was primarily attributable to an increase in headcount in the Company’s general and administrative functions to support the business, and costs related to operating as a public company.

• Net Loss: Net loss attributable to common stockholders was $15.1 million, or $0.52 per share, for the quarter ended December 31, 2023, compared to $13.2 million, or $0.50 per share, for the quarter ended December 31, 2022. Net loss attributable to common stockholders for full year 2023 was $53.5 million, or $1.88 per share compared to $50.5 million, or $1.91 per share, for full year 2022.

2024 Financial Guidance

• Based on cash, cash equivalents and marketable securities, as of December 31, 2023, and current operating plans, the Company expects its cash runway to be sufficient to fund operations into the second half of 2025.

About Immuneering Corporation

Immuneering is a clinical-stage oncology company seeking to develop and commercialize universal-RAS/RAF medicines for broad populations of cancer patients. 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 an oral, once-daily deep cyclic inhibitor currently in a Phase 1/2a study in patients with advanced solid tumors harboring RAS mutations. IMM-6-415 is an oral, twice-daily deep cyclic inhibitor and will be evaluated in a Phase 1/2a study in patients with advanced solid tumors harboring RAS or RAF mutations. The Company’s development pipeline also includes several early-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 concerning: the expected design, timing, enrollment and advancement of, and data results from, preclinical studies and clinical trials involving our product candidates; the potential of our product candidates to be used as monotherapies and / or in combination with other therapeutic agents, including to treat RAS or RAF mutant diseases; our expected cash runway; and the clinical development of IMM-1-104 and IMM-6-415.

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 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 Annual Report on Form 10-K for the annual period ended December 31, 2023, and our other reports filed with the United States 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.

Media Contact:
Gina Nugent
Nugent Communications
617-460-3579
gina@nugentcommunications.com

Investor Contacts:
Laurence Watts
Gilmartin Group
619-916-7620
laurence@gilmartinir.com

or

Kiki Patel, PharmD
Gilmartin Group
332-895-3225
kiki@gilmartinir.com