Immuneering to Present Molecular Data at 2026 AACR Annual Meeting from Atebimetinib-Treated Patients, Highlighting Mechanism Designed to Improve Durability and Survival

Rhea-AI Summary

Immuneering (Nasdaq: IMRX) will present molecular data at the AACR Annual Meeting (April 17-22, 2026) on April 20, 2026, reporting ctDNA analysis from ≥64 patients with RAS-mutant solid tumors treated with atebimetinib. The company says acquired MAPK pathway alterations were rarely seen, suggesting deeper, more durable MEK inhibition.

Poster 1873 (Poster Section 19) details how Deep Cyclic MEK inhibition aims to limit adaptive and acquired MAPK-axis resistance; the abstract will be on AACR and the poster on Immuneering’s publications page after presentation.

Key Figures

Patients in ctDNA analysis: ≥64 patients AACR meeting dates: April 17–22, 2026 Poster session date: April 20, 2026 +1 more

4 metrics

Patients in ctDNA analysis ≥64 patients RAS-mutant solid tumors treated with atebimetinib in molecular poster

AACR meeting dates April 17–22, 2026 American Association for Cancer Research Annual Meeting schedule

Poster session date April 20, 2026 Atebimetinib molecular data poster session date at AACR

Poster session time 9:00 AM – 12:00 PM ET AACR poster session window for atebimetinib data

Market Reality Check

Price: $4.78 Vol: Volume 1,553,320 is 2.04x...

high vol

$4.78 Last Close

Volume Volume 1,553,320 is 2.04x the 20-day average of 759,844, indicating elevated trading activity ahead of the AACR data poster. high

Technical Shares at $4.80 are trading below the 200-day MA at $5.26, and about 52.38% under the 52-week high of $10.08 while still well above the $1.10 52-week low.

Peers on Argus

IMRX fell 1.78% on high volume while key biotech peers showed mixed performance:...

1 Up

IMRX fell 1.78% on high volume while key biotech peers showed mixed performance: RCKT (-4.54%), TECX (-2.72%), ASMB (-0.94%), FULC (0%), and LRMR appeared in a momentum scan moving up 1.60%. This pattern points to stock-specific trading rather than a coordinated sector move.

Historical Context

5 past events · Latest: Mar 06 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Mar 06	Earnings & update	Positive	+7.0%	Reported 2025 results, 64% 12-month OS, $217M cash and runway to 2029.
Mar 02	Conference appearance	Neutral	-1.0%	Announced participation at Leerink Global Healthcare Conference with webcast plans.
Feb 18	Conference appearance	Neutral	+4.4%	Disclosed presentation at Oppenheimer healthcare conference with investor meetings.
Jan 07	Clinical data update	Positive	-43.2%	Released Phase 2a pancreatic data with 64% 12-month OS and strong efficacy profile.
Dec 23	Data preview notice	Positive	+8.1%	Announced upcoming 12-month OS data webcast for atebimetinib + mGnP trial.

Pattern Detected

Recent clearly positive clinical and earnings updates often produced strong but inconsistent reactions, including one sharp selloff on favorable trial data, suggesting event-driven but sometimes contrarian trading around IMRX news.

Recent Company History

Over the past several months, Immuneering has repeatedly highlighted atebimetinib’s potential. On Jan 7, 2026, it reported Phase 2a pancreatic cancer data with 64% 12-month OS and other supportive efficacy metrics, yet the stock fell 43.22%. A Dec 23, 2025 announcement of upcoming survival data saw an 8.12% gain. The Mar 6, 2026 earnings/clinical update, including $217.0M cash and runway into 2029, was followed by a 7.03% rise. Conference appearances in February–March produced smaller, mixed moves, framing today’s AACR molecular poster as another step in an ongoing atebimetinib narrative.

Regulatory & Risk Context

Active S-3 Shelf · $300,000,000

Shelf Active

Active S-3 Shelf Registration 2025-08-13

$300,000,000 registered capacity

An effective Form S-3 shelf registered up to $300,000,000 of securities, including an equity distribution agreement covering up to $100,000,000 of Class A common stock within that total. The shelf, filed on Aug 13, 2025, provides flexibility for future financings and has been used at least twice via 424B5 prospectus supplements in Sep 2025.

Market Pulse Summary

This announcement details an AACR 2026 poster analyzing ctDNA from ≥64 RAS-mutant solid tumor patien...

Analysis

This announcement details an AACR 2026 poster analyzing ctDNA from ≥64 RAS-mutant solid tumor patients treated with atebimetinib, highlighting a mechanism designed to limit MAPK-pathway resistance. It fits into a broader story that already includes Phase 2a pancreatic data with 64% 12‑month OS and a planned Phase 3 MAPKeeper 301 trial. Investors may monitor how these molecular findings connect with upcoming clinical milestones and how Immuneering uses its $300M shelf flexibility alongside reported cash runway into 2029.

Key Terms

circulating tumor DNA, ctDNA, raf, mek, +1 more

5 terms

circulating tumor DNA medical

"Immuneering will present an analysis of circulating tumor DNA (ctDNA) from ≥64 patients"

Fragments of DNA shed by cancer cells into the bloodstream that act like tiny fingerprints of a tumor; they can be detected with a blood test rather than a biopsy. Investors care because circulating tumor DNA (ctDNA) enables faster, lower-cost ways to detect disease, track treatment response, identify emerging resistance and enroll patients in trials—factors that can materially affect the commercial prospects of diagnostics and therapeutics.

ctDNA medical

"analysis of circulating tumor DNA (ctDNA) from ≥64 patients with RAS-mutant solid tumors"

Circulating tumor DNA (ctDNA) is tiny fragments of genetic material shed by cancer cells into the bloodstream, like breadcrumbs that can reveal a tumor’s presence and genetic makeup without needing a biopsy. For investors, ctDNA matters because tests and technologies that detect and analyze these fragments can speed diagnosis, track treatment response, and signal relapse, creating commercial opportunities in diagnostics, personalized therapies, and monitoring services.

raf medical

"Inhibitors of RAS, RAF, or MEK often provide only temporary benefit due to resistance"

A Risk Adjustment Factor (RAF) is a numerical score used by health insurers and government programs to estimate how much medical care a person is likely to need; it adjusts payments to reflect the expected cost of covering that person. Think of it as a personalized price tag that helps insurers get paid more for sicker members and less for healthier ones. Investors watch RAFs because changes in average scores directly affect revenue predictability, margins, and the financial risks insurers face when enrollments shift toward higher- or lower-risk patients.

mek medical

"Atebimetinib, a novel Deep Cyclic Inhibitor of MEK, is engineered to mitigate"

MEK (methyl ethyl ketone) is a common industrial solvent used to dissolve paints, coatings, adhesives and some plastics, similar to how gasoline thins oil. Investors care because MEK’s availability, price and regulatory status affect manufacturing costs, product quality and environmental or safety liabilities for companies that use or produce it; shifts in supply, regulation or handling rules can change profit margins or require costly compliance steps.

mapk pathway medical

"mechanisms of escape within the MAPK pathway. Atebimetinib, a novel Deep Cyclic Inhibitor"

A MAPK pathway is a chain of proteins inside cells that passes signals from the cell surface to the nucleus to control key behaviors like growth, division and survival; think of it as a relay race where each runner (protein) activates the next to produce a specific response. Investors care because drugs or tests that alter this pathway can change the course of diseases such as many cancers and inflammatory conditions, affecting drug trial outcomes, regulatory risk, and the commercial value of biotech assets.

AI-generated analysis. Not financial advice.

NEW YORK, March 17, 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 it will present a poster on one of the three key mechanisms by which atebimetinib aims to improve overall survival: shrinking tumors durably. The poster will be presented at the American Association for Cancer Research (AACR) Annual Meeting taking place April 17-22, 2026 in San Diego, CA.

Inhibitors of RAS, RAF, or MEK often provide only temporary benefit due to resistance, as tumors acquire new mutations or mechanisms of escape within the MAPK pathway. Atebimetinib, a novel Deep Cyclic Inhibitor of MEK, is engineered to mitigate the selective pressure that typically drives these resistance mechanisms, with the goal of more durable anti-tumor activity. Immuneering will present an analysis of circulating tumor DNA (ctDNA) from ≥64 patients with RAS-mutant solid tumors treated with atebimetinib, showing that acquired MAPK pathway alterations are rarely seen in patients treated with atebimetinib. These findings suggest that Deep Cyclic Inhibitors have the potential to overcome the limitations of conventional MAPK inhibition and provide a more sustained clinical benefit for patients.

Poster Presentation Details:
Title: Atebimetinib’s Deep Cyclic Inhibition of MEK Constrains MAPK-Axis Adaptive and Acquired Alterations in Patients with RAS-Mutant Tumors
Session Category: Experimental and Molecular Therapeutics
Session Title: Targeting Drug Resistance 2: RAS Signaling
Poster Number: 1873
Poster Board Number: 6
Session Date: April 20, 2026
Session Time: 9:00 AM – 12:00 PM ET
Location: Poster Section 19

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

About Immuneering

Immuneering is a late-stage clinical oncology company focused on keeping cancer patients alive and helping them thrive. 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, including MAPK pathway-driven tumors such as pancreatic cancer. The company expects to dose the first patient in mid-2026 in MAPKeeper 301, a globally randomized pivotal Phase 3 trial evaluating atebimetinib in combination with chemotherapy in first-line pancreatic cancer patients. The Company’s development pipeline also includes additional combination opportunities and 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 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 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 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 period ended December 31, 2025, 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
Cdugan@immuneering.com

Media Contact:
Gina Nugent
Gina.nugent.external@immuneering.com

FAQ

What data will IMRX present about atebimetinib at the AACR Annual Meeting on April 20, 2026?

Immuneering will present ctDNA analysis from ≥64 RAS-mutant patients treated with atebimetinib, showing few acquired MAPK alterations. According to the company, the data suggest Deep Cyclic MEK inhibition may constrain adaptive and acquired MAPK-axis changes linked to resistance.

When and where is Immuneering (IMRX) presenting the atebimetinib poster at AACR 2026?

Immuneering will present Poster 1873 on April 20, 2026, from 9:00 AM–12:00 PM ET in Poster Section 19. According to the company, the presentation is part of the "Targeting Drug Resistance 2: RAS Signaling" session.

What does the ctDNA finding from ≥64 patients mean for IMRX's atebimetinib program?

The ctDNA analysis reportedly found that acquired MAPK pathway alterations were rarely seen in treated patients. According to the company, this finding supports the idea that Deep Cyclic MEK inhibition could deliver more durable anti-tumor activity versus conventional MAPK inhibitors.

Will the atebimetinib poster and abstract be publicly available after AACR 2026?

Yes — the abstract will be posted on the AACR website and the poster will be available in Immuneering’s publications section after the presentation. According to the company, the poster will appear on their publications page following the session.

What is the title and session category for Immuneering’s AACR poster on atebimetinib (IMRX)?

The poster is titled "Atebimetinib’s Deep Cyclic Inhibition of MEK Constrains MAPK-Axis Adaptive and Acquired Alterations." According to the company, it appears in the Experimental and Molecular Therapeutics category under Targeting Drug Resistance 2: RAS Signaling.