Immuneering Presents Compelling 17.3-Month Median Overall Survival and Favorable Tolerability with Atebimetinib + Chemotherapy in First-Line Pancreatic Cancer Patients at ASCO

Rhea-AI Summary

Immuneering (Nasdaq: IMRX) reported updated Phase 2a data for atebimetinib + mGnP in first-line metastatic pancreatic cancer at ASCO 2026. In 55 patients, median overall survival was 17.3 months (95% CI: 11.2, not reached), versus 8.5 months reported for gemcitabine/nab-paclitaxel in the pivotal MPACT study.

Median progression-free survival was 8.3 months, with 82% disease control rate and 36% confirmed overall response rate. Safety findings showed only two categories of Grade ≥3 treatment-related adverse events in ≥10% of patients, both chemotherapy related, and 84% of participants maintained or gained weight at three months.

The global randomized Phase 3 MAPKeeper 301 trial of atebimetinib plus mGnP versus standard gemcitabine/nab-paclitaxel in first-line metastatic pancreatic cancer is actively recruiting, with first patient dosing expected in mid-2026 and topline readout targeted for mid-2028.

Positive

• Median overall survival 17.3 months in 55 first-line metastatic pancreatic cancer patients
• Median progression-free survival 8.3 months with 82% disease control rate
• Confirmed overall response rate of 36% in Phase 2a trial
• Only two Grade ≥3 treatment-related adverse event categories in ≥10% of patients, both chemotherapy related
• No Grade 4 atebimetinib-related events and no Grade 5 treatment-related events reported
• 84% of participants maintained or gained weight at three months
• Global Phase 3 MAPKeeper 301 trial in first-line metastatic pancreatic cancer now recruiting
• Multiple future milestones across Phase 2 lung cancer program and next DCI drug through 2028

Negative

• None.

News Market Reaction – IMRX

-22.10% 4.5x vol

73 alerts

-22.10% Session close to close

-21.6% Trough in 24 hr 4 min

$353.35M Market Cap

4.5x Rel. Volume

In the Jun 1 session, IMRX declined 22.10%, reflecting a significant negative market reaction. Argus tracked a trough of -21.6% from its starting point during tracking. Our momentum scanner triggered 73 alerts that day, indicating high trading interest and price volatility. Trading volume was very high at 4.5x the daily average, suggesting heavy selling pressure.

Data tracked by StockTitan Argus on the day of publication.

Market Context

The stock dropped -22.1% in the session following this news. A negative reaction despite encouraging...

Analysis

The stock dropped -22.1% in the session following this news. A negative reaction despite encouraging data would have contrasted with earlier modestly positive responses to survival updates, such as the prior 3.26% move on May 21, 2026. Investors may at times refocus on funding needs, given a registered $300,000,000 shelf, or on single-arm trial limitations. Such a decline would have fit the occasional divergence seen after events like the AACR ctDNA data release.

Key Figures

Median overall survival: 17.3 months Patients in expanded cohort: 55 patients Standard of care OS: 8.5 months +5 more

8 metrics

Median overall survival 17.3 months Phase 2a atebimetinib + mGnP, 55 first-line metastatic pancreatic cancer patients

Patients in expanded cohort 55 patients First-line metastatic pancreatic cancer Phase 2a trial cohort size

Standard of care OS 8.5 months Median OS for gemcitabine/nab-paclitaxel in pivotal MPACT study

Median progression-free survival 8.3 months Phase 2a atebimetinib + mGnP, data cutoff April 24, 2026

Disease control rate 82% Phase 2a atebimetinib + mGnP, first-line metastatic pancreatic cancer

Overall response rate 36% Confirmed ORR in Phase 2a atebimetinib + mGnP trial

Weight maintenance/gain 84% of participants Maintained or gained weight at three months in Phase 2a trial

Atebimetinib dose 320 mg once daily Dose used with mGnP in first-line metastatic pancreatic cancer trial

Historical Context

5 past events · Latest: May 21 (Positive)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
May 21	Pancreatic survival data	Positive	+3.3%	Reported 17.3‑month median OS in 55 first-line pancreatic cancer patients.
May 15	Q1 results & runway	Positive	+0.4%	Q1 2026 results with cash runway into 2029 and Phase 3 trial update.
Apr 21	ASCO presentation preview	Positive	+4.1%	Announced ASCO oral presentation of updated survival data in 55 patients.
Apr 20	AACR genetic data	Positive	-0.5%	Presented ctDNA data from 123 patients supporting reduced MAPK-driven resistance.
Apr 06	Investor conference	Neutral	-3.1%	Announced CEO participation in Needham virtual healthcare conference.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Clinical and data-focused news has generally seen modest positive alignment, with only one notable divergence after AACR data.

Recent Company History

Over the past two months, Immuneering has steadily built the pancreatic cancer narrative around atebimetinib. On Apr 6, it highlighted an investor conference, followed by AACR genetic data on Apr 20 from 123 patients supporting reduced MAPK-driven resistance. Subsequent ASCO preview and survival updates on Apr 21 and May 21 emphasized the 55‑patient cohort and 17.3‑month median OS, with generally positive price alignment. Today’s ASCO oral presentation largely formalizes and details that previously signaled survival benefit.

Key Terms

median overall survival, progression-free survival, disease control rate, overall response rate, +4 more

8 terms

median overall survival medical

"17.3 months median overall survival in 55 first-line pancreatic cancer patients;"

Median overall survival is the middle point of how long patients live after starting treatment, meaning half live longer and half live shorter. It helps doctors understand how effective a treatment is and gives patients an idea of what to expect about their future.

progression-free survival medical

"Median progression-free survival was 8.3 months (95% CI: 5.9, 9.6), disease control rate"

Progression-free survival is the length of time during and after a treatment that a patient's disease does not get worse, measured from the start of treatment until the disease shows measurable signs of progression or the patient dies. Investors care because longer progression-free survival in clinical trials often signals that a drug is effective, improving chances of regulatory approval, market adoption, and revenue potential—think of it as a stopwatch showing how long a therapy can keep the illness at bay.

disease control rate medical

"Median progression-free survival was 8.3 months (95% CI: 5.9, 9.6), disease control rate (DCR) was 82%"

The disease control rate is the share of patients in a clinical trial whose cancer or condition either shrinks or stops getting worse for a specified period after treatment. Think of it like the percentage of people for whom a treatment hits pause or nudges back the problem rather than letting it progress; higher rates suggest the therapy can meaningfully limit disease, which matters to investors assessing a drug’s potential efficacy and commercial value.

overall response rate medical

"disease control rate (DCR) was 82%, and the confirmed overall response rate (ORR) was 36%."

Overall response rate is the percentage of patients in a clinical study whose measurable disease shrinks or disappears after receiving a treatment. Investors watch it like a product’s “hit rate” because higher response rates can signal a drug’s effectiveness, boost chances of regulatory approval and market demand, and affect a company’s future revenue prospects, similar to how a higher batting average suggests a more reliable player.

Phase 2a medical

"updated clinical data from its ongoing Phase 2a trial evaluating atebimetinib"

Phase 2a is an early stage in testing a new medical treatment or drug, where the main goal is to assess its safety and find the right dosage. For investors, this stage indicates whether the treatment shows initial promise before moving on to larger, more definitive studies; progress here can influence expectations for future development and potential success.

Phase 3 medical

"Global Phase 3 MAPKeeper 301 trial (NCT07562152) in first-line metastatic pancreatic cancer"

Phase 3 is the late-stage clinical testing step for a new drug or medical treatment, where the product is given to large groups of patients to confirm effectiveness, monitor side effects, and compare it to standard care. Successful Phase 3 results are often the final scientific hurdle before regulators decide on approval and market launch—like passing a final exam before graduation—and can sharply change a company's valuation and future revenue prospects.

treatment-related adverse events medical

"Only two categories of Grade 3+ treatment-related adverse events occurring in ≥10% of patients"

Treatment-related adverse events are harmful or unwanted health effects that doctors or regulators determine were caused by a drug, vaccine, device, or other medical therapy. Investors care because how often and how severe these side effects are can shape regulatory approval, labeling, sales potential and legal risk — similar to how product defects can stop or damage a company's ability to sell an item.

metastatic pancreatic ductal adenocarcinoma medical

"metastatic pancreatic ductal adenocarcinoma (mPDAC)"

A late-stage form of pancreatic cancer that starts in the cells lining the pancreatic ducts and has spread to other organs, making it much harder to treat successfully. For investors, the condition matters because it creates urgent demand for effective drugs and diagnostics; trial results, regulatory approvals, or new treatment advances can rapidly change the commercial outlook for companies working in oncology, similar to a sudden shift in demand for a breakthrough product.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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- 17.3 months median overall survival in 55 first-line pancreatic cancer patients; vs. 8.5 months for standard of care chemotherapy in the pivotal MPACT study -

- Only two categories of Grade 3+ treatment-related adverse events occurring in ≥10% of patients, both chemotherapy related -

- 84% of participants maintained or gained weight at three months -

- Global Phase 3 MAPKeeper 301 trial (NCT07562152) in first-line metastatic pancreatic cancer actively recruiting, with first patient dosing expected in mid-2026 -

- Company to hold investor conference call today, at 8:00 a.m. EDT -

NEW YORK, June 01, 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 updated clinical data from its ongoing Phase 2a trial evaluating atebimetinib in combination with modified gemcitabine/nab-paclitaxel (mGnP) in first-line metastatic pancreatic ductal adenocarcinoma (mPDAC).

The data are being presented in an oral session at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting (see Abstract #4013 and accompanying presentation) by Peter Vu, M.D., M.H.A., Associate Professor of Medicine and Medical Director, Cancer Quality, GI Medical Oncology, Experimental Therapeutics & Cellular and Regenerative Medicine at UC San Diego Moores Cancer Center. The presentation showcases data from an expanded cohort totaling 55 first-line pancreatic cancer patients.

“As pancreatic cancer clinicians, we are urgently seeking therapies capable of meaningfully extending survival while preserving patients’ quality of life,” said Daniel Ahn, D.O., Mayo Clinic Arizona, an investigator on the Phase 2a trial of atebimetinib. “The median overall survival of 17.3 months observed in this study is incredibly encouraging relative to historical outcomes in first-line metastatic pancreatic cancer. Equally important, atebimetinib demonstrated a notably favorable tolerability profile, with limited severe treatment-related toxicities and encouraging indicators of preserved functional status, including weight stability – key characteristics for treatments balancing durable clinical benefit and patient experience. Data from this expanded cohort reinforce atebimetinib’s strong potential in first-line pancreatic cancer.”

This open-label, single-arm Phase 2a trial evaluated atebimetinib at 320 mg once daily in combination with mGnP in participants with first-line metastatic pancreatic cancer, irrespective of mutational status. The Company reported the following as of the April 24, 2026 data cutoff date:

• In the expanded 55-patient cohort, median overall survival was 17.3 months (95% CI: 11.2, not reached), compared to 8.5 months median overall survival in the pivotal Phase 3 MPACT study of standard of care gemcitabine/nab-paclitaxel (Von Hoff et al, NEJM, 2013). The median follow-up was 11.6 months.
• Median progression-free survival was 8.3 months (95% CI: 5.9, 9.6), disease control rate (DCR) was 82%, and the confirmed overall response rate (ORR) was 36%.
• In the original 34-patient cohort with longer follow-up (median 17.0 months), median overall survival was also observed to be 17.3 months (95% CI: 11.6, not reached) — supporting the consistency of the survival signal across cohorts with different durations of follow-up.
  

“The data presented at ASCO further strengthen our conviction that atebimetinib has the potential to redefine what it means to live with metastatic pancreatic cancer,” said Ben Zeskind, Ph.D., Co-founder and Chief Executive Officer of Immuneering. “The combination of compelling survival data and a highly favorable safety profile supports the evaluation of this regimen in our Phase 3 study for first-line pancreatic cancer patients, which is now recruiting. We believe the ability of our deep cyclic MEK inhibitors to improve overall survival, while maintaining tolerability, may represent an important advancement for patients and physicians alike.”

Only two categories of Grade 3 or higher treatment-related adverse events occurred in at least 10% of participants, both related to chemotherapy. No Grade 4 adverse events related to atebimetinib and no Grade 5 treatment-related adverse events were reported. Only one participant discontinued atebimetinib while continuing mGnP. The safety profile observed in the trial compared favorably to historical experiences with intensive chemotherapy treatments and combination regimens under development in pancreatic cancer.

Additionally, 84% of participants with available data maintained or gained weight at three months, a potentially important indicator of preserved performance status and tolerability in this patient population where cachexia is common and correlated with poorer outcomes.

Immuneering is currently recruiting patients in MAPKeeper 301 (NCT07562152), a global randomized Phase 3 pivotal trial evaluating atebimetinib plus mGnP versus standard-of-care gemcitabine/nab-paclitaxel in first-line metastatic pancreatic cancer. The trial’s primary endpoint is overall survival.

Upcoming Milestones

• Mid 2026: First patient dosed in Phase 3 MAPKeeper 301 trial.
• 2H 2026: First patient dosed in Phase 2 trial of atebimetinib + anti-PD-1 (cemiplimab) in non-small cell lung cancer.
• Q4 2026: Additional preclinical data supporting atebimetinib + anti-PD-1 in non-small cell lung cancer.
• Mid 2027: Begin IND-enabling studies for next DCI drug program.
• Late 2027: Preliminary Phase 2 data: atebimetinib + anti-PD-1 (cemiplimab) in non-small cell lung cancer.
• Mid 2028: Phase 3 MAPKeeper 301 topline readout expected.

Conference Call

Immuneering will host a conference call and live webcast at 8:00 a.m. EDT / 7:00 a.m. CDT 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 timing of topline results from the study; the timing of dosing of the Phase 2 combination study of atebimetinib in non-small cell lung cancer, including the timing of preliminary results from the study; timing of IND-enabling studies from the next DCI drug program; the ability of phase 2 results presented at ASCO to translate to success and support evaluation in the Company’s phase 3 study; 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
Cdugan@immuneering.com

Media Contact:
Peg Rusconi
Peg.rusconi@deerfieldgroup.com

FAQ

What Phase 2a pancreatic cancer results did Immuneering (Nasdaq: IMRX) present for atebimetinib at ASCO 2026?

Immuneering reported a median overall survival of 17.3 months for atebimetinib plus modified gemcitabine/nab-paclitaxel in 55 first-line metastatic pancreatic cancer patients. According to the company, median progression-free survival was 8.3 months, with 82% disease control and a 36% confirmed overall response rate.

How does atebimetinib plus chemotherapy compare with historical outcomes in metastatic pancreatic cancer for IMRX investors?

The Phase 2a trial showed 17.3-month median overall survival with atebimetinib plus mGnP, compared with 8.5 months reported for gemcitabine/nab-paclitaxel in the pivotal MPACT study. According to Immuneering, this comparison uses historical control data rather than a head-to-head randomized trial.

What safety profile was reported for atebimetinib in Immuneering's Phase 2a pancreatic cancer trial?

According to Immuneering, only two categories of Grade 3 or higher treatment-related adverse events occurred in at least 10% of patients, both chemotherapy related. No Grade 4 adverse events related to atebimetinib and no Grade 5 treatment-related events were reported, and 84% maintained or gained weight at three months.

What are the key details of the Phase 3 MAPKeeper 301 trial for Immuneering (IMRX)?

MAPKeeper 301 is a global randomized Phase 3 trial evaluating atebimetinib plus mGnP versus standard gemcitabine/nab-paclitaxel in first-line metastatic pancreatic cancer. According to Immuneering, the primary endpoint is overall survival, recruitment is ongoing, and first patient dosing is expected in mid-2026 with topline data targeted for mid-2028.

What upcoming clinical milestones has Immuneering outlined for atebimetinib and its pipeline?

Immuneering plans first dosing in Phase 3 MAPKeeper 301 in mid-2026 and a Phase 2 atebimetinib plus anti-PD-1 lung cancer trial in second half 2026. According to the company, additional preclinical lung cancer data are expected Q4 2026, with Phase 3 topline pancreatic cancer readout targeted for mid-2028.

How many patients were included in Immuneering's expanded Phase 2a pancreatic cancer cohort and what was the follow-up?

The expanded cohort included 55 first-line metastatic pancreatic cancer patients, with median follow-up of 11.6 months at the April 24, 2026 cutoff. According to Immuneering, the original 34-patient cohort with 17.0-month median follow-up also showed a 17.3-month median overall survival.