Why Immuneering Stock Soared Over 40% After-Hours Today

Shares of Immuneering Corp. rose 42% in after-hours trading on Wednesday after the company’s Phase 2a trial of atebimetinib in combination with modified gemcitabine/nab-paclitaxel showed an 86% overall survival rate in patients with first-line pancreatic cancer at nine months, compared with a 47% benchmark for standard of care.

The stock closed Wednesday’s regular session up 7.5% at $9.23.

Immuneering said it plans to seek regulatory feedback on its pivotal trial plans in the fourth quarter and, subject to that feedback, aims to launch a Phase 3 trial of atebimetinib plus mGnP by the end of 2025, with patient dosing to begin by mid-2026. 

The company also expects to initiate additional atebimetinib clinical trial combination arms in 2026, including in non-small cell lung cancer.

Progression-free survival at nine months was 53%, compared to a 29% benchmark for standard of care. At six months, overall survival was 94%, and progression-free survival was 70%, both rates exceeding historical benchmarks. Median overall survival has not yet been reached.

The treatment was generally well-tolerated. The serious side effects, observed in more than 1 in 10 people, included low white blood cell counts, which can increase the risk of infection, and anemia, characterized by low red blood cell levels. No new safety concerns were identified.

CEO Ben Zeskind said the nine-month overall survival data widened the gap against the standard of care, describing the results as “extraordinary.” Chief Scientific Officer Brett Hall said atebimetinib, designed as a Deep Cyclic Inhibitor, represents a “fundamental shift in targeted therapy.” 

Vincent Chung, principal investigator of the trial at City of Hope, said the results mark “an important step” toward urgently needed new treatment options for pancreatic cancer, adding that the company is also planning a confirmatory study. 

Separately, Immuneering announced a proposed underwritten public offering of its Class A common stock, or in lieu of stock, pre-funded warrants. The company also stated that Sanofi agreed to purchase $25 million of shares in a concurrent private placement at the public offering price, with both transactions expected to close simultaneously. 

Immuneering plans to use the proceeds to advance the development of its drug candidates and for general corporate purposes.

On Stocktwits, retail sentiment for Immuneering was ‘extremely bullish’ amid a 3,540% surge in 24-hour message volume, placing it among the top 10 trending equities on the platform. 

One user said the offering “didn’t completely kill the momentum,” adding that it gave them hope for the next trading day. 

Another user said they were in “for the long haul, which now extends into mid-2026,” and added that the stock offering would likely be shrugged off within a day before analysts begin calculating Immuneering’s valuation based on potential sales of what they described as the gold standard for treating pancreatic cancer.

Immuneering’s stock has surged 320% so far in 2025.

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