Immuneering Presents Molecular Data on Atebimetinib at AACR Meeting

Poster shows Deep Cyclic Inhibitor of MEK may overcome resistance in RAS-mutant tumors

Mar. 17, 2026 at 10:20pm

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Immuneering Corporation announced it will present data at the upcoming AACR Annual Meeting showing that its novel MEK inhibitor atebimetinib may be able to overcome the limitations of conventional MAPK inhibition and provide more durable anti-tumor activity in patients with RAS-mutant solid tumors. The analysis of circulating tumor DNA from over 64 patients found that acquired MAPK pathway alterations were rarely seen in those treated with atebimetinib.

Why it matters

Inhibitors of RAS, RAF, or MEK often only provide temporary benefit due to resistance as tumors acquire new mutations or mechanisms of escape within the MAPK pathway. Atebimetinib, as a Deep Cyclic Inhibitor of MEK, is engineered to mitigate this selective pressure with the goal of achieving more sustained clinical benefit for patients.

The details

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. These findings suggest that Deep Cyclic Inhibitors like atebimetinib have the potential to overcome the limitations of conventional MAPK inhibition.

  • The AACR Annual Meeting will take place April 17-22, 2026 in San Diego, CA.
  • Immuneering 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 players

Immuneering Corporation

A biopharmaceutical company developing novel therapies to improve survival across many cancer indications, including MAPK pathway-driven tumors such as pancreatic cancer.

Atebimetinib

Immuneering's lead product candidate, an oral, once-daily Deep Cyclic Inhibitor of MEK designed to improve survival in cancer patients.

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What’s next

Immuneering 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 takeaway

Atebimetinib, as a novel Deep Cyclic Inhibitor of MEK, has the potential to overcome the limitations of conventional MAPK inhibition and provide more durable anti-tumor activity in patients with RAS-mutant solid tumors, an important advancement in the treatment of difficult-to-treat cancers.