Immuneering Corporation (NASDAQ: IMRX) presented genetic data at the American Association for Cancer Research Annual Meeting showing that patients treated with atebimetinib rarely develop common resistance mechanisms associated with RAS inhibitors.

The analysis examined circulating tumor DNA from 123 patients treated with atebimetinib, including 86 patients receiving monotherapy and 37 patients receiving combination treatment with chemotherapy. The data showed that acquired MAPK pathway alterations were uncommon in atebimetinib-treated patients, contrasting with patterns typically observed with chronic RAS-targeted therapies.

According to the company's findings, emergent resistance following atebimetinib treatment utilized various non-MAPK pathways rather than converging on a single escape mechanism. The analysis also indicated minimal early molecular evolution during treatment.

"Atebimetinib is designed to promote survival by three mechanisms: shrinking tumors durably, preserving body mass by counteracting muscle wasting, and maintaining performance status by maximizing tolerability," said Ben Zeskind, Chief Executive Officer of Immuneering.

Atebimetinib is described as a Deep Cyclic Inhibitor of MEK, engineered to mitigate selective pressure that typically drives resistance mechanisms in conventional MAPK pathway inhibition.

The company expects to begin dosing patients in its Phase 3 MAPKeeper 301 trial of atebimetinib plus modified gemcitabine/nab-paclitaxel in first-line metastatic pancreatic cancer patients in mid-2026. Immuneering also plans to start a Phase 2 trial combining atebimetinib with Libtayo in first-line RAS-mutant non-small cell lung cancer patients in the second half of 2026.

The research was presented at the AACR Annual Meeting taking place April 17-22, 2026 in San Diego. Information in this article is based on the company's press release.