Immuneering Corporation (Nasdaq: IMRX) announced the publication of preclinical findings on its drug candidate atebimetinib in Cancer Research, a peer-reviewed journal of the American Association for Cancer Research.

The study, titled "Dual-MEK Inhibitor Atebimetinib Displays Broad Activity in RAS- and RAF-Mutant Tumors via Deep Cyclic Inhibition and Resisting RAF-Bypass," reports that atebimetinib showed antitumor activity across KRAS-, NRAS-, and BRAF-mutant tumor models, including colorectal, lung, and melanoma.

According to the publication, atebimetinib reduced both pERK and pMEK in tested models, whereas other MEK inhibitors reduced pERK while allowing pMEK to accumulate — a molecular pattern associated with RAF-mediated pathway reactivation. The compound's short half-life was said to produce deep but transient suppression of MAPK signaling followed by recovery periods between doses.

In head-to-head preclinical studies, atebimetinib produced greater tumor growth inhibition compared to binimetinib, an FDA-approved MEK inhibitor, across KRAS-, NRAS-, and BRAF-mutant models.

In a cancer cachexia model using syngeneic Colon-26 cells, animals treated with atebimetinib maintained body weight within approximately 5% of baseline through roughly two weeks of dosing. Untreated control animals lost a median of more than 20% of body weight by approximately day 14.

Immuneering is currently enrolling patients in MAPKeeper 301 (NCT07562152), a Phase 3 trial evaluating atebimetinib combined with modified gemcitabine/nab-paclitaxel in first-line metastatic pancreatic cancer. The company also expects to dose the first patient in a Phase 2 trial combining atebimetinib with cemiplimab in first-line RAS-mutant non-small cell lung cancer in the second half of the year.