Immuneering Advances Atebimetinib Development With Phase 3 Initiation Planned For Mid-2026

Immuneering Corp. (IMRX), a clinical-stage oncology company, has disclosed that it remains well-positioned to initiate dosing of the first patient in its forthcoming Phase 3 trial of Atebimetinib for first-line metastatic pancreatic cancer in the mid-2026 timeframe. The global Phase 3 registrational study, designated MAPKeeper 301, will assess Atebimetinib (320 mg daily dosing) administered alongside modified gemcitabine and nab-paclitaxel (mGnP) against gemcitabine and nab-paclitaxel (GnP) as a control arm.

The trial design calls for approximately 510 patient enrollments across participating sites. The company successfully completed its End-of-Phase 2 meeting with the FDA and secured regulatory guidance from the European Medicines Agency, with both authorities supporting the trial’s architecture, including the selection of overall survival as the primary efficacy measure. Secondary endpoints encompass progression-free survival, overall response rate, disease control rate, and patient quality of life assessments.

Immuneering intends to disclose overall survival findings from the Phase 2a study evaluating Atebimetinib combined with Gemcitabine in treatment-naïve pancreatic cancer patients in the near term. The initiation of this Phase 3 program represents a significant milestone for the company’s oncology pipeline and underscores the therapeutic potential of this combination approach in an indication with substantial unmet clinical needs.

In recent market activity, Immuneering disclosed that it has been selected for inclusion in the Nasdaq Biotechnology Index, effective December 22, 2025. IMRX shares closed at $5.50, reflecting a 4.18% decline during Wednesday’s session.