Immuneering (IMRX) investor relations material

Current clinical progress and pipeline

• Phase III trial of third-generation MEK inhibitor atebimetinib is underway in first-line pancreatic cancer, with over 40 sites active and top-line readout expected mid-2028.

• Multiple ongoing studies include a phase II lung cancer trial in combination with cemiplimab, with first patient dosing expected by year-end and top-line results by end of next year.

• Phase II data in first-line pancreatic cancer showed 84% of patients were weight stable or gained weight at three months, a significant outcome in this population.

• Additional phase II arms are ongoing, including combinations with FOLFIRINOX, with further data to be shared in the future.

Differentiation and mechanism of atebimetinib

• Atebimetinib is a third-generation MEK inhibitor designed to address toxicity issues seen in earlier generations, using a novel Deep Cyclic Inhibition approach.

• Demonstrates improved tolerability, with significantly reduced rates of rash and diarrhea compared to previous MEK inhibitors.

• Mechanistically, it blocks the CRAF bypass, enabling efficacy in RAS mutant disease, and is distinct from first- and second-generation MEK inhibitors.

• Preclinical data suggest strong synergy when combined with mutation-specific RAS inhibitors.

Key clinical data and patient outcomes

• Phase II study in first-line pancreatic cancer showed a median overall survival (OS) of 17.3 months, a result not achieved by any RAS inhibitor in this setting.

• Only two Grade 3 treatment-related adverse events (anemia and neutropenia) occurred in more than 10% of patients, both linked to chemotherapy, indicating high tolerability.

• 60% of patients were able to proceed to second-line treatment, compared to 40% in the standard of care MPACT study.

• 84% of patients were weight stable or gained weight, supporting better quality of life and survival.