Immuneering’s Atebimetinib Shows 17.3-Month OS in Pancreatic Cancer Phase II Trial

Immuneering Corporation’s third-generation MEK inhibitor, atebimetinib, demonstrated a median overall survival of 17.3 months in a Phase II trial for first-line pancreatic cancer, a milestone not achieved by any prior RAS inhibitor, CEO Ben Dormond stated at the H.C. Wainwright 28th Annual Global Investment Conference on September 14, 2026. The data, presented at ASCO 2024, included 55 patients treated with atebimetinib combined with gemcitabine nab-paclitaxel every other week, with 84% of evaluable patients maintaining or gaining weight by month three—a notable improvement over historical standards. Additionally, 60% of patients progressed to second-line therapy, compared to 40% in the MPACT pivotal study of standard gemcitabine alone. The company’s Phase III MAPKeeper 301 trial, enrolling over 40 clinical sites, began dosing patients in June 2024 and aims for top-line results by mid-2028. Meanwhile, a Phase IIa program includes a FOLFIRINOX arm, featuring a single case report of a complete response, while a Phase II lung cancer study combines atebimetinib with Regeneron’s cemiplimab under a supply agreement. Safety profiles showed reduced rash incidence (less than one-third of patients) and a 50% decrease in diarrhea versus continuous MEK inhibition, with only anemia and neutropenia—both chemotherapy-related—reaching Grade 3 severity in over 10% of patients. Dormond emphasized that atebimetinib’s tolerability resolves historical toxicity challenges of MEK inhibitors, positioning the drug as a transformative option for pancreatic cancer treatment. The company’s balance sheet remains strong, with a current ratio of 19.47 but accelerating cash burn, supported by upcoming Phase III readouts and partnerships.