Immuneering (IMRX) investor relations material

Platform and mechanism

• Deep Cyclic Inhibition is designed to break the breadth/tolerability trade-off, enabling broad treatment across MAPK-driven cancers with improved tolerability.

• Atebimetinib is described as a third-generation MEK inhibitor for BRAF- and RAS-mutant populations; rash rates were reduced to one-third of original levels.

• MEK inhibitors generated over $3 billion in sales in 2025 across RAF-inhibitor combinations and monotherapy, validating the target commercially.

Phase II pancreatic cancer data

• In 55 first-line pancreatic cancer patients treated with atebimetinib plus chemotherapy, median OS was 17.3 months, among the highest phase II results cited for this setting.

• Only two categories of grade 3 treatment-related adverse events affected more than 10% of patients; both were associated with chemotherapy, with none attributed to atebimetinib.

• 84% of evaluable patients were weight stable or gaining weight at 3 months; an AACR comparison found roughly twice the benchmark proportion in pancreatic cancer.

• The phase II enrolled without genetic testing, including patients across KRAS variants and those with unknown RAS status.

• Weight-stable or weight-gaining patients had longer survival; median OS in that subgroup was not reached at the late-April data cutoff.

Clinical development and strategy

• MAPKeeper-301 is a randomized phase III first-line pancreatic cancer trial of atebimetinib plus gemcitabine and nab-paclitaxel every other week versus standard chemotherapy; OS is the primary endpoint.

• Phase III enrollment was ahead of schedule, with 76 sites listed and European sites starting; top-line data are guided for mid-2028, with potential to accelerate.

• A longer-follow-up phase II update is guided for H1 2027; median follow-up at the ASCO data cutoff was 11.6 months across 55 patients.

• A potential treatment sequence is atebimetinib plus Gem/Nab first line followed by a pan-RAS inhibitor second line; reported acquired alterations rarely involved RAS or the MAP kinase pathway.