Item 8.01 Other Events.
On June 17, 2025, Immuneering Corporation (the "Company", "we", "us" and "our") announced interim data from its ongoing Phase 2a clinical trial arm evaluating atebimetinib (formerly known as IMM-1-104), a once-daily oral mitogen-activated protein kinase kinase ("MEK") inhibitor, in combination with modified Gemcitabine/nab-Paclitaxel ("mGnP") in first-line pancreatic cancer patients (the "mGnP Arm"), which is part of Company's ongoing Phase 1/2a clinical trial of atebimetinib in patients with advanced RAS- and/or RAF-mutant solid tumors.
The Company announced that, as of a cutoff date of May 26, 2025 (the "Cutoff Date"), of the 36 response evaluable patients in the mGnP Arm dosed at the 240 mg or 320 mg once-daily dose level of atebimetinib in combination with mGnP, one patient achieved a complete response, 13 patients achieved a partial response (with four such patients pending response confirmation at a subsequent scan), 15 patients achieved stable disease, and seven patients showed progressive disease, collectively representing an interim 81% (29/36) disease control rate ("DCR") and an interim 39% (14/36) overall response rate ("ORR"), in each case as measured by the Response Evaluation Criteria in Solid Tumors ("RECIST") method.
The Company also announced that, as of the Cutoff Date, 94% overall survival ("OS") and 72% progression free survival ("PFS") were observed in the intent-to-treat population of 34 patients dosed at the 320 mg once-daily dose level of atebimetinib in combination with mGnP (the "320 mg ITT Population"), in each case with a median follow-up time of six months. As of the Cutoff Date, neither the median OS nor the median PFS of the 320 mg ITT Population had been reached.
The Company also announced that, as of the Cutoff Date, atebimetinib in combination with mGnP was observed to be generally well tolerated. As of the Cutoff Date, Grade ≥ 3 treatment-emergent adverse events ("TEAEs") observed in 10% or greater of patients in the 320 mg ITT Population were limited to Anemia (six patients or 18%) and Neutropenia (five patients or 15%). No Grade 5 TEAEs were observed in this subset of the patient population.
Also on June 17, 2025, the Company announced that additional data from the Phase 2a portion of the Company's atebimetinib Phase 1/2a trial was expected in the fourth quarter of 2025, and that the Company planned, pending regulatory feedback expected in the fourth quarter of 2025, to initiate a pivotal trial evaluating atebimetinib in combination with mGnP in first-line pancreatic cancer patients in 2026, and to initiate additional clinical trial combination arms evaluating atebimetinib also in 2026.