Immuneering (NASDAQ:IMRX) reported updated positive data for atebimetinib in first-line pancreatic cancer patients during a conference call tied to its ASCO presentation, highlighting survival, tolerability and planned development milestones for the company’s lead program.
Ben Zeskind, Immuneering’s co-founder and chief executive officer, said the company’s phase II-A study of atebimetinib at 320 mg once daily in combination with modified gemcitabine nab-paclitaxel chemotherapy showed a median overall survival of 17.3 months in an original cohort of 34 first-line pancreatic cancer patients. He noted that the study was open-label and non-randomized, and said the results should be interpreted in the context of established benchmarks.
Updated Cohort Maintains Median Overall Survival
Zeskind said Immuneering initially planned to enroll 30 patients and enrolled 34 in the original cohort. Due to demand from study sites, the company added 21 more patients, expanding the cohort to 55. In the expanded cohort, median overall survival remained 17.3 months, according to Zeskind.
He said the survival curves for the 34-patient and 55-patient cohorts were “very similar,” and that the consistency of the median overall survival and the overall shape of the survival curves supported the strength of the data.
Immuneering compared its results with historical benchmarks from pivotal studies of standard-of-care regimens in first-line pancreatic cancer, including gemcitabine nab-paclitaxel from the MPACT study, FOLFIRINOX from the PRODIGE study and NALIRIFOX from the NAPOLI-3 study. Zeskind said the company’s 17.3-month median overall survival was above benchmarks that he said were around 11.1 months for the latter two regimens and 8.5 months for gemcitabine nab-paclitaxel in MPACT.
Tolerability and Weight Stability Highlighted
The company said atebimetinib plus modified gemcitabine nab-paclitaxel showed a favorable tolerability profile. Zeskind said only two categories of treatment-related adverse events occurred at Grade 3 or higher levels in more than 10% of patients, and both were chemotherapy-related.
Immuneering also reported that 84% of the 55 patients with baseline and three-month weight data were weight stable or gained weight. Zeskind said the number had remained steady since earlier reporting and suggested that preservation of body mass may contribute to survival, while noting that the effect cannot be definitively separated from other factors.
In response to an analyst question from Jay Olson of Oppenheimer, Zeskind said the company believes weight stability, tolerability and tumor reductions may have contributed to 60% of patients being able to receive second-line therapy, compared with 40% in the MPACT benchmark study. He said phase III data would be needed to better assess those factors.
Additional Efficacy Measures
Beyond overall survival, Immuneering reported a median progression-free survival of 8.3 months, compared with 5.5 months for the MPACT standard-of-care benchmark. The company also reported a confirmed overall response rate of 36%, compared with 23% for the benchmark, and a disease control rate of 82%, compared with 48%.
Zeskind said overall survival remains the most important endpoint for patients and regulators and is the sole primary endpoint in the phase III MAPKeeper 301 trial. He said other endpoints help support the survival observations.
The company also presented waterfall and spider plot data showing tumor regression among evaluable patients. Zeskind said confirmed responses were observed across patients with a range of RAS mutations as well as those without known RAS mutations. He said this supported the company’s decision not to require genetic testing for enrollment in either the phase II study or the phase III trial.
Phase III Trial and Pipeline Plans
MAPKeeper 301 is a global phase III study evaluating atebimetinib plus modified gemcitabine nab-paclitaxel against a standard-of-care gemcitabine nab-paclitaxel control arm in first-line metastatic pancreatic cancer. Zeskind said the company plans to dose the first patient in mid-2026 and expects a top-line readout in 2028.
The company also outlined several additional development milestones:
- First patient dosing in a phase II lung cancer trial of atebimetinib in combination with anti-PD-1 therapy is planned for the second half of 2026.
- Preclinical data on atebimetinib plus anti-PD-1 in a lung cancer model are planned for the fourth quarter of 2026.
- IND-enabling studies for Immuneering’s next Deep Cyclic Inhibitor program are expected to begin in 2027.
- Phase II data from the lung cancer combination study are expected in late 2027.
Zeskind said Immuneering ended the first quarter with approximately $199 million in cash, which the company expects to fund operations into 2029. He also said patent protection for atebimetinib is expected into late 2045.
During the question-and-answer session, analysts asked about competitive developments in pancreatic cancer, including enthusiasm around second-line treatments. Zeskind said first-line and second-line pancreatic cancer are different settings and described potential future treatment options as complementary rather than mutually exclusive.
“It’s really not an either/or, it’s a both/and,” Zeskind said, adding that Immuneering believes atebimetinib’s tolerability profile and lack of required genetic testing are differentiating features in the first-line setting.
About Immuneering (NASDAQ:IMRX)
Immuneering (Nasdaq: IMRX) is a clinical-stage biopharmaceutical company leveraging artificial intelligence and its proprietary RABIT (Repurposing and Accelerating Biotechnology Tools) platform to design and optimize small-molecule and peptide therapies. By analyzing large-scale biomedical datasets, Immuneering’s machine learning algorithms identify novel drug–target interactions, repurpose existing drug scaffolds and accelerate lead candidate selection. The company’s AI-driven approach aims to reduce development timelines and improve therapeutic profiles in areas of high unmet medical need.
The company’s lead program, IRX-2, is a small-molecule candidate currently in Phase 2 clinical trials for the treatment of painful diabetic peripheral neuropathy.
