Immuneering has reported updated data on atebimetinib in first-line pancreatic cancer patients, linking the MEK inhibitor to 64% overall survival (OS) at 12 months.
The update is the latest cut of data from a phase 2a trial that is testing atebimetinib with a modified form of a chemotherapy combination currently used in pancreatic cancer. After six months, 94% of patients were alive, while the OS rate slipped to 86% by Month 9.
Immuneering compared both figures favorably to data from a 2013 study of the full dose and schedule of the chemotherapy combination.
After viewing the 12-month data, the biotech again hailed the difference between OS on atebimetinib and in the historical external chemotherapy trial. OS on the chemotherapy regimen after 12 months was 35% in the historical comparison, compared to 64% in the atebimetinib trial.
Immuneering’s study is yet to reach its median OS. The chemotherapy regimen had a median OS of 8.5 months in the historical trial. Median progression-free survival (PFS) was 8.5 months on atebimetinib. Immuneering compared the result to the external PFS benchmark for chemotherapy of 5.5 months.
On a call with investors to discuss the data, Immuneering CEO Benjamin Zeskind, Ph.D., fielded questions on the extent to which PFS predicts OS as analysts sought to understand how survival data may mature.
“Progression-free survival is a surrogate endpoint. It’s something that is helpful to assess the robustness of the overall survival result that you’re seeing,” Zeskind said.
“That full three-month separation in terms of median PFS, we think just adds further robustness to the strong overall survival results that we're seeing,” the CEO continued. “We're thrilled to see that kind of separation on progression-free survival.”
Immuneering’s share price yo-yoed on either side of the readout. The stock rose 24% Wednesday in the run-up to the after-hours update, only to give up most of the gains after the data dropped. Immuneering was trading at $6.42 before the market opened Thursday, down 23% on its closing price Wednesday.
Data from an expanded cohort of 50 patients are due in the first half of 2026. While the update could shed some light on atebimetinib’s prospects, the true test will start when Immuneering doses the first patient in a pivotal trial around the midpoint of 2026. Zeskind said the trial will compare atebimetinib plus chemotherapy to the standard-of-care regimen in about 510 patients, with OS being the primary endpoint.
Zeskind expects to report top-line results in mid-2028. By then, Immuneering may have a clearer picture of the competitive landscape. Revolution Medicines has picked second-line pancreatic cancer as the lead indication for daraxonrasib, with data due in that setting this year, but is moving into the first-line space targeted by Immuneering. In November, Revolution said it aimed to start a first-line phase 3 trial in 2025.
Revolution committed to the phase 3 study after reporting an overall response rate of 55% in patients with first-line metastatic RAS-mutant pancreatic cancer who received daraxonrasib plus chemotherapy. Immuneering has identified safety and tolerability as an area where atebimetinib may have an edge over daraxonrasib. The biotech reported no new safety signals in the 12-month update.