Truist analysts called the results “encouraging” while pointing out certain unknowns in the data. Immuneering plans to kick off a registrational trial for atebimetinib later this year.
Immuneering’s investigational deep cyclic inhibitor atebimetinib nearly doubled the standard survival benchmark in a mid-stage pancreatic cancer study, paving the path toward pivotal development later this year.
Results presented on Wednesday demonstrated an 86% overall survival (OS) rate at 9 months in patients who were given atebimetinib plus chemotherapies gemcitabine/nab-paclitaxel as a first-line therapy. This compared to around 47% OS reported at this time point in patients on standard of care, according to Immuneering. Median OS in the atebimetinib arm was not yet reached at the time of the readout.
At 9 months, patients on the atebimetinib regimen achieved 53% progression-free survival (PFS), compared to 29% for those on standard of care.
Immuneering called these survival findings “compelling,” noting that they “reflect the potential for a durable, compounding benefit” with the atebimetinib combo in the frontline setting. The biotech is working with the FDA on a pivotal study design for atebimetinib, for which it expects feedback in the fourth quarter. Immuneering then expects to launch a registrational study for the asset by the end of the year and to start dosing by mid-2026.
In a note to investors Thursday morning, Truist analysts called the data “encouraging,” though they noted that overall response rates were not updated from a previous readout of the same trial, “so it is not clear how many of the unconfirmed responses previously reported ended up being true confirmed responses.”
In June, Immuneering released 6-month survival data for atebimetinib, touting an OS rate of 94% and PFS rate of 72% in first-line pancreatic cancer. Respective rates for standard of care were 67% and 44%, the biotech noted at the time. Immuneering also reported that overall response rate reached 39% at 6 months, with a disease control rate of 81%.
Shares of Immuneering were up 7.5% at close on Wednesday and up another 8.3% in pre-market trading Thursday. Late Wednesday night, Immuneering also announced a public offering of $175 million worth of shares, as well as a $25 million investment placed by Sanofi.
Taken orally, atebimetinib is a once-daily deep cyclic inhibitor of the MEK protein, which is a key signaling molecule for certain cancer-related pathways. MEK, as per Immuneering’s release on Wednesday, is “pathologically activated” in most cancers, including 97% of pancreatic cancers. Unlike other MEK blockers, which achieve sustained inhibition of the target, atebimetinib works in pulses, resulting in slower but more durable anti-tumor activity.
The company expects to start additional trial combination arms for atebimetinib, including in non-small cell lung cancer.
