Just two weeks after unveiling full data from its phase 1 program, Amgen’s KRAS inhibitor is back with more. The Big Biotech teased results from a phase 2 study that it says echo the efficacy seen in its closely watched phase 1 trial.
While the earlier study tested four dose levels of the drug, sotorasib, the phase 2 study tested the top dose of the drug in 129 patients with non-small cell lung cancer (NSCLC) whose disease had worsened despite trying a median of two other treatments. Amgen kept specifics under wraps but said Monday afternoon that the new data were “consistent” with the 35% response rate seen in 34 patients who received the top dose in the earlier trial.
At the data cutoff, more than half of the patients were still being treated, and other efficacy measures such as how long patients’ responses lasted looked “promising," Amgen said. The company plans to detail the results at the World Congress on Lung Cancer (WCLC) in January, and it looks forward to discussing them with the FDA and other regulators "to determine the best path forward for sotorasib as a potential treatment for patients with NSCLC harboring the KRAS G12C mutation,” Amgen R&D chief David Reese, M.D., said in a statement.
A phase 3 study pitting sotorasib against chemo drug docetaxel, meanwhile, is already underway.
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Despite the paucity of information on the phase 2 results, industry watchers are optimistic. Jefferies analyst Michael Yee expects an FDA filing soon, he wrote in a note to clients, while Evercore ISI analyst Umer Raffat extrapolated his way to some conclusions and deemed the data “v good.”
Based on when the trial finished enrolling—January of this year—and when submissions closed for WCLC, Raffat inferred the data cutoff to be this past August.
Recruiting "was 'rapid' as per AMGN, and by my math, recruiting was done between" late August of last year and early January 2020, he wrote in an investor note Monday, adding that the “Vast majority of the responses in this first half of pts have kicked in by end-Dec." In other words, there were eight months of follow-up by the time Amgen's abstract submission was due in late August, he figured.
As for patients enrolled later, in November and December of last year, Raffat figured the drug would have started shrinking tumors by January or February, so “even those responders are 7+ months of follow up by today.”
Beyond lung cancer, Amgen is testing sotorasib on its own and in combinations in a variety of KRAS-mutated cancers. Those combinations are the "first next step" to get into other tumor types and treatment settings, Greg Friberg, Amgen’s vice president of global development, oncology said in a previous interview.
There are already studies underway testing sotorasib in combination with treatments such as antibodies and kinase inhibitors that target EGFR, as well as SHP2 inhibitors, MEK inhibitors and PD-1 blockers.