Weeks after dropping big response data, Amgen lines up priority review for KRAS hopeful sotorasib in NSCLC

Amgen is looking to go where no other drugmaker has gone before with the KRAS inhibitor sotorasib, which posted big Phase II lung cancer response data in late January. The FDA has been listening, and now it’s ready to give Amgen its ear.

The FDA will speedily review sotorasib’s application to treat second-line patients with locally advanced or metastatic non-small cell lung cancer in what would be the first successful bid to inhibit KRAS, Amgen said in a release.

The agency set a review date of Aug. 16.

Sotorasib’s pick up for priority review comes just weeks after Amgen released ORR data from its Phase III CODEBREAK100 study showing the molecule posted a 37.1% overall response rate among 126 patients with advanced, KRAS G12C-mutated NSCLC. There were three complete responses and 43 partials, with a median duration of response of 10 months. Progression-free survival hit 6.8 months.

Those data, which backed up findings from a much-smaller Phase I study, looked at the time like a textbook case for approval, and now the FDA appears set to give sotorasib its shot. SVB Leerink analyst Geoffrey Porges said at the time of the data drop that he expected a quick approval and $1 billion in peak sales in the indication.

A first in KRAS would come as a big market advantage with one major competitor — Mirati Therapeutics — still in the clinic for their own candidate. Meanwhile, Amgen has had significantly less success in taking sotorasib into other solid tumor types and has focused much of its R&D brain trust chasing combination therapies for the drug to expand its range into earlier settings.

In a Phase I trial in colorectal, sotorasib posted just a 7.1% response rate, with the majority of the 42 patients in the trial having received at least three prior lines of therapy — a testament to how hard the mutation is to dose.

In other tumors outside of NSCLC and colorectal, the drug fared even worse, with just three of 22 patients showing partial responses seven weeks after treatment.

Sotorasib secured the priority review after the FDA granted it a breakthrough designation in NSCLC. The molecule is under audit as part of the FDA’s real-time oncology review program, which could speed approval before the Aug. 16 target date.