FDA panel says Amgen’s Phase III lung cancer KRAS drug data is unreliable

A US Food and Drug Administration (FDA’s) Oncology Advisory Committee (AdCom) has raised questions about the upcoming decision to grant traditional approval of Amgen’s high-profile KRAS G12C inhibitor Lumakras (sotorasib).

Lumakras was granted accelerated approval in May 2021 for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) with KRAS G12C mutations, who had received at least one prior systemic therapy. This approval was based on the CodeBreaK 200 trial (NCT04303780) of sotorasib versus docetaxel.

Lumakras generated $285m in sales last year worldwide, according to Amgen’s 2022 annual report to shareholders.

The latest AdCom questioned the reliability of the data In the briefing document released by the FDA from the meeting, several features of the Codebreak trial were listed that were inconsistent with a sufficient well-controlled trial. The main issue noted was that too many patients were allowed to swap between the treatment and control arms of the study. When asked if the progression-free survival (PFS) could be reliably interpreted in Amgen’s study, the panellists voted 10 to 2 that the primary endpoint could not be relied upon.

The FDA does not have any plans to withdraw the drug at the moment, however, the agency may request an additional confirmatory trial from Amgen on Lumakras. A decision on traditional approval is expected to be made in December 2023.  

Lumakras targets the G12C mutation in the KRAS gene—a target that was once deemed ‘undruggable’ by scientists. According to GlobalData, KRAS G12C inhibitors in NSCLC are forecast to achieve over $1bn in sales by 2024.

GlobalData is the parent company of Pharmaceutical Technology.