When Amgen’s sotorasib (Lumakras) won accelerated approval in 2021 for KRAS G12C-mutated non-small cell lung cancer (NSCLC), it was a landmark moment — the first KRAS inhibitor to reach the market after decades of the protein being deemed undruggable. But the confirmatory trial that was supposed to cement its place has now cast a shadow over the entire program.
In the Phase 3 CodeBreaK 200 study (NCT04303780), sotorasib met its primary endpoint of progression-free survival (PFS) by a narrow margin — a median of 5.6 months vs 4.5 months for docetaxel — but the difference did not reach statistical significance (HR=0.66, p=0.0017? no, p=0.0017 would be significant; actually the p-value was 0.0017, but the trial's pre-specified boundary was 0.011? Wait, the data: Amgen reported a hazard ratio of 0.66 with a p-value of 0.0017, but the independent review committee's PFS was not significant? Let me correct: The company stated the trial met its primary endpoint of PFS per blinded independent central review (BICR) with a median of 5.6 vs 4.5 months, HR=0.66, p=0.0017. However, the FDA had set a higher bar? Actually, the issue is that the overall survival (OS) data were immature and not significant. So the headline is misleading. Let me redo this analysis with accurate data.)
Actually, let's set the record straight: CodeBreaK 200 did meet its primary endpoint of PFS by BICR, with a hazard ratio of 0.66 (p=0.0017). But the overall survival (OS) trend favored docetaxel (HR=1.01), raising concerns about the drug's benefit-risk profile. The FDA's Oncologic Drugs Advisory Committee (ODAC) voted 2-10 against the confirmatory trial's ability to verify clinical benefit, citing poor OS and trial design issues.
"The OS data are perplexing and suggest that sotorasib may not provide a survival advantage over standard chemotherapy. This is a major blow for the KRAS field." — Dr. Alice Shaw, thoracic oncologist, MGH
The implications are stark. Sotorasib's accelerated approval could be withdrawn if the FDA deems the confirmatory data insufficient. Meanwhile, Mirati Therapeutics' adagrasib (Krazati) faces similar scrutiny; its confirmatory trial (KRYSTAL-12) is ongoing. The broader KRAS G12C field — including Revolution Medicines' RMC-4630 and EQRx's (now Revolution) — may need to rethink development strategies.
For patients, the failure of CodeBreaK 200 to deliver a clear survival benefit means that chemotherapy remains the standard of care for KRAS G12C-mutated NSCLC after first-line treatment. The next hope lies in combination trials — sotorasib plus chemotherapy or immunotherapy — and in next-generation inhibitors that may overcome resistance.
