PARIS – For patients with non–small cell lung cancers (NSCLC) bearing the KRAS G12C mutation that have progressed on prior therapies, the first-in-class KRAS G12C inhibitor sotorasib (Lumykras) was associated with better progression-free survival (PFS) and objective response rates than docetaxel in the randomized, phase 3 CodeBreaK 200 trial.
Among 345 patients who had experienced disease progression after prior platinum-based chemotherapy and an immune checkpoint inhibitor, 1-year PFS rates at a median follow-up of 17.7 months were 24.8% for patients randomized to receive sotorasib versus 10.1% for patients assigned to docetaxel, reported Melissa L, Johnson, MD, from the Sarah Cannon Research Institute at Tennessee Oncology in Nashville.
“In my opinion, this supports sotorasib as a new second-line standard for patients with KRAS G12C non–small cell lung cancer,” she said in a media briefing prior to her presentation of the data in an oral abstract session at the annual meeting of the European Society for Medical Oncology.
First phase 3, randomized, controlled trial
The trial is the first head-to-head, randomized comparison pitting a KRAS G12C inhibitor against the standard of care in patients with NSCLC.
Approximately 30% of patients with NSCLC have KRAS driver mutations, and KRAS G12C–mutant NSCLC comprises an estimated 13% of all NSCLC cases, Dr. Johnson said.
Sotorasib was hailed as “a triumph of drug discovery” when early results of the trial were reported at the 2020 ESMO annual meeting. It is a small-molecule, specific, and irreversible inhibitor of KRAS that interacts with a “pocket” on the gene’s surface that is present only in an inactive conformation of KRAS. The drug inhibits oncogenic signaling and tumorigenesis by preventing cycling of the oncogene into its active form.
CodeBreaK 200 details
A total of 345 patients from sites in the United States, Europe, Asia and Australia were enrolled and randomly assigned to receive either oral sotorasib 960 mg daily, or intravenous docetaxel 75 mg/m2 every 3 weeks.
As noted before, the trial met its primary endpoint of a statistically significant improvement in PFS with sotorasib as measured by independent central reviewers blinded to study assignment, with a hazard ratio of 0.66 (P = .002). Median PFS with sotorasib was 5.6 months, compared with 4.5 months for docetaxel.
The objective response rate was significantly improved for sotorasib versus docetaxel (28.1% vs. 13.2%, P < .001), as was the disease control rate at 82.5% for sotorasib versus 60.3% for docetaxel. Overall survival was not significantly different between treatment arms, though the study was not powered for this endpoint.
Sotorasib was also superior to docetaxel at forestalling deterioration of patients’ global health status, physical functioning, and cancer-related symptoms such as dyspnea and cough. There was no significant difference between the study arms in reported chest pain, however.
Grade 3 or greater treatment-related adverse events occurred in 33.1% of patients with sotorasib, compared with 40.4% of patients on docetaxel.
‘Tremendous advance’
“I think the conduct of this study is impressive, it’s well designed, it was well run, any imbalances really favored the control arm, and I think that this advance is relevant not just for performance status 0 and 1 KRAS G12C–mutant patients, but even beyond, to performance status 2 and perhaps even performance status 3,” commented Natasha Leighl, MD, MMSc, from the Princess Margaret Cancer Center, Toronto, the invited discussant.
Comparing the drug performance of the respective arms, Dr. Leighl said that “I don’t think I’ve ever seen such good outcomes in a randomized trial with the chemotherapy, but unfortunately sotorasib performed a little bit less well than we had hoped.”
Nonetheless, “I think CodeBreaK 200 is a tremendous advance for patients. It is a confirmatory positive trial, and I think sotorasib is the new standard of care in patients who have received chemo and immunotherapy for KRAS G12C–mutant lung cancer,” she said.
CodeBreaK 200 was supported by Amgen. Dr. Johnson disclosed a consulting and advisory role with payments to her institution from Amgen and others. Dr. Leighl disclosed institutional grant funding and personal honoraria from Amgen and others.