Osimertinib superior to gefitinib, erlotinib in first-line treatment of advanced NSCLC
The third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) osimertinib affords better progression-free survival (PFS) than standard EFGR-TKIs in the first-line treatment of EGFR mutation–positive advanced nonsmall-cell lung cancer (NSCLC), with similar safety profile and lower serious adverse event rates, as reported in the phase III FLAURA trial.
Results of the analysis involving 556 patients with previously untreated, EGFR mutation–positive (exon 19 deletion or L858R) advanced or metastatic NSCLC revealed that median PFS (as assessed by investigators) was significantly longer in the group treated with osimertinib (80 mg once daily; n=279) than in the group given a standard EGFR-TKI (gefitinib at 250 mg or erlotinib at 150 mg once daily; n=277; 18.9 vs 10.2 months). [New Engl J Med 2017;doi:10.1056/NEJMoa1713137]
Specifically, osimertinib reduced the risk of disease progression or death by more than 50 percent (hazard ratio, 0.46; 95 percent CI, 0.37–0.57; p<0.001).
No marked difference in the objective response rate was seen between the two treatment groups: 80 percent with osimertinib vs 76 percent with standard EGFR-TKIs (odds ratio, 1.27; 0.85–1.90; p=0.24). However, duration of response was longer with osimertinib (median, 17.2 months; 13.8–22.0 vs 8.5 months; 7.3–9.8).
Interim analysis data (25 percent maturity) were still immature for evaluation of overall survival. At 18 months, the survival rate was 83 percent with osimertinib and 71 percent with standard EGFR-TKIs (hazard ratio for death, 0.63; 0.45 to 0.88; p=0.007 [nonsignificant in the interim analysis]).
Serious adverse events, such as prolongation of the QT interval and interstitial lung disease, were reported in 22 percent of patients in the osimertinib group and 25 percent in the standard EGFR-TKI group.
“Although there was no statistical comparison of safety data, the safety profile of osimertinib was similar to that of standard EGFR-TKIs, but with somewhat lower rates of adverse events of grade 3 or higher [34 vs 45 percent], despite a longer median duration of exposure with osimertinib,” the investigators said.
The most common adverse events due to any cause (treatment-related or not) were rash or acne, diarrhoea, and dry skin.
Findings of the FLAURA trial “suggest that osimertinib is superior to current standard EGFR-TKIs as first-line therapy,” the investigators said, adding that the trial population had demographic and clinical characteristics that were in line with those of the global population of patients with EGFR mutation–positive advanced NSCLC.
Nevertheless, the trial was not without limitations. Among the investigators pointed out were the exclusion of afatinib from the comparator group and that magnetic resonance imaging of the head was not mandated for all the patients, limiting the ability to detect asymptomatic brain metastases.