Meng‐Chih Lin

BACKGROUND: Osimertinib is a third-generation, irreversible tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR-TKI) that selectively inhibits both EGFR-TKI-sensitizing and EGFR T790M resistance mutations. A phase 3 trial compared first-line osimertinib with other EGFR-TKIs in patients with EGFR mutation-positive advanced non-small-cell lung cancer (NSCLC). The trial showed longer progression-free survival with osimertinib than with the comparator EGFR-TKIs (hazard ratio for disease progression or death, 0.46). Data from the final analysis of overall survival have not been reported. METHODS: In this trial, we randomly assigned 556 patients with previously untreated advanced NSCLC with an EGFR mutation (exon 19 deletion or L858R allele) in a 1:1 ratio to receive either osimertinib (80 mg once daily) or one of two other EGFR-TKIs (gefitinib at a dose of 250 mg once daily or erlotinib at a dose of 150 mg once daily, with patients receiving these drugs combined in a single comparator group). Overall survival was a secondary end point. RESULTS: The median overall survival was 38.6 months (95% confidence interval [CI], 34.5 to 41.8) in the osimertinib group and 31.8 months (95% CI, 26.6 to 36.0) in the comparator group (hazard ratio for death, 0.80; 95.05% CI, 0.64 to 1.00; P = 0.046). At 3 years, 79 of 279 patients (28%) in the osimertinib group and 26 of 277 (9%) in the comparator group were continuing to receive a trial regimen; the median exposure was 20.7 months and 11.5 months, respectively. Adverse events of grade 3 or higher were reported in 42% of the patients in the osimertinib group and in 47% of those in the comparator group. CONCLUSIONS: Among patients with previously untreated advanced NSCLC with an EGFR mutation, those who received osimertinib had longer overall survival than those who received a comparator EGFR-TKI. The safety profile for osimertinib was similar to that of the comparator EGFR-TKIs, despite a longer duration of exposure in the osimertinib group. (Funded by AstraZeneca; FLAURA ClinicalTrials.gov number, NCT02296125.).

Osimertinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), potently and selectively inhibits EGFR-TKI-sensitizing and EGFR T790M resistance mutations. In the Phase III FLAURA study (NCT02296125), first-line osimertinib improved outcomes vs comparator EGFR-TKIs in EGFRm advanced non-small cell lung cancer. This analysis identifies acquired resistance mechanisms to first-line osimertinib. Next-generation sequencing assesses circulating-tumor DNA from paired plasma samples (baseline and disease progression/treatment discontinuation) in patients with baseline EGFRm. No EGFR T790M-mediated acquired resistance are observed; most frequent resistance mechanisms are MET amplification (n = 17; 16%) and EGFR C797S mutations (n = 7; 6%). Future research investigating non-genetic acquired resistance mechanisms is warranted.

PURPOSE The phase III CheckMate 722 trial (ClinicalTrials.gov identifier: NCT02864251 ) evaluated nivolumab plus chemotherapy versus chemotherapy in patients with epidermal growth factor receptor ( EGFR)–mutated metastatic non–small-cell lung cancer (NSCLC) after disease progression on EGFR tyrosine kinase inhibitors (TKIs). METHODS Patients with disease progression after first- or second-generation EGFR TKI therapy (without EGFR T790M mutation) or osimertinib (with/without T790M mutation) were randomly assigned 1:1 to nivolumab (360 mg once every 3 weeks) plus platinum-doublet chemotherapy (once every 3 weeks) or platinum-doublet chemotherapy alone (once every 3 weeks) for four cycles. Primary end point was progression-free survival (PFS). Secondary end points included 9- and 12-month PFS rates, overall survival (OS), objective response rate (ORR), and duration of response (DOR). RESULTS Overall, 294 patients were randomly assigned. At final analysis (median follow-up, 38.1 months), PFS was not significantly improved with nivolumab plus chemotherapy versus chemotherapy (median, 5.6 v 5.4 months; hazard ratio [HR], 0.75 [95% CI, 0.56 to 1.00]; P = .0528), with 9- and 12-month PFS rates of 25.9% versus 19.8%, and 21.2% versus 15.9%, respectively. Post hoc PFS subgroup analyses showed a trend favoring nivolumab plus chemotherapy in patients with tumors harboring sensitizing EGFR mutations (HR, 0.72 [95% CI, 0.54 to 0.97]), one line of previous EGFR TKI (0.72 [95% CI, 0.54 to 0.97]), or both (0.64 [95% CI, 0.47 to 0.88]). Median OS was 19.4 months with nivolumab plus chemotherapy versus 15.9 months with chemotherapy, while ORR was 31.3% versus 26.7%, and median DOR was 6.7 versus 5.6 months, respectively. Grade 3/4 treatment-related adverse events occurred in 44.7% and 29.4% of patients treated with nivolumab plus chemotherapy and chemotherapy alone, respectively. CONCLUSION Nivolumab plus chemotherapy did not significantly improve PFS versus chemotherapy in patients with EGFR-mutated metastatic NSCLC previously treated with EGFR TKIs. No new safety signals were identified.