Kunihiko Kobayashi

BACKGROUND: Non-small-cell lung cancer with sensitive mutations of the epidermal growth factor receptor (EGFR) is highly responsive to EGFR tyrosine kinase inhibitors such as gefitinib, but little is known about how its efficacy and safety profile compares with that of standard chemotherapy. METHODS: We randomly assigned 230 patients with metastatic, non-small-cell lung cancer and EGFR mutations who had not previously received chemotherapy to receive gefitinib or carboplatin-paclitaxel. The primary end point was progression-free survival; secondary end points included overall survival, response rate, and toxic effects. RESULTS: In the planned interim analysis of data for the first 200 patients, progression-free survival was significantly longer in the gefitinib group than in the standard-chemotherapy group (hazard ratio for death or disease progression with gefitinib, 0.36; P<0.001), resulting in early termination of the study. The gefitinib group had a significantly longer median progression-free survival (10.8 months, vs. 5.4 months in the chemotherapy group; hazard ratio, 0.30; 95% confidence interval, 0.22 to 0.41; P<0.001), as well as a higher response rate (73.7% vs. 30.7%, P<0.001). The median overall survival was 30.5 months in the gefitinib group and 23.6 months in the chemotherapy group (P=0.31). The most common adverse events in the gefitinib group were rash (71.1%) and elevated aminotransferase levels (55.3%), and in the chemotherapy group, neutropenia (77.0%), anemia (64.6%), appetite loss (56.6%), and sensory neuropathy (54.9%). One patient receiving gefitinib died from interstitial lung disease. CONCLUSIONS: First-line gefitinib for patients with advanced non-small-cell lung cancer who were selected on the basis of EGFR mutations improved progression-free survival, with acceptable toxicity, as compared with standard chemotherapy. (UMIN-CTR number, C000000376.)

BACKGROUND: T790M resistance mutations. Evidence suggests that the addition of chemotherapy may extend the benefits of EGFR-TKI therapy. METHODS: -mutated (exon 19 deletion or L858R mutation) advanced non-small-cell lung cancer (NSCLC) who had not previously received treatment for advanced disease to receive osimertinib (80 mg once daily) with chemotherapy (pemetrexed [500 mg per square meter of body-surface area] plus either cisplatin [75 mg per square meter] or carboplatin [pharmacologically guided dose]) or to receive osimertinib monotherapy (80 mg once daily). The primary end point was investigator-assessed progression-free survival. Response and safety were also assessed. RESULTS: A total of 557 patients underwent randomization. Investigator-assessed progression-free survival was significantly longer in the osimertinib-chemotherapy group than in the osimertinib group (hazard ratio for disease progression or death, 0.62; 95% confidence interval [CI], 0.49 to 0.79; P<0.001). At 24 months, 57% (95% CI, 50 to 63) of the patients in the osimertinib-chemotherapy group and 41% (95% CI, 35 to 47) of those in the osimertinib group were alive and progression-free. Progression-free survival as assessed according to blinded independent central review was consistent with the primary analysis (hazard ratio, 0.62; 95% CI, 0.48 to 0.80). An objective (complete or partial) response was observed in 83% of the patients in the osimertinib-chemotherapy group and in 76% of those in the osimertinib group; the median response duration was 24.0 months (95% CI, 20.9 to 27.8) and 15.3 months (95% CI, 12.7 to 19.4), respectively. The incidence of grade 3 or higher adverse events from any cause was higher with the combination than with monotherapy - a finding driven by known chemotherapy-related adverse events. The safety profile of osimertinib plus pemetrexed and a platinum-based agent was consistent with the established profiles of the individual agents. CONCLUSIONS: -mutated advanced NSCLC. (Funded by AstraZeneca; FLAURA2 ClinicalTrials.gov number, NCT04035486.).

Lung cancer is one of the leading causes of the cancer death worldwide. Gefitinib is an inhibitor of the tyrosine kinase activity of the epidermal growth factor receptor (EGFR) and has been introduced in the treatment of advanced lung cancers. The responsiveness to gefitinib has been linked to the presence of EGFR mutations. Clinical samples contain many normal cells in addition to cancer cells. A method capable of detecting EGFR mutations in a large background of wild-type EGFR genes could provide a superior clinical test. We developed a rapid and sensitive detection system for EGFR mutations named the peptide nucleic acid-locked nucleic acid (PNA-LNA) PCR clamp that can detect EGFR mutations in the presence of 100-to 1,000-fold background of wild-type EGFR. We used this method to screen 30 non-small cell lung cancer cell lines established from Japanese patients. In addition to 11 cell lines that have mutations, we found 12 cell lines in which specific mutations are observed only in the subpopulation(s) of the cells. Genetic heterogeneity of EGFR suggests that the EGFR gene is unstable in established cancers and the heterogeneity may explain variable clinical responses of lung cancers to gefitinib.