“However, there was no statistically significant difference in overall survival between the 2 groups,” the researchers report in their paper in Cancer online June 6.
Dr. Myung-Ju Ahn, at Sungkyunkwan University School of Medicine in Seoul, and colleagues explain that gefitinib has been shown to be particularly effective in patients with pulmonary adenocarcinoma, never-smokers, and patients of Asian origin – possibly because these populations are more likely to have tumors with EGFR mutations. Pemetrexed has also shown efficacy after failure of prior platinum-based chemotherapy, particularly for pulmonary adenocarcinoma.
These observations prompted the team to conduct a phase III trial comparing gefitinib with pemetrexed in 135 never-smoker Korean patients with pulmonary adenocarcinoma who had previously received platinum-based chemotherapy for advanced NSCLC.
The median progression-free survival (PFS) in the two arms was 9 months versus 3 months, respectively — a statistically significant difference (p=0.0006), the investigators found. Corresponding overall survival times were 22.2 vs 18.9 months (p=0.37).
In a subgroup analysis, the difference in PFS was more marked in the 33 patients shown to have activating EGFR mutations, at 15.7 months among those given gefitinib versus 2.9 months for patients receiving pemetrexed (p=0.005), according to the report.
Regarding safety, hematologic adverse events were rare and grade 3/4 toxicities occurred in less than 3% of patients in either arm. Both regimens were well tolerated, Dr. Ahn and colleagues note.
“In summary,” they conclude, “this study shows that second-line therapy with gefitinib compared with pemetrexed prolonged PFS and increased objective response rates without deterioration of quality of life in clinically selected patients with NSCLC.”