medwireNews: Adjuvant gefitinib does not significantly improve overall survival (OS) relative to vinorelbine plus cisplatin in patients with completely resected stage II–IIIA, EGFR-mutant non-small-cell lung cancer (NSCLC), final data from the ADJUVANT-CTONG1104 trial show.
As previously reported by medwireNews, primary analyses of the phase 3 trial, after a median 36.5 months of follow-up, indicated that disease-free survival (DFS) was significantly longer with gefitinib than with vinorelbine plus cisplatin.
The current analysis, with a median 80.0 months of follow-up, focused on the final OS data.
At this time, median OS was 75.5 months among the 111 patients who were randomly assigned to receive adjuvant gefitinib 250 mg/day for 24 months and 62.8 months among the 111 participants given vinorelbine (25 mg/m2 on days 1 and 8) plus cisplatin (75 mg/m2 on day 1) every 3 weeks for four cycles, a non-significant difference.
The corresponding 5-year OS rates of 53.2% and 51.2% were also not significantly different.
However, the updated median DFS remained significantly longer with gefitinib than with vinorelbine plus cisplatin, at 30.8 months versus 19.8 months, corresponding to a significant risk reduction in disease recurrence or death of 44%.
The 3-year DFS rates were 39.6% and 32.5% with gefitinib and vinorelbine plus cisplatin, respectively, while the 5-year rates were also comparable at 22.6% and 23.2%, respectively.
In total, 144 patients experienced disease progression or died. Of these 68.4% of 76 in the gefitinib arm and 73.6% of 68 in the vinorelbine plus cisplatin arm received subsequent therapy, with 36.8% and 51.5%, respectively, receiving targeted therapy (any tyrosine kinase inhibitor) alone or in combination with chemotherapy or local treatment.
Median OS among patients with disease progression was 76.2 months for those who received subsequent targeted therapy and 39.3 months for those who received subsequent other therapy. For the patients who did not receive subsequent therapy, the median OS was 23.4 months.
Commenting on their findings, Yi-Long Wu (Guangdong Academy of Medical Sciences, Guangzhou, China) and co-investigators say that even though the DFS advantage they observed “did not translate to a significant OS difference, OS with adjuvant gefitinib was one of the longest observed in this patient group compared with historic data.”
Writing in the Journal of Clinical Oncology, they suggest that this may be because the efficacy of subsequent treatments will contribute to OS, which “makes it increasingly challenging to achieve statistically significant differences in OS in an adjuvant setting.”
They add: “Taken together, this may support the proposition of DFS being a surrogate for OS in an adjuvant treatment setting, as currently used in breast cancer treatment.”
The authors also say that their findings, alongside those of the ADAURA trial, suggest that “it is unclear whether chemotherapy remains necessary in an adjuvant setting.”
They believe that “the standard of care for resected stage II-IIIA (N1-N2) EGFR-mutant NSCLC may be changed from adjuvant therapy to adjuvant EGFR-TKI treatment without prior adjuvant chemotherapy.”
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