Implications and potential next steps
Despite the lack of OS improvement with gefitinib, “all of the patients on this study did much, much better than historical non–small cell lung cancer not specified by the EGFR mutation, with 70 months median survival compared to 35 months median survival for N2-positive disease,” said invited discussant Christopher G. Azzoli, MD, director of thoracic oncology at Lifespan Cancer Institute at Brown University in Providence, R.I.
“But you can’t avoid noticing how the curves come back together in terms of disease-free survival when your effective treatment is limited to 24 months,” he added.
An apparent risk of late brain recurrence in the gefitinib arm is also a concern, Dr. Azzoli said. “So ... longer duration of treatment with a drug that has better control of CNS [central nervous system] disease, such as osimertinib, may improve both DFS and OS,” he added.
Only about 50% of patients in the chemotherapy arm received a TKI at recurrence. The post hoc analysis showing that TKI recipients had the best outcomes raises the question of whether “the survival benefit could be conferred by delivering a superior drug merely at recurrence, or is there benefit to earlier delivery of an effective drug,” Dr. Azzoli said.
Given the high cost of continuous therapy, biomarker refinement could help improve treatment decision-making, he said, noting that “early testing of blood DNA to detect cancer in the body as minimal residual disease is showing promise,” and that many phase 3 studies of EGFR-TKIs are ongoing.
The current trial was sponsored by the Guangdong Association of Clinical Trials. Dr. Wu disclosed relationships with AstraZeneca, Boehringer Ingelheim, Bristol-Myers Squibb/China, Lilly, MSD Oncology, Pfizer, and Roche. Dr. Azzoli reported having no disclosures.
SOURCE: Wu Y et al. ASCO 2020, Abstract 9005.