The IMPRESS trial asks a simple question: Should you continue an [epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor] while you switch to chemotherapy,” said Solange Peters, MD, PhD, Head of the Thoracic Malignancies Program at the University of Lausanne, Switzerland, at the European Society for Medical Oncology (ESMO) 2014 Congress. Dr. Peters was formal discussant of the study at the ESMO meeting.

“This was a well conducted trial restricted to EGFR-mutated non–small cell lung cancer with known sensitivity to gefitinib. There were imbalances, with higher response rates in placebo arm patients and older patients as well as more brain metastasis in the gefitinib arm. The [progression-free survival] is absolutely similar and in line with what we expect in unselected patients, even when data were adjusted for these covariates, in an exploratory post hoc anaylsis regarding brain metastasis,” she said.

The overall survival difference is around 3 months in favor of the placebo arm. “Knowing that survival data are immature, the placebo arm appears to be performing significantly better than the experimental arm,” Dr. Peters commented. “Importantly, more patients in the placebo arm received subsequent postprogression platinum-based chemotherapy or EGFR [tyrosine kinase inhibitor] rechallenge, partially explaining for such difference. We don’t know why these imbalances were present,” she added.

Possible Strategy

A possible strategy in the patient population of IMPRESS might be a sequential EGFR tyrosine kinase inhibitor rechallenge (ie, reintroduction after intervening treatment) rather than continuation. “Several retrospective analyses show consistent activity,” she said. “There are several other potential treatment strategies, but this study showed us that we should not combine EGFR tyrosine kinase inhibitors with chemotherapy in this setting. A platinum-based chemotherapy doublet remains a standard of care,” she stated. ■

Disclosure: Dr. Peters reported no potential conflicts of interest.