Study	Reason for exclusion
Choi 2015	Recruited only EGFR‐mutation negative patients
Kim 2012	Gefitinib versus other EGFR TKI
Lee 2009	Open‐label, non‐randomised study
Manegold 2005	No direct comparison arm
Natale 2009	Cross‐over study
Shi 2013 ICOGEN	Gefitinib versus other EGFR TKI
Sugawara 2015	Gefitinib + chemotherapy (sequential) versus gefitinib + chemotherapy (alternating)
Urata 2016	Gefitinib versus other EGFR TKI
Zhou 2014 CTONG 0806	Recruited only EGFR‐mutation negative patients

EGFR: epidermal growth factor receptor
 TKI: tyrosine kinase inhibitor