Table 1.

Biopsy Data, Treatment History of EGFR TKIs, and Representative Genetic Alterations From Individual Cases

Case	EGFR TKI(s) Used Before Osimertinib		Osimertinib Duration (m)	Tissue Biopsy		OCA Ver.	Representative Genetic Alterations at Rebiopsy (Tissue)					ccf DNA (Plasma)	Representative Genetic Alterations at Rebiopsy (Plasma)
	EGFR TKI(s)	Duration (m)		Baseline	Rebiopsy		EGFR Common	T790M	C797S, etc.	SNV	CN Gain		EGFR Common	T790M	C797S, etc.	SNV	CN Gain
1	A	15.4	11.6	DR	DR	1	Del19	+	C797Sa			D	Del19	+	C797S	KEAP1	EGFR, MET
2	G, E	27.1	11.1	DR	DR	1	Del19	+	C797S	NF1, GATA3	EGFR	D	Del19	+	C797S	KRAS	EGFR, MET
3	A	20.6	12.6	DR	DR	1	Del19	+	C797S		EGFR	D	Del19	+	C797S	ERBB2	EGFR, MET
4	G	46	28.6	DR	DR	1	L858R	+	C797S		EGFR	D	L858R	+	C797S		EGFR
5	A	40.7	29.1	DR	DR	3	Del19	+	C797S	MYCN		D	Del19
6	G, BE	18.9	17.6	DR	DR	1	L858R	+	G796S			D	L858R
7	G	31.6	19.8	DR	DR	1	L858R	+	C797S		CDK6	NA
8	G	24.2	13.4	D	DR	1	L858R				EGFR, MET, CDK4	D	L858R				EGFR, MET
9	G	24.4	8.8	D	DR	3	ND			BRAF, IDH2		D	ND	+
10	G, E, A	25.3	19.4	DR	DR	3	Del19				CDK4b	D	Del19
11	G, BE	24.7	18.5	DR	DR	1	L858R					NA
12	G, E, A, E, A	25.2	12.6	DR	DR	1	L858R			ATM	GAS6	D	L858R				EGFR
13	G, A	18.6	19.8	X	DR	3	Del19	+	C797Sc	PTENd		D	Del19	+	C797S		EGFR, MET
14	G	7.6	22.9	X	D	1	Del19	+	C797S	CTNNB1, SMAD4d		D	Del19	+	C797S
15	G, E	19.4	24.3	X	DR	3	L858R	+	L792V		EGFR, CDK4d	D	L858R	+	L792V		EGFR
16	G	11.7	17	R	DR	3	Del19	+	C797S	CDKN2A, IDH2d		NA
17	S	27.9	18.2	X	DR	3	Del19	+				D	Del19	+			EGFR, MET
18	E, INV	26.1	23.7	X	DR	1	Del19	+		PIK3CAd		D	Del19	+			ERBB2
19	E	35.4	19.1	X	DR	1	Del19			PIK3CAd	CDK4, CCND1d	D	Del19
20	G	33.1	23.1	R	R	1						NA

A, afatinib; BE, bevacizumab + erlotinib; ccfDNA, circulating cell-free DNA; CN, copy number; D, DNA; Del19, exon 19 deletion; DR, DNA and RNA; E, erlotinib; G, gefitinib; INV, investigational agent; NA, not available; ND, not detected; OCA, Oncomine Comprehensive Assay; R: RNA; SNV, single nucleotide variant; Ver., version; X: no data.

^aCis/trans to T790M.

^bAlso detected in baseline data.

^cTrans to T790M.

^dPossible mechanism, baseline data not available.