Tumor heterogeneity and resistance to EGFR-targeted therapy in advanced nonsmall cell lung cancer: challenges and perspectives

Figures & data

Table 1 Distribution of known tumor-driving mutations and chromosomal fusions in advanced NSCLC

Mutation/fusion	Estimated frequency, %
Gene mutations
EGFR	10–30
TP53	20–25
KRAS	15–25
BRAF	1–3
PIK3CA	2–3
AKT1	1
MAP2K1	1
HER2	2
MET	<1
Chromosomal fusions
EML4-ALK	3–7
RET	1–2
ROS1	1–2
Unknown

Note: Data obtained from previous reports.^{54,55,70–73}

Abbreviations: NSCLC, nonsmall cell lung cancer; EGFR, epidermal growth factor receptor; TP53, tumor protein p53; KRAS, Kirsten rat sarcoma viral oncogene homolog; BRAF, v-raf murine sarcoma viral oncogene homolog B; ALK, anaplastic lymphoma kinase; PIK3CA, phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha; AKT1, v-akt murine thymoma viral oncogene homolog 1; MAP2K1, mitogen-activated protein kinase 1; HER2, human epidermal growth factor receptor 2.

Figure 1 Tumor-driving mutations in the tyrosine kinase domain of EGFR (epidermal growth factor receptor).

Notes: The most common EGFR mutations are in-frame deletions (Del) in exon 19 (45%–50%), which remove four high conserved amino acid residues (the LREA motif) of EGFR, and a point mutation in exon 21 (40%–45%), causing substitution of an arginine by a leucine (L858R). Both of them are sensitive to tyrosine kinase inhibitors (TKIs). Other TKI-sensitive mutations include point mutations such as G719X in exon 18 and L861X in exon 21. In contrast, patients harboring a T790M point mutation or in-frame insertions (Ins) in exon 20 are less sensitive to TKIs. T790M mutation is also an important mechanism in acquired TKI resistance. Data were derived from previous reports.^{54,59,60,76,77}

Table 2 Temporal tumor heterogeneity and acquired TKI resistance in advanced NSCLC

Mechanisms	Estimated frequency, %		References
	Before TKIs	After TKIs
Resistant EGFR mutations
T790M	1–2	50	^Citation57,Citation97,Citation109,Citation139
D761Y, L747S, and T854A	<1	<5	^Citation12,Citation76
Bypass signaling
MET amplification	<5	5–20	^Citation12,Citation130,Citation139
HGF overexpression	30	60	^Citation140,Citation141
HER2 amplification	2	12	^Citation142
PIK3CA mutations	2–3	5	^Citation112,Citation143
CRKL amplification	3	9	^Citation144,Citation145
Phenotypic changes
Small-cell transformation	<1	3–14	^Citation57,Citation112
EMT	<1	20–44	^Citation26,Citation133

Abbreviations: TKI, tyrosine kinase inhibitor; NSCLC, nonsmall cell lung cancer; EGFR, epidermal growth factor receptor; HGF, hepatocyte growth factor; HER2, human epidermal growth factor receptor 2; PIK3CA, phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha; CRKL, CRK-like protein gene; EMT, epithelial-mesenchymal transition.

Table 3 Clinical trials of next-generation TKIs in advanced NSCLC

Targets and trial code	Trial Phase	Lines of treatment	EGFR mutations	Trial design	Outcomes	References
Second-generation irreversible TKIs
Afatinib (BIBW2992)
EGFR/HER2
LUX-Lung 1	IIb/III	Third/fourth	Unselected	Afatinib versus placebo in Asian patients	Improved PFS (3.3 versus 1.1 months) and ORR (7% versus 0.5%), no benefit in term of OS	^Citation187
LUX-Lung 2	II	First/second	Positive	Afatinib after chemotherapy	ORR, 61%	^Citation190
LUX-Lung 3	III	First	Positive	Afatinib versus pemetrexed + cisplatin	Improved PFS (11.1 versus 6.9 months)	^Citation188
LUX-Lung 4	II	Second	Positive in 72.6% of patients	Afatinib after TKIs	ORR, 8.2%; median PFS: 4.4 months; median OS, 19 months	^Citation186
LUX-Lung 5	III	Second	Unselected	Afatinib + chemotherapy versus chemotherapy after afatinib	Ongoing
LUX-Lung 6	III	First	Positive	Afatinib versus gemcitabine + cisplatin in Asian patients	Improved PFS (11.0 versus 5.6 months)	^Citation189
Dacomitinib (PF00299804)
EGFR/HER2/HER4
NCT00769067	II	Second/third	Unselected	Dacomitinib versus erlotinib after chemotherapy	Improved median PFS (2.86 versus 1.91 months) and median OS (9.53 versus 7.44 months)	^Citation191
NCT00548093	II	Second/third	Positive	Dacomitinib	ORR, 8%; median PFS, 18 weeks	^Citation196
Neratinib (HKI-272)
EGFR, HER2
Canertinib (CI-1033)
EGFR/HER2/HER4
NCT00266877	II	Second	Positive	Neratinib after TKIs	ORR, 3% (all in patients with G719X mutation)	^Citation193
NCT00050830	II	Second	Unselected	CI-1033 after chemotherapy	1-year survival rate, 26%–29%; ORR, 2%–4%	^Citation197
N/A	I/II	First	Unselected	CI-1033 + paclitaxel + carboplatin	ORR, 26%; median PFS, 5.1 months; median OS, 12.4 months	^Citation198
Third-generation irreversible TKIs
CO-1686/
EGFR (T790M mutation)
NCT01526928	I/II	Second	Positive	CO-1686 after TKIs	Ongoing
AZD9291/
EGFR (T790M mutation)
NCT01802632	I/II	Second	Positive	AZD9291 after TKIs	Ongoing
NCT02094261	II	Second	Positive	AZD9291 in patients with T790M mutation after TKIs	Ongoing
WZ4002/
EGFR (T790M mutation)	Preclinical

Abbreviations: TKI, tyrosine kinase inhibitor; NSCLC, nonsmall cell lung cancer; EGFR, epidermal growth factor receptor; HER2, human epidermal growth factor receptor 2; PFS, progression free survival; ORR, overall response rate; OS, overall survival; HER4, human epidermal growth factor receptor 4.

Figure 2 Schematic summary of measures to overcome tumor heterogeneity and drug resistance in lung cancer.

Notes: Spatial heterogeneity indicates inter-/intratumor differences at the genomic, epigenetic, and proteomic levels, whereas temporal heterogeneity reflects dynamic tumor evolution over time. Some diagnostic and therapeutic approaches have been validated in patients for clinical translation.
Abbreviation: TKI, tyrosine kinase inhibitors.

PaoWChmieleckiJRational, biologically based treatment of EGFR-mutant non-small-cell lung cancerNat Rev Cancer2010101176077420966921

 PubMed Web of Science ®Google Scholar

PaoWGirardNNew driver mutations in non-small-cell lung cancerLancet Oncol201112217518021277552

 PubMed Web of Science ®Google Scholar

LiTKungHJMackPCGandaraDRGenotyping and genomic profiling of non-small-cell lung cancer: implications for current and future therapiesJ Clin Oncol20133181039104923401433

 PubMed Web of Science ®Google Scholar

SequistLVHeistRSShawATImplementing multiplexed genotyping of non-small-cell lung cancers into routine clinical practiceAnn Oncol201122122616262422071650

 PubMed Web of Science ®Google Scholar

MarchettiAMartellaCFelicioniLEGFR mutations in non-small-cell lung cancer: analysis of a large series of cases and development of a rapid and sensitive method for diagnostic screening with potential implications on pharmacologic treatmentJ Clin Oncol200523485786515681531

 PubMed Web of Science ®Google Scholar

KosakaTYatabeYEndohHKuwanoHTakahashiTMitsudomiTMutations of the epidermal growth factor receptor gene in lung cancer: biological and clinical implicationsCancer Res200464248919892315604253

 PubMed Web of Science ®Google Scholar

SharmaSVBellDWSettlemanJHaberDAEpidermal growth factor receptor mutations in lung cancerNat Rev Cancer20077316918117318210

 PubMed Web of Science ®Google Scholar

WuJYYuCJChangYCYangCHShihJYYangPCEffectiveness of tyrosine kinase inhibitors on “uncommon” epidermal growth factor receptor mutations of unknown clinical significance in non-small cell lung cancerClin Cancer Res201117113812382121531810

 PubMed Web of Science ®Google Scholar

YuHAArcilaMERekhtmanNAnalysis of tumor specimens at the time of acquired resistance to EGFR-TKI therapy in 155 patients with EGFR-mutant lung cancersClin Cancer Res20131982240224723470965

 PubMed Web of Science ®Google Scholar

InukaiMToyookaSItoSPresence of epidermal growth factor receptor gene T790M mutation as a minor clone in non-small cell lung cancerCancer Res200666167854785816912157

 PubMed Web of Science ®Google Scholar

ArcilaMEOxnardGRNafaKRebiopsy of lung cancer patients with acquired resistance to EGFR inhibitors and enhanced detection of the T790M mutation using a locked nucleic acid-based assayClin Cancer Res20111751169118021248300

 PubMed Web of Science ®Google Scholar

LiHHuHWangRPrimary concomitant EGFR T790M mutation predicted worse prognosis in non-small cell lung cancer patientsOnco Targets Ther20143;7513524

 Web of Science ®Google Scholar

GainorJFShawATEmerging paradigms in the development of resistance to tyrosine kinase inhibitors in lung cancerJ Clin Oncol201331313987399624101047

 PubMed Web of Science ®Google Scholar

EngelmanJAZejnullahuKMitsudomiTMET amplification leads to gefitinib resistance in lung cancer by activating ERBB3 signalingScience200731658271039104317463250

 PubMed Web of Science ®Google Scholar

YanoSWangWLiQHepatocyte growth factor induces gefitinib resistance of lung adenocarcinoma with epidermal growth factor receptor-activating mutationsCancer Res200868229479948719010923

 PubMed Web of Science ®Google Scholar

YanoSYamadaTTakeuchiSHepatocyte growth factor expression in EGFR mutant lung cancer with intrinsic and acquired resistance to tyrosine kinase inhibitors in a Japanese cohortJ Thorac Oncol20116122011201722052230

 PubMed Web of Science ®Google Scholar

MazièresJPetersSLepageBLung cancer that harbors an HER2 mutation: epidemiologic characteristics and therapeutic perspectivesJ Clin Oncol201331161997200323610105

 PubMed Web of Science ®Google Scholar

SequistLVWaltmanBADias-SantagataDGenotypic and histological evolution of lung cancers acquiring resistance to EGFR inhibitorsSci Transl Med201137575ra26

 PubMed Web of Science ®Google Scholar

WangLHuHPanYPIK3CA mutations frequently coexist with EGFR/KRAS mutations in non-small cell lung cancer and suggest poor prognosis in EGFR/KRAS wildtype subgroupPLoS ONE201492e8829124533074

 PubMed Web of Science ®Google Scholar

CheungHWDuJBoehmJSAmplification of CRKL induces transformation and epidermal growth factor receptor inhibitor resistance in human non-small cell lung cancersCancer Discov20111760862522586683

 PubMed Web of Science ®Google Scholar

KimYHKweiKAGirardLGenomic and functional analysis identifies CRKL as an oncogene amplified in lung cancerOncogene201029101421143019966867

 PubMed Web of Science ®Google Scholar

ShienKToyookaSYamamotoHAcquired resistance to EGFR inhibitors is associated with a manifestation of stem cell-like properties in cancer cellsCancer Res201373103051306123542356

 PubMed Web of Science ®Google Scholar

UramotoHIwataTOnitsukaTShimokawaHHanagiriTOyamaTEpithelial-mesenchymal transition in EGFR-TKI acquired resistant lung adenocarcinomaAnticancer Res20103072513251720682976

 PubMed Web of Science ®Google Scholar

MillerVAHirshVCadranelJAfatinib versus placebo for patients with advanced, metastatic non-small-cell lung cancer after failure of erlotinib, gefitinib, or both, and one or two lines of chemotherapy (LUX-Lung 1): a phase 2b/3 randomised trialLancet Oncol201213552853822452896

 PubMed Web of Science ®Google Scholar

YangJCShihJYSuWCAfatinib for patients with lung adenocarcinoma and epidermal growth factor receptor mutations (LUX-Lung 2): a phase 2 trialLancet Oncol201213553954822452895

 PubMed Web of Science ®Google Scholar

SequistLVYangJCYamamotoNPhase III study of afatinib or cisplatin plus pemetrexed in patients with metastatic lung adenocarcinoma with EGFR mutationsJ Clin Oncol201331273327333423816960

 PubMed Web of Science ®Google Scholar

KatakamiNAtagiSGotoKLUX-Lung 4: a phase II trial of afatinib in patients with advanced non-small-cell lung cancer who progressed during prior treatment with erlotinib, gefitinib, or bothJ Clin Oncol201331273335334123816963

 PubMed Web of Science ®Google Scholar

WuYLZhouCHuCPAfatinib versus cisplatin plus gemcitabine for first-line treatment of Asian patients with advanced non-small-cell lung cancer harbouring EGFR mutations (LUX-Lung 6): an open-label, randomised phase 3 trialLancet Oncol201415221322224439929

 PubMed Web of Science ®Google Scholar

RamalingamSSBlackhallFKrzakowskiMRandomized phase II study of dacomitinib (PF-00299804), an irreversible pan-human epidermal growth factor receptor inhibitor, versus erlotinib in patients with advanced non-small-cell lung cancerJ Clin Oncol201230273337334422753918

 PubMed Web of Science ®Google Scholar

ReckampKLGiacconeGCamidgeDRA phase 2 trial of dacomitinib (PF-00299804), an oral, irreversible pan-HER (human epidermal growth factor receptor) inhibitor, in patients with advanced non-small cell lung cancer after failure of prior chemotherapy and erlotinibCancer201412081145115424501009

 PubMed Web of Science ®Google Scholar

SequistLVBesseBLynchTJNeratinib, an irreversible pan-ErbB receptor tyrosine kinase inhibitor: results of a phase II trial in patients with advanced non-small-cell lung cancerJ Clin Oncol201028183076308320479403

 PubMed Web of Science ®Google Scholar

JännePAvon PawelJCohenRBMulticenter, randomized, phase II trial of CI-1033, an irreversible pan-ERBB inhibitor, for previously treated advanced non small-cell lung cancerJ Clin Oncol200725253936394417761977

 PubMed Web of Science ®Google Scholar

ChiapporiAAEllisPMHammJTA phase I evaluation of oral CI-1033 in combination with paclitaxel and carboplatin as first-line chemotherapy in patients with advanced non-small cell lung cancerJ Thorac Oncol2006191010101917409987

 PubMed Web of Science ®Google Scholar