Molecular Testing in Lung Cancer

Transcription

1 Molecular Testing in Lung Cancer Pimpin Incharoen, M.D. Assistant Professor, Thoracic Pathology Department of Pathology, Ramathibodi Hospital

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3 Genetic alterations in lung cancer Source: Khono et al, Trans Lung Cancer Res, 2015.

4 Resection specimen FFPE H&E

5 Biopsy: Bronchoscope + biopsy

6 Biopsy: TTNB

7 Smeared slide Fixed with 95% alcohol Stain with Papanicolaou s stain

8 Cytology specimens: Pleural fluid Cell block with FFPE tissue and H&E section

9 must-test category genes EGFR ALK ROS1 second-category genes BRAF KRAS MET ERBB2 [HER2] RET

10 Chen et al, Modern Pathology, 2012 EGFR mutation subtypes

11 Direct sequencing

12 Real time PCR (qpcr)

13 Commercial kit 42 mutations 29 mutations

14 ALK gene rearrangement Macmillan Publishers Ltd. Nature 2007;448(7153):

15 Macmillan Publishers Ltd. Nature 2007 ALK gene fusion variants

16 Incharoen et al, World J Surg Onco, 2016 ALK IHC (D5F3)

17 Incharoen et al, World J Surg Onco, 2016 ALK FISH

18 Immunohistochemistry is an equivalent alternative to FISH for ALK testing

19 ROS-1 2-3% of lung adenocarcinoma Crizotinib treatment: 72% response rate and 19.2 months median PFS (Shaw, et al. N Engl J Med. 2014) the FDA approved in 2016 associated with light to never smoking history no requirement of a companion diagnostic

20 ROS-1 fusion variants

21 ROS-1 testing Screening IHC; clone D4D6 RT-PCR and FISH for confirmation 5 studies compare IHC and FISH 1 study compare IHC and RT-PCR

22 Boyle et al, Clin Lung Cancer, 2015 ROS-1 IHC

23 Shan L et al, Plos One, 2015 ROS-1 FISH

24 Additional genes BRAF RET HER-2 KRAS MET

25 BRAF larger testing panels when routine EGFR, ALK, and ROS1 testing is negative more frequent in adenocarcinomas than in squamous cell carcinomas mutually exclusive of KRAS, EGFR, or ALK 0.5% to 4.9% BRAF mutations in lung cancer V600E non-p.v600e other codon 600; V600K exon 15 codons 466 and 469 in exon 11

26 BRAF phase II single-arm clinical trial (Planchard D et al, Lancet Oncol, 2016) single-agent dabrafenib; response rate of 33% partial RR and 58% disease control rate combination dabrafenib trametinib; 63% partial RR of and 75% disease control rate FDA approval was granted in 2017

27 RET 0.6% to 0.9% of NSCLCs 1.2% to 2% of adenocarcinomas fuse the tyrosine kinase domain of RET with coiled-coil dimerization domains of various partner genes

28 RET fusion variants 90%

29 RET IHC (ab134100, Abcam, Cambridge, United Kingdom) RET FISH narrow spacing between the split probe signals (1 signal diameter distance) 15% of cells with split signals or single 3 probe signals RET kinase is being explored in phase II clinical trials

30 HER-2 2-3% of Sequence alterations; In-frame insertions in exon 20 and substitutions at S % of gene amplification De novo Resistance following treatment with EGFR TKIs phase II trial (Kris MG et al, Oncol, 2015); durable responses to dacomitinib in patients with specific HER2 mutations routine stand alone testing for ERBB2 mutations is not indicated outside a clinical trial

31 KRAS 20% to 30% of lung adenocarcinomas more frequently in people with tobacco exposure codon 12 and 13, less commonly in codon 61 and 146 Therapies have not been proven clinically effective phase II study of selumetinib + docetaxel results 37% objective RR Selumetinib Evaluation as Combination Therapy-1 (SELECT- 1) phase III trial failed to demonstrate an outcome benefit phase II study of selumetinib + erlotinib failed to show response to selumetinib independent of erlotinib

32 MET MET amplification associated with poor outcome resistance following treatment with EGFR TKIs MET exon 14 mutation wide variability and complexity of mutations require NGS-based assays MET amplification or MET exon 14 mutation are sensitive to crizotinib in some cases

33 MET MET amplification detection Screenning IHC (clone SP44) 5MET signals/cell and a MET:CEP7 2 (high level amplification) showed a response to crizotinib Phase II study of combination of gefitinib and capmatinib (Wu Y-L et al, J Clin Oncol, 2014); 40% RR in patients with acquired EGFR TKI resistance 5

34 Next-Generation Sequencing Multiplexed genetic sequencing panels to identify other treatment options beyond EGFR, ALK and ROS1 NGS Separation of individual DNA molecules PCR amplification of predetermined regions of the genome parallel sequencing of each of the amplified single DNA on a massive scale computational data processing to recombine and identify the sequences provide a digital display of each sample s genomic features

35 Next-Generation Sequencing must-test genes in lung cancer EGFR, ALK, ROS1 the genes suggested for inclusion in larger panels BRAF, RET, ERBB2 (HER2), KRAS, MET other genes that may have potential roles in cancer development

36 What Testing Is Indicated for Patients With Targetable Mutations Who Have Relapsed on Targeted Therapy? EGFR T790M testing should be used to guide selection of treatment with osimertinib Laboratories testing should deploy assays capable of detecting T790M mutations in 5% of EGFR alleles MET or HER2 amplification detection; more effectively targeted by other agents C797S; not recommended for routine management arise in tumors that have progressed after osimertinib treatment for T790M disease rare and poorly studied not currently treatable

37 What Testing Is Indicated for Patients With Targetable Mutations Who Have Relapsed on Targeted Therapy? ALK acquired resistance mutations Crizotinib; L1152R, C1156Y, F1174L, L1196M, L1198P, D1203N, and G1269A second-line ALK inhibitors; G1202R, G1202del, V1180L, S1206Y and E1201K data are still limited and insufficient current practice no testing for secondary ALK mutations is required

38 What Is the Role of Testing for Circulating cfdna for Lung Cancer Patients? Ramathibodi s Research results Early stage Concordance 58.6% Sensitivity 14.3% Specificity 100% Late stage Concordance 87.5% Sensitivity 83% Specificity 100% T790M acquired mutation after treated with primary EGFR TKIs - 40%

39 What Is the Role of Testing for Circulating cfdna for Lung Cancer Patients? tissue is limited and/or insufficient for molecular testing to identify EGFR T790M mutations in lung adenocarcinoma patients with progression or clinical resistance to EGFR-targeted TKIs testing of the tumor sample is recommended if the plasma result is negative.

40 The Role of Testing to Select Patients for Treatment With Immunomodulatory Therapies Sao MS et al, IASLC 18th World Conference on Lung Cancer

41 JTO, November 2017 Serial sections from tissue microarrays from 100 lung adenocarcinomas, stained and scored in four centers. The overall concordances between 22C3 and SP263 data were 0.99

42 TC >50%

43 Ramathibodi data January 2017 to October 2017 PDL-1 IHC 22C3 assay 64 cases 14 50%) 10 adenocarcinoma 1 squamous cell carcinoma 1 adenosquamous carcinoma 1 NSCLC, NOS 10 weak positive (TPS 1-49%) 40 negative

44 Summary allow testing of cytology samples recommend against the use of immunohistochemistry for EGFR testing include ROS1 testing for all adenocarcinoma patients inclusion of additional genes (HER2, MET, BRAF, KRAS, and RET) for laboratories that perform NGS panels Use IHC as an alternative to FISH for ALK and/or ROS1 testing

45 Summary Use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors Use of cell-free DNA to rule in targetable mutations when tissue is limited or hard to obtain. Use PD-L1 IHC clone 22C3 or SP263 for selective anti-pd1 or PDL-1 drugs