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Role of Immunohistochemistry in Mutation Testing……..and one
or two other biomarkers
Prof Keith M KerrDepartment of Pathology
Aberdeen University Medical SchoolAberdeen, Scotland, UK
Personalised approach to treating cancer• Understanding the molecular basis of cancer has identified specific drivers and allowed for sub‐classification of the disease, revealing the potential for targeted agents
‘ONE SIZE FITS ALL’
Drug X
PERSONALISED THERAPY
Drug X Y Z
• Personalised treatment consists of three essential components :– Oncogenic target that drives cancer growth
– Predictive biomarker that detects presence of the target
– Well conducted clinical studies that confirm treatment efficacy in the identified patient group
Methods of biomarker analysis
Transcription
Translation
Change in DNA sequence
mRNA transcript
Protein
FISH/CISH1
DNA mutational analysis
Multiplexed genotyping
Microarray
Next‐generation sequencing
RT‐PCR
Immunohistochemistry
Biological ActivityOncogenesisDrug target
Biomarker Testing Guidelines1. Thunnissen E et al. The challenge of NSCLC diagnosis and
predictive analysis on small samples. Practical approach of a working group. Lung Cancer 2012;76:1‐18
2. Lindeman NI et al. CAP‐IASLC‐AMP guidelines on EGFR and ALK testing in NSCLC. Joint publication – J Thorac Oncol. 2013 Jul;8(7):823‐59. Also published in JMP and APLM
3. Kerr KM et al. Second ESMO consensus conference on lung cancer: pathology and molecular biomarkers for non‐small‐cell lung cancer. Annals of Oncology 25: 1681–1690, 2014
All non‐squamous tumours in patients with advanced/recurrent disease should be tested for EGFR mutation and ALK rearrangement
Selected squamous tumours (from patients with minimal or remote smoking history) should strongly be considered for testing
Other therapeutic choices driven by histology
• Pemetrexed• efficacy
• Bevacizumab• safety
• Nivolumab• licence
Securing a histological subtype in NSCLC
• Around 25% of small biopsy samples• Around 40% of cytology samples• Uncertainty about NSCLC histotype
• Predictive IHC reduces NSCLC‐NOS to under 10%
• Predict adenocarcinoma (TTF1)• Predict Squamous cell carcinoma (p40, p63, CK5/6)
Refining the diagnosis of NSCLC‐NOS
NSCLC‐NOS25‐40% of cases
TTF1p63
NSCLC – probably Squamous CaNSCLC‐Probably Adenocarcinoma
OrP40CK5/6
Immunohistochemical Subtyping of NSCLC
Immunohistochemical Subtyping of NSCLC
Predictive IHC has ‘levelled the playing field’ Better diagnosis possible on poorer specimens
25%
40%
6%
Loo PS et al,JTO 2010
Cell type EGFR mutation
KRAS mutation
BRAF mutation
ALK fusion
Adeno‐Carcinoma
15% 30.9% 2.5% 12.5%
Probable Adenoca(by IHC)
5.9% 41.8% 0 0
Squamous Carcinoma
0 0 0 0
Probable Squamous ca (by IHC)
0 0 0 0
NSCLC‐NOS 7.3% 31% 2.7% 0
Small cell carcinoma
0 0 0 1 case*
TTF‐1 positive
TTF‐1 negative
Mutations missed ifonly TTF‐1 +ve cases tested
EGFRmutation
15% 2.5% P<0.0001 5%
KRASmutation
33% 36% NS 24.8%
BRAFmutation
2.5% 2.1% NS 20%
ALK fusion
4.2% 1.3% NS 8.3%
Histology vs Mutation
TTF 1 vs Mutation
Kret A et al. Lung Cancer Jan, 2015; suppl 1
IHC and EGFR mutations
Cooper WA et al, J Clin Path 2013; 66, 744
• Mutation specific antibodies• L858R (43B2)
– Sens 86% Spec 99%
• Ex19 E746‐A750del (6B6)– Sens 100% Spec 98% for specific mutation– Sens 61% for any Ex19del
• General experience variable – L858R – 36 ‐ 100% (meta analysis 0.76)– Ex19 – Sensitivity 40 – 100% (meta analysis 0.60)– Meta‐analysis Chen Z et al. PLoS1 2014; 9, e105940
– Not comprehensive but a substitute if mutation testing not possible? Bone Biopsy? Speed?
Cooper et al, J Clin Path 2013
Kitamura A et al. Clin Cancer Res 2010; 16, 3349Kawahara A et al. Lung cancer 2011; 74, 35Simonetti S et al. J Transl Med 2010; 8, 135Brevet M et al. J Mol Diag 2010; 12, 169Chen Z et al. PLoS1 2014; 9, e105940
FLEX survival: ITT population
n=1125Survival
Median 1-year
▬ CT + cetuximab 11.3 mo 47%
▬ CT 10.1 mo 42%
HR=0.87* (95% CI 0.76–1.00), p=0.044
CT
Number of patients at riskCT + cetuximab
568 383 48 0225 134
557 383 53 3251 155
Ove
rall
surv
ival
(%)
Months
0
10
20
30
40
50
60
70
80
90
100
180 6 12 24 30
*StratifiedHR, hazard ratio; mo, months
Increased tumor response for CT + cetuximab
with EGFR IHC score ≥2001
Res
pons
e ra
te (%
)
EGFR IHC score
Selectedcut-off
CT + cetuximabCT
0 50 100 150 200 250 300
0
20
40
60
80
100
Response rate estimated for overlapping intervals of IHC score range2
1O’Byrne K, et al. CMSTO, 20102Lazar AA, et al. J Clin Oncol, 2010
Identification of discriminating EGFR IHC score threshold for cetuximab efficacy by response rate
CT CT + cetuximab
High EGFR expression (≥200) n=345
Low EGFR expression (<200)n=776
0
50
40
30
20
10
44.4
28.1
Res
pons
e ra
te (
%)
0
50
40
30
20
10
29.6 32.6
p=0.36
p=0.002
Treatment interaction test: p=0.040
O’Byrne K, et al. CMSTO, 2010
Response rate by EGFR expression level
Low EGFRIHC score <200
IHC score=112
High EGFRIHC score ≥200
IHC score=270IHC score=0
High and low EGFR expression
EGFR IHC score ranges from 0‒300
1. Hirsch FR, et al. J Clin Oncol 2003; 2. Cappuzzo F, et al. J Natl Cancer Inst 2005;3. Hirsch FR, et al. Cancer 2008; 4. Felip E, et al. Clin Cancer Res 2008;
5. Gori S, et al. Ann Oncol 2009; 6. Lee HJ, et al. Lung Cancer 2010
EGFR IHC score = [1 x (% cells 1+) + 2 x (% cells 2+) + 3 x (% cells 3+)]
1+
2+
3+
025%
50%
100%
0%
x
Staining intensity % of positive tumor cells
Calculating the EGFR IHC score1–6
Four intensities: 0 = no staining,1+ = weak, 2+ = moderate, 3+ = strong staining Intensities defined by “magnification rule” (Rüschoff et al. 2010):
Staining intensity: 3+
Staining intensity: 2+
Staining intensity: 1+ or 0
Visible by eye or under low power
examination: 4x or 5x
Needs a more detailed magnification :
10x – 20x
Needs high magnification:
40x
5x 10x 20x 40x
EGFR IHC scoring instructions
5X 40X10X
Modified from Prof. Rüschoff; Targos, Kassel
Calculating the EGFR IHC score:Using the “magnification rule”
IHC and BRAFV600E mutations
• VE1 clone– 90% V600E cases positive (n=21)– 0% non‐V600E cases positive Ilie et al, 2013
• VE1 clone– 100% V600E cases positive (n=5)– 4.8% non‐V600E cases positive (1/21) Sasaki et al, 2013
• VE1 clone vs anti‐B‐raf clone (various tumours)– VE1: 98% sens, 97% spec– Anti‐B‐raf: 95% sens, 83% spec Routhier et al, 2013
• Can we ignore the non‐V600E mutations? Smit E, 2014
Ilie et al. Ann Oncol 2013; 24, 742‐748
Ilie et al. Ann Oncol 2013; 24, 742‐748Sasaki et al Lung Cancer 2013; 82, 51‐54Routhier et al, Hum Pathol 2013; 44, 2563‐2570Smit E, J Thorac Oncol 2014; 9,1594‐5
HGF Ligand binding c-MET dimerization
GAB1 the major substrate of activated ‘pMET’
Oncogenesis ‘Reactivation’ of
embryogenetic mechanisms Disrupted tissue homeostasis Motility and ‘invasiveness’
Activation Not mutation Upregulation,
exaggerated physiology Inducable
Comoglio et al. Nat Rev Drug Discov 2008;7:504-16
MET as an oncogene
MET assessment: Gene copy number or protein IHC?
Anti- MET agents
Small molecule MET TKIs – ARQ197 (Tivantinib)
Anti-MET monoclonal antibodies -MetMab
Spigel et al, ESMO 2010
Spigel et al,J Clin Oncol 2013
MET HIGH = Positive MET LOW = Negative
T cell activation can be augmented bytargeting immune checkpoints
• T‐cell responses are regulated though a complex balance of inhibitory (“checkpoints”) and activating signals
• Tumours can dysregulate checkpoints and activating pathways, and consequently the immune response
• Targeting checkpoints and activating pathways is an innovative approach to cancer therapy, designed to promote an immune response
PD‐1
CTLA‐4
Inhibitory receptors
Activating receptors
TIM‐3
LAG‐3
T‐cell activity
CD28
OX40
CD137
Adapted from Mellman I, et al. Nature 2011:480;481–9; Pardoll DM. Nat Rev Cancer 2012;12:252–64
High levels if PD1 or PDL1 protein expression (IHC) may inhibitImmune response
Block PD1 or PDL1Immune damage to tumour
Chen, et al. Clin Cancer Res 2012
Biomarkers for Immunotherapy?Biomarkers for Immunotherapy?
PD-L1 Negative PD-L1 Positive (predictive of response)
Less response More response
?1% 5% 10% 50% cell positive
Intensity of staining?Immune cell staining?Several therapeutics
Several companion diagnostics…………
Kerr KM et al. JTO pub online March 2015
PD‐L1 as a predictive immune biomarker: assays,sample collection and analysis in NSCLC studies
PD‐L1
Assay
Sample Source and
Co
llection
Definition
of P
ositivity
†
PembrolizumabMerck
• Prototype or clinical trial IHC assay (22C3 Ab)1,2
• Surface expression of PD‐L1 on tumour specimen1,2
• Ph I: Fresh or archival tissue1,2
IHC Staining:• Strong vs weak expression1,2• PD‐L1 expression required for
NSCLC for enrollment1• Note that one arm of KEYNOTE 001 trial requires PD‐L1‐ tumours1
Tumour PD‐L1 expression:1,2 • ≥50% PD-L1+ cut-off:
32% (41/129)• 1–49% PD-L1+ cut-off: 36%
(46/129)
NivolumabBristol‐Myers Squibb
• Dako automated IHC assay (28‐8 Ab)3,4
• Surface expression ofPD‐L1 on tumour cells3,4
• Archival or fresh tissue3,4
IHC Staining:• Strong vs weak expression3,4• Patients not restricted by PD‐L1
status in 2nd‐ & 3rd‐line• Ph III 1st‐line trial in
PD‐L1+5
Tumour PD‐L1 expression:• 5% PD‐L1+ cut‐off: 59% (10/17)3• 5% PD‐L1+ cut‐off: 49% (33/68)4
MPDL3280ARoche/Genentech
• Central laboratory IHC assay6
• Surface expression of PD‐L1 on TILs or tumour cells6,7
• Archival or fresh tissue6
IHC Staining Intensity (0, 1, 2, 3):• IHC 3 (≥10% PD‐L1+)6,7• IHC 2,3 (≥5% PD‐L1+)6,7• IHC 1,2,3 (≥1% PD‐L1+)6,7• IHC 0,1,2,3 (all patients with
evaluable status)6,7• PD‐L1 expression required for
NSCLC for enrolment in Ph II trials6• x
TIL PD‐L1 expression:6• IHC 3 (≥10% PD‐L1+): 11% (6/53)
• PD‐L1 low(IHC 1, 0): 62% (33/53)
MEDI4736AstraZeneca
• Ventana automated IHC (BenchMark ULTRA using Ventana PD‐L1 (SP263) clone)8,9
• Surface expression of PD‐L1 on tumour cells8,9
• Unknown
IHC Staining Intensity:• Not presented to date8–10
Tumour PD‐L1 expression (all doses):8• PD‐L1+: 34% (20/58)• PD‐L1‐: 50% (29/58)
†Definition of PD‐L1 positivity differs between assay methodologies.1. Garon EB, et al. Presented at ESMO 2014 (abstr. LBA43); 2. Rizvi NA, et al. Presented at ASCO 2014 (abstr. 8007); 3. Gettinger S et al. Poster p38 presented at ASCO 2014 (abstr. 8024);
4. Brahmer JR et al. Poster 293 presented at ASCO 2014 (abstr. 8112^); 5. http://www.clinicaltrials.gov/ct2/show/NCT02041533 Accessed January 2015;6 . Rizvi NA et al. Poster presented at ASCO 2014 (abstr. TPS8123); 7. Soria J‐C, et al. ESMO 2014 (abstr. 1322P); 8. Brahmer JR, et al. Poster presented at ASCO 2014 (abstr. 8021^);
9. Segal NH, et al. Presented at ASCO 2014 (abstr. 3002^); 10. Segal NH, et al. ESMO 2014 (abstr. 1058PD).
Ab, antibody; IHC, immunohistochemistry
Other markers to consider…..
• HER2– No ligand binding domain. Important heterodimerisation– Mutation (0.8‐4.3%), ˄Gene Copy # (38‐43%), – Amplification (~2%), Over‐expression (24‐35%)– Gefitinib, Pan‐HER inhibitors, Traztuzamab?
• PTEN– Loss of tumour suppressor gene activity– Prognostic effect– PI3K/AKT inhibitors?
• RANK and RANK‐L– Bone metastatic disease– Denosumab
Hirsch et al. Oncogene 2009Hirsch et al, Br J Can 2002Soh et al, Int J Can 2007Suzuki et al, Lung Cancer 2015Reis et al, Lung Cancer 2015
Panel of 54 genes with potentially druggable alterations
Govindan et al. Cell. 2012 Sep 14;150:1121‐34
IHC and cytotoxic agents• ERCC1
– Resistance factor in platinum based chemotherapy– Suggestions of a predictive benefit in several studies Olaussen et al. NEJM 2006
– Specificity of antibody (clone 8F1) Friboulet et al. NEJM 2013
• Tubulin III– Associated with responses to taxanes– Variable results
• Thymidylate Synthase (TS)– Target of pemetrexed– IHC scores for TS predictive of response Nicholson et al J Thorac Oncol 2013
• Diagnostic IHC• Predictive markers
– Mutated proteins– WT proteins
Role of Immunohistochemistry in Mutation Testing……..and one or two
other biomarkers