pd‐l1 immunohistochemistryas a predictivebiomarker: pros ... · othermethodsforpd‐l1 detection...
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PD‐L1 immunohistochemistry as a predictive biomarker: pros and cons
Edurne ArriolaHead of Lung CancerMedical OncologyHospital del Mar
20/10/17
Outline
• Current status (lung cancer)• Pros
– Predictive value for enrichment
• Cons– Lack of predictive value for exclusion– Technical issues– Complexity of immune response
Currently available assays
Hirsch F, WCLC 2017
PD‐L1 scoring
Are they comparable?
Blueprint 2A. M Tsao, WCLC 2017
Are they comparable?Study Assays
comparedSamples analyzed
Number of scorers
Comparabilityon TC
Comparabilityon IC
Hirsch(Blueprint 1,2)
28‐8, 22C3, SP142, SP263
39 resectedNSCLC
3 28‐8, 22C3, SP263 similar;SP142 stain fewer TC
More variable staining of IC for all assays
Scheel(german)
28‐8, 22C3, SP142, SP263
15+15 resectedNSCLC
9 28‐8, 22C3 similar; SP142 lower; SP263 higher
Low concordance(k<0.12)
Rimm(NCCN)
28‐8, 22C3, SP263
90 resected NSCLC
13 High k across 28‐8, 22C3;SP142 lower
Low correlation(k=0.19)
Ratcliffe(AstraZeneca)
28‐8, 22C3, SP263
493 excisedNSCLC
1 91‐97% agreement between assays
Not assessed
Adam (French) 28‐8, 22C3, SP142, SP263
41 resectedNSCLC
7 K>0.75 for threshold 1 and 5%
Overallagreement 75‐90%
Blueprint 2A. M Tsao, WCLC 2017
22C3, 28.8 and SP263 highly concordantSP142 stains less and 73‐10 more
Tumor cells
Reliability among pathologists
Moderate to strong for tumor cells
What happens with IC?
Hirsch, WCLC 2017
Poor reliability for immune cells
Blueprint 2A. M Tsao, WCLC 2017
Do these differences have an impact in scoring?
It does for SP142 in intermediate scoring category 1‐49%
Discordance is lower in high expressors
Is PD‐L1 clinically relevant?
M Tsao, WCLC 2017
It is required for pembrolizumab prescription
Higher expression predicts for increased benefit
PembrolizumabAtezolizumab
First line therapy in PD‐L1 selected NSCLC
Carcereny WCLC 2017; Brahmer WCLC &NEJM 2017; Carbone Lancet 2017
Nivolumab
But, can we deny treatment to PD‐L1 negative (<1%)?
• In our experience 50% patients are negative (IOdetect platform)
• The vast majority (77%, 115 out of 150 patients) of SP142 PD‐L1 negative patients were also PD‐L1 negative by the 22C3 assay
17 Gadgeel S, et al. 22C3 vs SP142 in OAK
SP142 Assay
Dx–, n Dx+, n
22C3 Assay
Dx–, n 115 103
Dx+, n 35 145
Dx–, no or low PD‐L1 expression; Dx+, positive for PD‐L1 expression.
N = 103 N = 115 N = 3522C3
TPS < 1%SP142
TC0 and IC0
N = 218N = 150
115 patients PD-L1–negative by 22C3 and SP142
Double negative
NegativeBy 22C3
NegativeBy SP142
Is it an antibody problem?
Does not seem so…
Gadgeel et al. ESMO 2017
Could it be the sampling?
Blueprint 2A. M Tsao, WCLC 2017
Heterogeneity and dynamic expressionmight impact
• Expression heterogeneity: Spatial/temporal heterogeneity
Casadevall et al. CLC 2017; Uruga et al. JTO 2017; Pinato et al. Oncoimmunology 2016
Other methods for PD‐L1 detectionPD‐L1 mRNA
PD‐L1 low
< median expression(n=355)
PD‐L1 high
≥ median expression(n=356)
OS HR0.68
OS HR0.74
OAK trial PD‐L1 gene expression
PD-L1 gene expression
Median OS, months Atezolizumab
Docetaxel
PD-L1 high 16.3 11.3PD-L1 low 12.7 8.7Biomarker evaluable (n=711) 14.2 9.5
Data presented in Gadgeel, et al. WCLC 2016 (Abs PL04a.02)1. Williams et al. ESMO 2016 (1171P)
2. Barlesi, et al. ESMO 2016 (Abs LBA44)
Blood based PD‐L1
• PD‐L1 expression on CTCs
Complexity of the immune response
Mellman Nature 2012
Immune monitoring needs to be comprehensive‐immunogram
Blank, Science 2016; Yuan et al. JITC 2016
Conclusions
• PD‐L1 immunohistochemical expression – When high predicts for benefit– When negative does not exclude potential benefit
• Training and validation of PD‐L1 is required for proper assessment
• Cytological samples seem adequate for testing• Heterogeneity and dynamics might play a role• It needs to be combined to other markers for optimal patient selection
Gracias