Introduction of checkpoint inhibitors (anti PD-1/PD-L1) have resulted in improved survival for bladder cancer patients, however, only a subset will benefit. The utility of PD-L1 expression as a prognostic or predictive biomarker is limited, motivating the search for more robust biomarkers. Here, we examined the prognostic value of densities of PD-L1, CD3, CD8 or CD68 positive cells and studied the reproducibility of the findings across two patient cohorts in a multi-assay and multicentre setting.
MIBC specimens (T stage 2/3) from two patient cohorts collected at Melbourne, Australia (n = 39) and University of St Andrews, UK (n = 63) were studied. Two consecutive slides were stained with a brightfield immunohistochemistry or an immunofluorescence assay in the first and second cohorts, respectively. The densities of positive cells within the tumour core were determined using assay-specific image analysis algorithms. Within each cohort, the prognostic value of each cell density was assessed using univariate and multivariate Cox regression including age, T stage, N stage and adjuvant chemotherapy as covariates.
The Melbourne cohort is slightly older, with a poorer prognosis and a higher proportion of N2/N3 disease compared to the St Andrews cohort. Univariate and multivariate analyses identified the density of CD8 positive cells as an important prognostic factor across both cohorts (p < 0.05). PD-L1 is significant in the St Andrews cohort and trends towards significance (p < 0.1) in the Melbourne cohort, whilst the reverse is seen with CD3. The significance level of CD68 cannot be reproduced across cohorts. Cohort statistics, hazard ratios and p values from univariate and multivariate survival analysis. .p < 0.1, *p<0.05, **p<0.01Cohort 1: Melbourne Cohort 2: St Andrews Median age 71.64 66 Median survival time (months) 23.7 - Overall 32.57 - Disease Related T stage T2 16 (41%) 26 (41%) T3 23 (59%) 37 (59%) N stage N1 3 (8%) 52 (88%) N2 8 (20%) 7 (11%) N3 28 (72%) 0 (0%) Univariate Cox regression CD8 HR 0.93 (0.88 0.98), p = 0.007 ** HR 0.90 (0.83 0.97), p = 0.005 ** PD-L1 HR 0.97 (0.94 1.00), p = 0.065 . HR 0.86 (0.75 0.98), p = 0.023 * CD3 HR 0.92 (0.87 0.97), p = 0.003 ** HR 0.92 (0.87 0.98), p = 0.010 * CD68 HR 0.93 (0.88 0.99), p = 0.025 * HR 0.97 (0.93 1.00), p = 0.088 . Multivariate Cox regression CD8 HR 0.92 (0.88 0.97), p = 0.003 ** HR 0.92 (0.86 0.99), p = 0.029 * PD-L1 HR 0.96 (0.92 1.00), p = 0.053 . HR 0.84 (0.74 0.97), p = 0.015 * CD3 HR 0.90 (0.85 0.95), p = 0.0004** HR 0.94 (0.88 1.00), p = 0.060 . CD68 HR 0.92 (0.86 0.99), p = 0.023 * HR 0.98 (0.94 1.02), p = 0.294
Our multicentre and multi-assay study suggests that the density of CD8 positive cells in the tumour core is a robust prognostic factor in MIBC. Further investigation of PD-L1 and CD3 cell density is warranted.
Definiens AG; The Walter and Eliza Hall Institute of Medical Research; University of St Andrews.
Definiens AG.
K. Nekolla: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. N. Brieu: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. C.G. Gavriel: Research grant / Funding (self), Definiens is a full subsidiary of AstraZeneca: Definiens AG. M. Widmaier: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. A. Budco: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. D. Medrikova: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. I. Kanchev: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. M. Testori: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. J. Chan: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. D.J. Harrison: Advisory / Consultancy, Member: Scientific Advisory Board: Definiens AG; Full / Part-time employment: NuCana plc; Leadership role, Director: Industrial Centre for AI Research in Digital Diagnostics. M. Baehner: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG. P.D. Caie: Research grant / Funding (institution): Definiens AG. B. Tran: Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self), Research grant / Funding (institution), Travel / Accommodation / Expenses: Amgen; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self), Travel / Accommodation / Expenses: Astellas; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self), Travel / Accommodation / Expenses: Bayer; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self): BMS; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self), Research grant / Funding (institution), Non-remunerated activity/ies: Janssen-Cilag; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): MSD; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Novartis; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Sanofi; Honoraria (self), Advisory / Consultancy: Tolmar; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Ipsen; Research grant / Funding (self), Research grant / Funding (institution): AstraZeneca; Research grant / Funding (self): Pfizer; Research grant / Funding (self), Research grant / Funding (institution): Servier; Research grant / Funding (institution): Aslan; Research grant / Funding (institution): GSK; Research grant / Funding (institution): Taiho; Research grant / Funding (institution): Akeso; Research grant / Funding (institution): MedImmune; Research grant / Funding (institution): Aptevo; Leadership role, Chair - GU Tumour Group: Cancer Trials Australia; Leadership role, Chair - Germ Cell Tumour Subcommittee, Member - Scientific Advisory Committee: ANZUP; Leadership role, Member - Scientific Advisory Committee: Biogrid; Leadership role, Member - Scientific Advisory Committee: Parkville Cancer Clinical Trials Unit; Leadership role, Co-Chair - Molecular Tumour Board: Victorian Comprehensive Cancer Centre. G. Schmidt: Full / Part-time employment, Definiens is a full subsidiary of AstraZeneca: Definiens AG; Shareholder / Stockholder / Stock options: AstraZeneca; Licensing / Royalties, Royalities "Tissue Phenomics" ISBN 9789814774888: Pan Stanford Publishing. All other authors have declared no conflicts of interest.