58P - PDL1 expression associated with worse survival outcome in malignant pleural mesothelioma

Date 17 December 2016
Event ESMO Asia 2016 Congress
Session Poster lunch
Topics Mesothelioma
Translational Research
Presenter Bella Nguyen
Citation Annals of Oncology (2016) 27 (suppl_9): ix9-ix18. 10.1093/annonc/mdw574
Authors B. Nguyen1, R. Montgomery2, M. Fadia2, J. Wang3, S. Ali1
  • 1Department Of Medical Oncology, The Canberra Hospital, 2606 - Canberra/AU
  • 2Department Of Anatomical Pathology, The Canberra Hospital, 2606 - Canberra/AU
  • 3Statistical Consulting Unit, The Australian National University, 2601 - Canberra/AU

Abstract

Background

There is currently a need to identify an effective prognostic biomarker to assist in a risk adopted approach in treatment of malignant pleural mesothelioma (MPM). Expression of programmed cell death receptor ligand (PDL1) has been studied as a prognostic and predictive biomarker in a number of tumours given its central role in anti tumoural immune response evasion. Immunotherapy targeting PD1 have also been shown to be promising in MPM. Three recent published analysis found PDL1 positivity to be an adverse prognostic factor for survival. This study aims to investigate the relationship between PDL1 expression in mesothelioma tissues and survival outcome.

Methods

Fifty-three patients from a single institution diagnosed with MPM based on histopathology from 01/2006 to 12/2015 were reviewed. Formalin fixed, paraffin embedded tissue were stained with PDL1 (Clone Ventana SP263). PDL1 positivity was defined as > 1% membranous staining regardless of intensity, moderately positive was defined as 1-10% and highly positive was defined as ≥ 10%. R Statistical Analysis Package was used for analysis.

Results

Fifty-three patients had available histopathology and data for analysis. Median age was 73, majority was male (46, 87%). Forty-one (77%) had ECOG between 0-2, and 12 had ECOG of 3 (22%). Thirty-six (68%) had epitheliod subtype, 7 (13%) sarcomatoid subtype, and 10 (19%) biphasic subtype. Thirty patients received best supportive care, 15 patients received chemotherapy and 8 patients received a combination of chemotherapy and radiotherapy. Fourteen (26.41%) patients were PDL1 negative, 17 (32.08%) moderate positive and 22 (41.51%) highly positive. PDL1 as a prognostic marker was independently associated with adverse outcome. Highly positive PDL1 expression correlated with worse prognosis (HR = 2.38, 95%, CI = 1.01,5.6, p-value=0.046). Median survival of PDL1 negative, and highly positive was 13 months and 5.5 months respectively. On multivariate analysis PDL1, ECOG>2 and histology subtypes were found to be independently associated with adverse outcome.

Conclusions

Our analysis found a higher percentage of MPM patients with positive PDL1 (>1%) compared to other studies. Highly positive PDL1 expression was associated with significantly lower median survival time.

Clinical trial indentification

Legal entity responsible for the study

The Canberra Hospital

Funding

The Canberra Hospital Private Fund Practice

Disclosure

B. Nguyen: Recipient of the Canberra Private Fund Practice. S. Ali: Medical Advisory board: Nivolumab and Pembrolizumab; Conference sponsorships, speaker fees Recipient of the Canberra Private Fund Practice. All other authors have declared no conflicts of interest.