A prognostic score for patients with malignant pleural mesothelioma (MPM) receiving second-line immunotherapy or chemotherapy in the ETOP 9-15 PROMISE-meso phase III trial.

INTRODUCTION

Clinical and laboratory parameters associated with response for patients with advanced pre-treated malignant pleural mesothelioma (MPM) are lacking. We aimed to identify prognostic and predictive markers among patients with relapsed MPM who were randomised into the ETOP 9-15 PROMISE-meso phase III trial, evaluating pembrolizumab and chemotherapy.

METHODS

Baseline clinical and laboratory parameters were investigated for prognostic or predictive value on progression-free survival (PFS) and overall survival (OS) in a retrospective analysis, based on the full cohort of 144 MPM patients. These consisted of immune-inflammatory indexes (neutrophil-lymphocyte ratio [NLR], systemic immune-inflammatory index [SII], lactate dehydrogenase [LDH]) along with other already known prognostic baseline characteristics and laboratory values. Cut-offs were chosen independently of outcome. Based on Cox multivariable analysis for PFS in the whole cohort, a risk factor model was built to illustrate the prognostic stratification of patients by the combination of the derived independent prognostic factors, taking into account the EORTC score, a validated prognostic score in MPM. All models were stratified by histology and adjusted by treatment.

RESULTS

In the stratified multivariable analysis in the whole cohort, high SII (hazard ratio (HR) 2.06; 95%CI 1.39-3.05) and low haemoglobin (HR 1.62; 95%CI 1.06-2.50) were associated with worse PFS. Based on these two prognostic factors, a mesothelioma risk score (MRS) was constructed with three PFS risk prognosis categories: favourable, intermediate and poor with 0, 1 and 2 risk factors, respectively (corresponding percent of cohort: 24%, 34% and 42% and median PFS: 5.8, 4.2 and 2.1 months). The derived MRS stratified the prognosis for PFS and OS, overall and within each of the EORTC groups. No significant predictors of treatment benefit were identified.

CONCLUSIONS

The proposed MRS is prognostic of patient outcome and it fine-tunes the prognosis of patients with pre-treated MPM alone or when used with the already established EORTC score.