Abstract 1318P
Background
Immune checkpoints inhibitors (ICIs) have revolutionized the treatment of advanced non-small cell lung cancer (NSCLC). PD-L1 expression on tumor specimens is the only approved predictive biomarker (tissue PD-L1, tPD-L1). However, the outcome of patients treated with ICIs is frequently independent from tPD-L1 status; thus, more suitable biomarkers are needed. In this study, we analyzed the role of soluble PD-L1 (sPD-L1) collected from the peripheral blood of patients with advanced NSCLC treated with nivolumab (Nivo) or pembrolizumab (Pembro).
Methods
We evaluated sPD-L1 in baseline plasma samples withdrawn from 196 advanced NSCLC patients, including 118 patients treated with Nivo in second or further lines (range: 1-6 previous lines), 56 patients with high tissue PD-L1 expression (tPD-L1≥50%) treated with Pembro in first line, and 22 patients with low tissue PD-L1 expression (tPD-L1 <50%) treated with chemotherapy (Chemo); additionally, we evaluated sPD-L1 from 88 healthy donors. sPD-L1 was analyzed with enzyme linked immunosorbent assay (ELISA), by using Dako PD-L1 28-8 pharmDx assay. We explored correlations between sPD-L1 and clinical outcomes of Pembro cohort and Nivo cohort. In addition, we compared sPD-L1 with tPD-L1 in previously untreated patients (Pembro cohort and Chemo cohort).
Results
The sPD-L1 median concentration of 23.92 pg/ml was used as cut- off. sPD-L1 level was higher in patients with advanced NSCLC compared to healthy controls (p<0.0001). Moreover, we found higher concentration of sPD-L1 in previously untreated patients with tPD-L1≥50% versus patients with tPD-L1<50% (p= 0.033). In Pembro cohort, median overall survival in low and high sPD-L1 level groups were 16.0 and 10.9 months, respectively (p=0.045). No difference in progression-free survival or objective response was observed. In Nivo cohort, sPD-L1 was not associated with clinical outcomes.
Conclusions
Our study shows that baseline sPD-L1 is associated with poor prognosis in advanced NSCLC patients treated with Pembro in first line. sPD-L1 was not prognostic for pre-treated patients receiving Nivo. Additional analyses on longitudinal sPD-L1 assessments are ongoing.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Lung Cancer Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
Funding
Has not received any funding.
Disclosure
C. Dellepiane: Honoraria (self): BMS; Travel/Accommodation/Expenses: Roche; Travel/Accommodation/Expenses: MSD. G. Rossi, E. Rijavec, F. Biello, M. Tagliamento, E. Bennicelli, F. Grossi, P. Pronzato: Honoraria (self): MSD; Honoraria (self): BMS. L. Zullo: Honoraria (self): BMS; Travel/Accommodation/Expenses: MSD. C. Genova: Honoraria (self): AstraZeneca; Honoraria (self): BMS; Honoraria (self): MSD; Honoraria (self): roche; Honoraria (self): Boehringer Ingelheim. All other authors have declared no conflicts of interest.