Abstract 71P
Background
Chemotherapy (CT) combined with anti-PD-L1 immunotherapy (IO) is now standard first-line setting for patients with extensive SCLC. However, no reliable biomarker can predict which patients will benefit the most from this association. Imaging Mass Cytometry (IMC) Hyperion® (Fluidigm) is a new multiplex strategy allowing the characterization of different cell populations in tumor microenvironment (TME) and could highlight strong biomarkers.
Methods
HYPE is a single-center retrospective cohort study conducted in France between June 2019 and February 2021. All advanced SCLC patients treated with first-line atezolizumab combined with platinum-etoposide regimen were eligible. Baseline available tumor samples were analyzed using a panel of 40 relevant metal-tagged antibodies in IMC. Primary objective was the determination of immunophenotypic traits correlated with progression-free survival (PFS). Reported outcomes were PFS, overall survival (OS), overall response rate (ORR) and safety.
Results
Twenty patients were included. After a median follow-up of 9,5 months, median PFS and OS in the overall population reached 5 months [95% CI 3,0-7,0] and 9 months [95% CI 8,0-19,0], respectively. ORR was 85%. Median duration of response was 4 months [95% CI 3,0-6,0]. Safety was consistent with previously reported safety profiles. TME comparison of 11 available tumor samples was performed using IMC. Higher percentage of CD4+, CD8+, and regulatory T cells in the TME was significantly correlated with a longer PFS (p=0,001, p=0,025 and p=0,002 respectively). Higher expression of granzyme B was also significantly correlated with a longer PFS (p=0,029). No significant correlation was found with natural killer cells, B cells or granulocytes. PD-L1, TIM-3 and LAG-3 checkpoints were not correlated with improved PFS either.
Conclusions
Despite our small number of patients, immunophenotypic traits are emerging from TME using IMC technology but would deserve further investigations in a larger cohort. Efficacy and tolerance of CT-IO combination in advanced SCLC were consistent with previous clinical trials.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Roche, BMS.
Disclosure
All authors have declared no conflicts of interest.