949P Impact of antibiotic use and derived neutrophil to lymphocyte ratio (dNLR) in patients with recurrent/metastatic head and neck squamous cell cancer (R/M HNSCC) treated with immunotherapy

Abstract

Antibiotic (atx) use and dNLR (neutrophils/(leukocytes−neutrophils)) (dNLR) have been associated with worse outcome in patients (pts) treated with antiPD-1/PD-L1 agents across many tumor types. We investigated the prognostic value of these biomarkers in a cohort of R/M HNSCC pts treated with immunotherapy (IT). Retrospective single institution analysis of R/M HNSCC pts treated with antiPD-1/PD-L1 alone or in combination with other IT or chemotherapy (CT) between 2015 and 2019. Data on atx use (30 days pre- up to 30 days post-IT start), clinical and baseline routine blood parameters, and objective response rate (ORR) by RECIST 1.1 were collected. Kaplan-Meier for overall survival (OS) and progression-free survival (PFS) were estimated and compared by log-rank test between atx (yes/no) and dNLR (>3/≤3). Multivariate analysis (MVA) were performed and hazard ratios (HR) and 95% confidence interval (IC) were reported. A total of 74 pts were evaluated: median age 58 years (range 51-64); 82.4% men. Recurrence site: locoregional/distant/both=45.9%/12.2%/41.9%; PD-L1>1%=32.4%; number of prior lines in R/M 0/≥1= 32.9%/67.1%. Treatment: antiPD-1/PD-L1 alone=44.6%, combo IT=51.4% and IT+ CT=4.1%; atx use 31,1%; dNLR ≤3/>3=66.2%/33.8%. Best ORR by atx use yes/no (%): complete response 13.6/0, partial response 18.2/17.7, stable disease 27.3/15.7, progression 40.9/66.7 (p=0.025). Median follow-up = 8.4 months (m) (range 3.5-19.4). Median OS and PFS did not differ by atx use yes vs no (4.8m vs 10.1m; p=0.71 and 2.1m vs 2.5m, p=0.43 respectively). OS and PFS were significantly higher in pts with baseline dNLR ≤3 vs >3 (11.4m vs 4.8m, p=0.013 and 2.5m vs 1.7m; p=0.038). In the MVA including atx, PD-L1 status, number of prior lines and site of recurrence, only dNLR> 3 was associated with both progression and death (HR 2.0; 95%CI: 1.1-3.7; p=0.024 for both). Atx use in R/M HNSCC pts had a favourable impact on response rate, but not on OS and PFS in our cohort. After adjusting by atx use, baseline dNLR>3 remains strongly associated with worse OS and PFS. Derived NLR could be an easily-accessible tool to identify R/M HNSCC pts who benefit from IT treatment.