Abstract
BACKGROUND: Immune checkpoint inhibitors (ICIs) offer durable progression-free survival (PFS) benefit in a subset of patients with advanced non-small cell lung cancer (NSCLC). However, the predictors of long-term PFS (LTPFS) remain unclear. METHODS: Advanced NSCLC patients receiving first-line ICIs monotherapy at Guangdong Lung Cancer Institute between December 2017 and August 2022 were identified. Predictive value of different characteristics was evaluated in LTPFS (PFS ≥ 24 months) compared with short-term PFS (STPFS, PFS ≤ 3 months). Circulating cytokine levels were evaluated in paired peripheral blood samples collected before and after ICIs treatment. RESULTS: Among 202 patients identified and 171 included (median follow-up: 41.0 months), 44 (25.7%) experienced LTPFS, associated with a 5-year overall survival (OS) rate of 81.2%. Squamous NSCLC, intermediate or poor lung immune prognostic index (LIPI) score, and liver metastases, were negatively associated with LTPFS. High tumor mutational burden (TMB, ≥ 10 mutations/megabase) was enriched in LTPFS compared to STPFS (P = 0.002). Patients with both high TMB and PD-L1 demonstrated the greatest survival benefit from first-line ICIs monotherapy (median PFS: 24.5 months, median OS: 67.0 months). Thirty-eight peripheral blood samples were collected before and after ICIs treatment from 10 patients with LTPFS and 9 with STPFS, which revealed increased CCL11 (P = 0.013) and decreased IL1RA (P = 0.001) and IL17A (P = 0.003) levels in LTPFS after ICIs treatment. CONCLUSION: Distinct clinical characteristics, including TMB, PD-L1, pathologic subtypes, LIPI score, number of organs involved, metastatic sites, and dynamic circulating cytokines profile features, can distinguish NSCLC patients achieving LTPFS from those with STPFS following first-line ICIs monotherapy.