Identification of inflamed-phenotype of small cell lung cancer leading to the efficacy of anti-PD-L1 antibody and chemotherapy

Lung Cancer. 2023 May:179:107183. doi: 10.1016/j.lungcan.2023.107183. Epub 2023 Mar 25.

Abstract

Background: Platinum etoposide plus anti-programmed cell death ligand-1 (PD-L1) antibody therapy is the standard of care for extensive-stage small cell lung cancer (ES-SCLC). However, patient characteristics associated with the efficacy of the combination therapy in SCLC are unclear.

Methods: We retrospectively reviewed post-surgical limited-stage (LS)-SCLC and ES-SCLC patients treated with atezolizumab plus carboplatin and etoposide (ACE). The association between SCLC subtypes based on transcriptomic data and pathological findings, including CD8-positive tumor-infiltrating lymphocyte (TIL) status, was investigated in the LS-SCLC cohort. The association between the efficacy of ACE therapy, pathological subtypes, and TIL status was evaluated in the ES-SCLC cohort.

Results: The LS-SCLC cohort (N = 48) was classified into four SCLC subtypes (ASCL1 + NEUROD1 [SCLC-A + N, N = 17], POU2F3 [SCLC-P, N = 15], YAP1 [SCLC-Y, N = 10], and inflamed [SCLC-I, N = 6]) based on transcriptomic data. SCLC-I showed enriched immune-related pathways, the highest immune score (CD8A expression and T-cell-inflamed gene expression profiles), and epithelial-mesenchymal transition (EMT), in transcriptional subtypes. Immunohistochemical staining (IHC) showed that SCLC-I had the highest density of CD8-positive TILs in transcriptional subtypes. In the ES-SCLC cohort, the efficacy of ACE therapy did not differ according to pathological subtypes. The progression-free survival (PFS) of TILHigh patients was significantly longer than that of TILLow patients (PFS: 7.3 months vs. 4.0 months, p < 0.001).

Conclusion: Tumors with a high density of TILs, which represent the most immunogenic SCLC subtype (SCLC-I), based on transcriptomic data could benefit from ACE therapy.

Keywords: Platinum etoposide (ETP) plus programmed cell death ligand-1 (PD-L1) antibody therapy; SCLC subtypes; Small cell lung cancer (SCLC); Tumor-infiltrating lymphocyte (TIL).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Etoposide / therapeutic use
  • Humans
  • Lung Neoplasms* / drug therapy
  • Phenotype
  • Retrospective Studies
  • Small Cell Lung Carcinoma* / drug therapy

Substances

  • Etoposide