Background: The therapeutic efficacy of cytotoxic anticancer drugs has been reported to be enhanced after immune checkpoint inhibitors (ICI) in non-small cell lung cancer; however, it is unclear whether the same is applicable for small cell lung cancer (SCLC). We evaluated the efficacy of second-line amrubicin (AMR) following first-line platinum-based chemotherapy and ICI combination therapy (chemo-ICI) in SCLC.
Patients and methods: We retrospectively enrolled consecutive patients with SCLC treated with AMR as a second-line following chemo-ICI as first-line between July 2019 and April 2021 from 16 institutions throughout Japan. We investigated the therapeutic effectiveness, safety, and efficacy-enhancing variables of AMR.
Results: Overall, 89 patients treated with AMR after first-line chemo-ICI were analyzed. The overall response rate (ORR) was 29.2% (95% confidence intervals [CI], 20.1-39.8) and median PFS (m PFS) was 2.99 months (95% CI, 2.27-3.65). Patients who relapsed more than 90 days after receiving first-line platinum combination therapy (sensitive relapse) exhibited greater ORR (58.3% vs. 24.7%, p = 0.035) and m PFS (5.03 vs. 2.56 months, p = 0.019) than patients who relapsed in <90 days (refractory relapse). Grade 3 or higher adverse events were mainly hematological toxicity.
Conclusions: Our study suggested that the therapeutic effect of AMR was not enhanced after ICI on SCLC. However, AMR may be effective in cases of sensitive relapse after chemo-ICI. There was no increase in severe toxicity associated with AMR after ICI.
Keywords: amrubicin; atezolizumab; durvalumab; immune checkpoint inhibitor; small cell lung cancer.
© 2022 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.