The addition of immunotherapy (either atezolizumab or durvalumab) to platinum-etoposide for patients with extensive stage SCLC (ES-SCLC) has been recently established as standard first-line treatment based on IMPOWER133 and CASPIAN trials. Yet, the efficacy and safety in a real-world setting remains unclear.
We retrospectively evaluated patients with ES-SCLC treated with either atezolizumab or durvalumab plus platinum-etoposide between October 2018 and October 2021 in ten centres in the UK and ten centres in Switzerland. Responses were assessed using RECIST v1.1 criteria. Median PFS and OS were analyzed by the Kaplan-Meier method.
A total of 436 patients were included. Median age was 67 years, 228 (52.3%) were males, 209 patients (47.9%) were current and 203 (46.6%) former smokers. 63 patients (14.4%) had an ECOG performance status (PS) ≥2. 385 patients (88.3%) were initially diagnosed with ES-SCLC. Liver and brain metastases were diagnosed in 170 (39.0%) and 87 (20.0%) of patients, respectively. At the time of analysis, 284 patients (65.1%) had died. Most of the patients received atezolizumab (n=427, 97.9%) in combination with chemotherapy, 2.1% received durvalumab. Most patients (n=422, 96.8%) were treated with carboplatin/etoposide. Overall response rate was 71.8% (95%CI 67.3-76.0%) with a median duration of response of 3.5 months (95%CI 3.3-4.0). Median PFS and OS were 5.5 (95%CI 5.3-5.7) and 9.3 months (95%CI 8.4-10.4), respectively. Immune related adverse events (AEs) were seen in 21.8% of patients. 5 patients (1.1%) developed a grade 5 AE. 174 patients (39.9%) received a subsequent systemic therapy. Among patients with brain metastases at diagnosis, mPFS and mOS were 4.8 months (95%CI 4.4-5.5) and 8.6 (95%CI 6.9-10.8), respectively.
Data from our large series show shorter OS than what reported in the trials. Known poor prognostic factors (mainly ECOG PS ≥2 and brain metastases) were more common in our cohort of patients at baseline and may have determined a shorter OS. This is the largest real-world evidence dataset evaluating patients with ES-SCLC treated with first-line chemo-immunotherapy, and could help to optimise clinical management of these patients.
The authors.
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All authors have declared no conflicts of interest.