Atezolizumab Plus Carboplatin and Etoposide in Patients with Untreated Extensive-Stage Small-Cell Lung Cancer: Interim Results of the MAURIS Phase IIIb Trial

Background: MAURIS is an Italian multicenter, open-label, phase IIIb ongoing trial, aiming at evaluating the safety and effectiveness of atezolizumab+carboplatin/etoposide in patients with newly diagnosed, extensive-stage small-cell lung cancer (ES-SCLC). The primary objective is the safety evaluation. Materials and Methods: Patients received atezolizumab+carboplatin/etoposide Q3W for 4-6 cycles in the induction phase, followed by atezolizumab maintenance Q3W. We presented the interim analysis on safety (referring to the induction phase) and clinical effectiveness, in all patients (N=154) and in subgroups that received ≤3 (N=23), 4 (N=43), and 5-6 cycles (N=89) of induction. Results: At a median follow-up of 10.5 months, 139 patients (90.3%) discontinued treatment. Serious adverse events occurred in 29.9% of patients overall, and the rate was lower in patients with 5-6 cycles (19.1%) than in those with 4 (34.9%) or ≤3 (63.6%) cycles. Immune-mediated adverse events were reported in 14.9%, 15.7%, 11.6%, and 18.2% of patients, overall and by subgroup, respectively. The median overall survival and progression-free survival were 10.7 and 5.5 months, respectively. Overall, 111 patients (71.6%) had a tumor response. Conclusions: Interim results provide further evidences about safety and efficacy profile of atezolizumab+carboplatin/etoposide treatment in a ES-SCLC patient population closer to that observed in clinical practice. Clinical Trial Registration: Eudract No. 2019-001146-17, NCT04028050.