The phase 3 IMforte study evaluated the efficacy and safety of first-line maintenance treatment with lurbinectedin combined with atezolizumab versus atezolizumab alone in patients with extensive-stage small cell lung cancer (ES-SCLC). Following standard induction therapy with atezolizumab, carboplatin, and etoposide, patients without disease progression were randomized to receive maintenance treatment. The study’s primary endpoints were independent review facility–assessed progression-free survival (IRF-PFS) and overall survival (OS). Secondary endpoints included investigator-assessed PFS, overall response rate, duration of response, and safety.1
Lurbinectedin plus atezolizumab significantly improved IRF-PFS compared with atezolizumab alone (hazard ratio [HR], 0.54; 95% confidence interval [CI], 0.43-0.67; P<.0001). A significant OS benefit was observed with lurbinectedin plus atezolizumab (HR, 0.73; 95% CI, 0.57-0.95; P=.0174). Median maintenance treatment durations were 4.1 months for lurbinectedin and 4.2 months for atezolizumab in the combination arm versus 2.1 months in the atezolizumab-alone arm.
Treatment-related adverse events (TRAEs) occurred more frequently in the lurbinectedin plus atezolizumab arm (83.5%) compared with atezolizumab alone (40.0%). Grade 3/4 TRAEs were reported in 25.6% of patients treated with lurbinectedin plus atezolizumab versus in 5.8% of patients who received atezolizumab alone, and grade 5 TRAEs were infrequent (0.8% vs 0.4%). No new or unexpected safety signals were identified.
IMforte is the first global phase 3 study to demonstrate survival benefits with first-line maintenance therapy for ES-SCLC.
Source
- Paz-Ares L, Borghaei H, Liu SV, et al. Lurbinectedin (lurbi) + atezolizumab (atezo) as first-line (1L) maintenance treatment (tx) in patients (pts) with extensive-stage small cell lung cancer (ES-SCLC): primary results of the phase 3 IMforte trial. Presented at: 2025 ASCO Annual Meeting. May 30-June 3, 2025; Chicago, IL. Abstract 8006.