Key Clinical Summary: 

• Design/Population: This post hoc analysis of the phase 3 IMforte trial evaluated patterns of subsequent therapy in patients with ES-SCLC treated with lurbinectedin plus atezolizumab or atezolizumab alone after induction chemoimmunotherapy.
• Key Outcomes: The combination delayed initiation of second-line therapy and maintained an overall survival benefit compared with atezolizumab alone. Second-line lurbinectedin was associated with improved outcomes compared with other therapies.
• Clinical Relevance: These findings support the use of lurbinectedin in the first line setting to improve survival and optimize treatment sequencing in ES-SCLC. Early integration of lurbinectedin may enhance outcomes across multiple lines of therapy.

Exploratory results from the phase 3 IMforte trial suggest that first-line treatment with lurbinectedin plus atezolizumab delays subsequent therapy and maintains overall survival (OS) benefit compared with atezolizumab alone in patients with extensive-stage small cell lung cancer (ES-SCLC).

These results were presented at the 2026 European Lung Cancer Congress in Copenhagen, Denmark, by Yuabin Chen, MD, The Cancers and Hematology Centers, Grand Rapids, Michigan.

In this study, 483 patients who did not experience disease progression after induction therapy with atezolizumab, carboplatin, and etoposide were randomized 1:1 to receive 1200 mg of atezolizumab (n = 241) either alone or in combination with 3.2 mg/m² of lurbinectedin (n = 242) until disease progression or unacceptable toxicity. Patients were permitted to undergo subsequent therapy at the discretion of treating physicians.

At analysis, 45% of patients in the lurbinectedin plus atezolizumab arm and 55% of patients in the atezolizumab arm received second-line therapy. The most prescribed second-line treatment was platinum-based chemotherapy. The median time from randomization to initiation of second-line therapy was 4.8 months in the lurbinectedin plus atezolizumab arm and 3.5 months in the atezolizumab arm. Median duration of second-line therapy was 2.2 months and 2.3 months, respectively.

In the atezolizumab arm, median duration of second-line treatment was 3.7 months in patients who received lurbinectedin (n = 17) and 2.2 months in patients who received other therapies (n = 115). Median OS from the start of second-line therapy was 9.9 months and 6.9 months, respectively. The OS benefit of lurbinectedin plus atezolizumab over atezolizumab alone was maintained when adjusted for potential survival bias introduced by second-line lurbinectedin use (hazard ratio, 0.68).

“This exploratory analysis shows that the addition of [lurbinectedin to atezolizumab] in 1Lm [treatment] can improve pt survival, delay time to 2L [treatment], and allow for the use of emerging 2L [treatment],” concluded Dr Chen et al. “when used as 2L [treatment, lurbinectedin] was associated with improved survival compared with other 2L [treatment].”

Source: 

Chen Y, Paz-Ares L, Borghaei H, et al. IMforte: Subsequent treatment (Tx) following first-line maintenance (1Lm) with lurbinectedin (lurbi) + atezolizumab (atezo) or atezo in extensive stage small cell lung cancer (ES-SCLC). Presented at European Lung Cancer Congress. March 25 - 28, 2026. Copenhagen, Denmark. 423P.