IMforte Study Design and Maintenance Approach in ES-SCLC

Isabel Preeshagul, DO, MBS Memorial Sloan Kettering Cancer Center | Rahul Gosain, MD, MBA Wilmot Cancer Institute | Rohit Gosain, MD Roswell Park Comprehensive Cancer Center

October 10, 2025

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Key Points

  • Lurbinectedin plus atezolizumab was approved as a first-line maintenance regimen for patients with extensive-stage small cell lung cancer (ES-SCLC) based on the phase 3 IMforte trial.

  • IMforte showed that the addition of lurbinectedin to atezolizumab in maintenance improved overall survival (OS) after induction.

  • Lurbinected plus atezolizumab maintenance is now the standard of care in patients with untreated ES-SCLC.

IMforte Trial: Lurbinectedin Plus Atezolizumab Maintenance Therapy

In a digital roundtable discussion for the Oncology Brothers podcast, cohosts Rahul Gosain, MD, MBA, of Wilmot Cancer Institute, and Rohit Gosain, MD, of Roswell Park Comprehensive Cancer Center, were joined by three thoracic oncologists to discuss the recent approval of lurbinectedin plus atezolizumab for first-line maintenance therapy in ES-SCLC based on the phase 3 IMforte trial. Isabel Preeshagul, DO, MBS, of Memorial Sloan Kettering Cancer Center, described the trial’s design and findings.

IMforte included treatment-naive patients with newly diagnosed ES-SCLC. Participants underwent four cycles of induction therapy with carboplatin, etoposide, and atezolizumab every 3 weeks. After induction, patients who achieved stable disease or better were randomized to maintenance therapy with lurbinectedin plus atezolizumab or atezolizumab alone every 3 weeks until progression or unmanageable toxicity.

The IMforte findings, first presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, showed that the combination maintenance regimen improved OS compared with atezolizumab monotherapy. Specifically, the lurbinectedin group had a median OS from randomization of 13.2 months compared with 10.6 months in the atezolizumab monotherapy group (stratified hazard ratio [HR], 0.73; 95% CI, 0.57–0.95; P = .017). 

This maintenance therapy approach expands the frontline approvals in ES-SCLC, which include carboplatin, etoposide, and atezolizumab based on the IMpower133 trial, and carboplatin, etoposide, and durvalumab based on the CASPIAN trial.