Trial results for a Phase III study (NCT05091567) investigating atezolizumab in combination with lurbinectedin as maintenance therapy for extensive-stage small-cell lung cancer (ES-SCLC) were posted on ClinicalTrials.gov on 2025-12-29. The combination therapy demonstrated an improvement in median progression-free survival (PFS) to 5.36 months compared to 2.14 months for atezolizumab alone, and median overall survival (OS) to 13.24 months compared to 10.64 months.
Background
Atezolizumab is an immunotherapy agent used in various cancers, including small-cell lung cancer. This study specifically evaluated its role as maintenance therapy for participants with extensive-stage small-cell lung cancer (ES-SCLC) who had achieved an ongoing response or stable disease after initial treatment with carboplatin, etoposide, and atezolizumab. The trial aimed to assess the benefit of adding lurbinectedin to atezolizumab in this maintenance setting.
Trial design
The Phase III, open-label, multicenter study (NCT05091567) enrolled 660 participants with extensive-stage Small-Cell Lung Cancer. Participants had completed 4 cycles of first-line induction therapy with carboplatin, etoposide, and atezolizumab, and had an ongoing response or stable disease. The study consisted of an induction phase and a randomized maintenance phase. In the maintenance phase, participants were randomized to receive either atezolizumab alone or atezolizumab in combination with lurbinectedin.
Key results
Key efficacy outcomes from the randomized phase, as assessed by an Independent Review Facility (IRF) and investigators, included progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and duration of response (DOR).
- IRF-Assessed Progression-Free Survival (PFS): The median PFS was 5.36 months (95% Confidence Interval: 4.24 months) for the Atezolizumab + Lurbinectedin group, compared to 2.14 months (95% Confidence Interval: 1.64 months) for the Atezolizumab group. The stratified analysis showed a Hazard Ratio (HR) of 0.54 (95% CI: 0.43-0.67) with a p-value of 0.0001.
- Overall Survival (OS): The median OS was 13.24 months (95% Confidence Interval: 11.89 months) for the Atezolizumab + Lurbinectedin group, versus 10.64 months (95% Confidence Interval: 9.49 months) for the Atezolizumab group. The stratified analysis yielded an HR of 0.73 (95% CI: 0.57-0.95) with a p-value of 0.0174.
- Investigator-Assessed PFS: Median PFS was 5.36 months (95% Confidence Interval: 4.30 months) for the combination group and 2.73 months (95% Confidence Interval: 2.53 months) for the Atezolizumab group. The Hazard Ratio was 0.55 (95% CI: 0.45-0.68).
- IRF-Assessed Objective Response Rate (ORR): The ORR was 19.4 percentage of participants (95% Confidence Interval: 13.85 percentage of participants) for the combination group, compared to 10.4 percentage of participants (95% Confidence Interval: 6.40 percentage of participants) for the Atezolizumab group. The difference in ORR was 8.99 (95% CI: 1.07-16.9).
- IRF-Assessed Duration of Response (DOR): Median DOR was 9.00 months for the Atezolizumab + Lurbinectedin group, versus 5.62 months for the Atezolizumab group.
What this means
The results suggest that adding lurbinectedin to atezolizumab as maintenance therapy significantly improves key efficacy endpoints in patients with extensive-stage small-cell lung cancer who have responded to initial induction therapy. The observed improvements in median PFS and OS, along with a statistically significant hazard ratio for both outcomes, indicate a clinical benefit for the combination regimen. The higher objective response rate and longer duration of response also support the potential of this combination to provide more sustained disease control for this patient population.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT05091567, titled "A Phase III, Open-Label Study of Maintenance Lurbinectedin in Combination With Atezolizumab Compared With Atezolizumab in Participants With Extensive-Stage Small-Cell Lung Cancer," were posted on 2025-12-29 on clinicaltrials.gov.