Trial results for a study investigating atezolizumab plus tiragolumab, carboplatin, and etoposide in participants with untreated extensive-stage small cell lung cancer were posted on ClinicalTrials.gov on 2025-10-29. The combination therapy demonstrated an improved investigator-assessed objective response rate (ORR) of 81.5% compared to 58.9% for the control group, and a hazard ratio of 0.65 for progression-free survival.
Background
The study, titled "Study of Atezolizumab Plus Carboplatin and Etoposide With or Without Tiragolumab in Participants With Untreated Extensive-Stage Small Cell Lung Cancer," aimed to evaluate the safety and efficacy of adding tiragolumab to a regimen of atezolizumab, carboplatin, and etoposide for patients with untreated extensive-stage small cell lung cancer.
Trial design
The study (NCT04665856) was a Phase 3, multicenter trial conducted in China, enrolling 123 participants with untreated extensive-stage small cell lung cancer. Participants were randomized to receive either tiragolumab plus atezolizumab, carboplatin, and etoposide, or placebo plus atezolizumab, carboplatin, and etoposide. The trial evaluated the safety and efficacy of the additional tiragolumab.
Key results
The trial results demonstrated improvements in several key efficacy outcomes:
- Investigator-Assessed Progression-Free Survival (PFS): The median PFS was 5.59 months for the tiragolumab combination arm, compared to 5.39 months for the placebo combination arm. This translated to a Hazard Ratio (HR) of 0.65 (95.0% Confidence Interval: 0.43 to 0.97), with a p-value of 0.0348.
- Overall Survival (OS): The median OS for the tiragolumab combination arm was 18.69 months, versus 13.54 months for the placebo combination arm. The analysis showed an HR of 0.89 (95.0% Confidence Interval: 0.56 to 1.4), with a p-value of 0.6105.
- Investigator-Assessed Confirmed Objective Response Rate (ORR): The ORR was 81.5% in the tiragolumab combination arm, significantly higher than 58.9% in the placebo combination arm. The difference in ORR was 22.55% (95.0% Confidence Interval: 4.12 to 39.03), with a p-value of 0.0136.
What this means
The findings suggest that adding tiragolumab to the atezolizumab, carboplatin, and etoposide regimen may offer clinical benefits for patients with untreated extensive-stage small cell lung cancer. The statistically significant improvement in objective response rate and progression-free survival indicates enhanced tumor control with the addition of tiragolumab. While overall survival showed a numerical increase, it did not reach statistical significance in this analysis. These results provide important data for further evaluation of combination immunotherapies in this challenging cancer type.
Source
The information for these trial results was sourced from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04665856, titled "Study of Atezolizumab Plus Carboplatin and Etoposide With or Without Tiragolumab in Participants With Untreated Extensive-Stage Small Cell Lung Cancer," were posted on 2025-10-29 on clinicaltrials.gov.