ClinicalTrials.gov recorded primary completion on 31 August 2023 for a multicenter Phase 3 study of atezolizumab in untreated extensive-stage small cell lung cancer. In the primary analysis set, adding tiragolumab to atezolizumab, carboplatin, and etoposide produced median overall survival of 18.69 months, compared with 13.54 months for placebo plus the atezolizumab regimen.

Background

The study evaluated atezolizumab with carboplatin and etoposide, with or without tiragolumab, in participants with untreated extensive-stage small cell lung cancer. The trial was conducted in China and compared tiragolumab plus atezolizumab and chemotherapy with placebo plus atezolizumab and chemotherapy. The supplied record does not provide mechanism details, prior approvals, or prevalence estimates.

Trial design

This Phase 3 study, identified as NCT04665856, enrolled 123 participants and is listed as completed. Its condition was small cell lung carcinoma. The interventions were tiragolumab, atezolizumab, carboplatin, etoposide, and tiragolumab matching placebo. The posted measurements included investigator-assessed progression-free survival, overall survival, and confirmed objective response rate in both a primary analysis set and a full analysis set. No primary-outcome entries were supplied in the data.

Key results

In the primary analysis set, median investigator-assessed progression-free survival was 5.59 months with tiragolumab plus atezolizumab, carboplatin, and etoposide, versus 5.39 months with placebo plus the same atezolizumab regimen. The listed log-rank analysis reported a hazard ratio of 0.65 with a 95% confidence interval of 0.43 to 0.97 and p=0.0348.

Median overall survival in the primary analysis set was 18.69 months in the tiragolumab arm and 13.54 months in the placebo arm. The corresponding listed hazard ratio was 0.89, with a 95% confidence interval of 0.56 to 1.4 and p=0.6105.

Confirmed objective response rate in the primary analysis set was 81.5% with tiragolumab and 58.9% with placebo. The listed difference in overall response rates was 22.55 percentage points, with a 95% confidence interval of 4.12 to 39.03 and p=0.0136. In the full analysis set, response rates were 77.0% and 59.7%, respectively; the listed difference was 17.37 percentage points, with a 95% confidence interval of -0.22 to 33.6 and p=0.0493.

What this means

The posted results showed a modest difference in median progression-free survival, longer median overall survival, and higher response rates for the tiragolumab-containing regimen in the reported analyses. The supplied record contains no adverse-event summary, so safety findings cannot be characterized from these data.

Source

Source: ClinicalTrials.gov, registry results for the completed Phase 3 study “Study of Atezolizumab Plus Carboplatin and Etoposide With or Without Tiragolumab in Participants With Untreated Extensive-Stage Small Cell Lung Cancer,” with primary completion dated 31 August 2023. Available at clinicaltrials.gov/study/NCT04665856.