Addition of Tiragolumab to Atezolizumab Plus Chemotherapy Did Not Improve Survival Outcomes Among Patients With Extensive-Stage Small-Cell Lung Cancer

According to results from the phase 3 SKYSCRAPER02-study, the addition of tiragolumab to atezolizumab plus carboplatin and etoposide did not significantly improve progression-free survival (PFS) or overall survival (OS) among patients with previously untreated extensive-stage small-cell lung cancer (SCLC). 

In this placebo-controlled trial, 490 patients were randomized to receive either 600 mg of tiragolumab (n = 243) or placebo (n = 247) plus 1200 mg of atezolizumab plus 4 cycles of carboplatin and etoposide followed by maintenance tiragolumab or placebo plus atezolizumab. The primary end points were investigator-assessed PFS and OS among patients without history or presence of brain metastases. Secondary end points included PFS and OS regardless of brain metastases, response, and safety.

At the data cutoff point, median duration of follow-up was 14.3 months in the primary analysis set and 13.9 months in the full analysis set. In the primary analysis set, PFS was 5.4 months in the tiragolumab arm and 5.6 months in the control arm (stratified hazard ratio [HR], 1.11; P = .3504). At a median duration of follow-up of 21.2 months, median OS in both the primary and full analysis sets was 13.1 months (stratified HR, 1.14; P = .2859). Immune-mediated adverse events occurred in 54.4% of patients in the tiragolumab arm and 49.2% of patients in the control arm. Grade 3/4 immune-mediated adverse events occurred in 7.9% and 7.7% of patients, respectively. Adverse events which lead to treatment discontinuation occurred in 8.4% of patients in the tiragolumab arm and 9.3% of patients in the control arm.

As study authors concluded, “The addition of tiragolumab to atezolizumab plus [carboplatin and etoposide] did not provide a PFS or OS benefit compared with atezolizumab and [carboplatin and etoposide] in this phase III study in patients with untreated [extensive-stage] SCLC.”

“Agents targeting the TIGIT pathway are being investigated in non–small-cell lung cancer, and we await the results of those trials,” added Thomas E. Stinchcombe, MD, Duke Cancer Center, Duke University, Durham, North Carolina.

Source: 

Rudin CM, Liu SV, Soo RA, et al. SKYSCRAPER-02: Tiragolumab in combination with atezolizumab plus chemotherapy in untreated extensive-stage small-cell lung cancer. J Clin Oncol. Published online: November 17, 2023. doi:10.1200/JCO.23.01363