Adding tiragolumab to a combination of atezolizumab, carboplatin, and etoposide (ACE) does not improve outcomes in patients with previously untreated, extensive-stage small cell lung cancer (ES-SCLC), according to research presented at the 2022 ASCO Annual Meeting.

In the phase 3 SKYSCRAPER-02 trial, tiragolumab plus ACE did not improve progression-free survival (PFS) or overall survival (OS) when compared with ACE alone.

The trial (ClinicalTrials.Gov identifier: NCT04256421) included 490 patients with previously untreated ES-SCLC. Patients were randomly assigned to receive tiragolumab plus ACE (243 patients) or placebo plus ACE (247 patients).

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All patients had a baseline ECOG performance status of 0 or 1, more than 60% in each arm were men, more than 70% were White, nearly 20% had brain metastases, and nearly 40% had liver metastasis. The median follow-up was 14.3 months. 

The primary analysis included only those randomized patients who did not have brain metastases or a history of brain metastases at baseline. This cohort included 196 patients in the experimental arm and 201 in the control arm. 

In the primary analysis cohort, the median PFS was 5.4 months in the experimental arm and 5.6 months in the control arm (hazard ratio [HR], 1.11; 95% CI, 0.89-1.38; P =.3504). The median OS was 13.6 months in both arms (HR, 1.04; 95% CI, 0.79-1.36; P =.7963).

The full analysis included data for all randomized patients. These data also showed a lack of PFS and OS benefit in the experimental arm. 

In the full cohort, the median PFS was 5.1 months in the experimental arm and 5.4 months in the control arm (HR, 1.08; 95% CI, 0.89-1.31). The median OS was 13.1 months and 12.9 months, respectively (HR, 1.02; 95% CI, 0.80-1.30).

There was no subgroup of patients, including those with brain metastases, who benefited from the addition of tiragolumab.

Grade 3-4 treatment related-adverse events were noted in 52.3% of patients in the experimental arm and 55.7% of those in the placebo arm. Grade 5 events occurred in 0.4% and 2% of patients, respectively.

Disclosures: This research was supported by Hoffmann-La Roche. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Rudin CM, Liu SV, Lu S, et al. SKYSCRAPER-02: Primary results of a phase III, randomized, double-blind, placebo-controlled study of atezolizumab (atezo) + carboplatin + etoposide (CE) with or without tiragolumab (tira) in patients (pts) with untreated extensive-stage small cell lung cancer (ES-SCLC). Presented at ASCO 2022; June 3-7, 2022. Abstract LBA8507.