ASTRIDE: Serplulimab versus atezolizumab in ES-SCLC

Safety and efficacy of serplulimab plus chemotherapy versus atezolizumab plus chemotherapy in US patients with ES-SCLC

Key takeaways:
• Serplulimab was associated with numerically longer OS than atezolizumab in ES-SCLC
• The 24-month OS rate was 32.2% with serplulimab versus 17.6% with atezolizumab
• No new safety signals were reported in the ASTRIDE study

Serplulimab plus chemotherapy was associated with numerically longer overall survival (OS) than atezolizumab plus chemotherapy in patients with extensive-stage small-cell lung cancer (ES-SCLC), according to findings from the ASTRIDE trial presented at the European Society for Medical Oncology (ESMO) Congress 2026. David R. Gandara (UC Davis Comprehensive Cancer Center, Sacramento, California, USA) reported results from the randomized study, which was conducted in a US population following a request from the US Food and Drug Administration (FDA).

What is the ASTRIDE trial in ES-SCLC?

ASTRIDE is a randomized US bridging study designed to assess whether outcomes with serplulimab plus chemotherapy in patients with ES-SCLC were consistent with those previously observed in the phase 3 ASTRUM-005 trial. Patients were randomized to receive serplulimab plus chemotherapy or atezolizumab plus chemotherapy as first-line treatment. The study was designed to descriptively compare outcomes and was not intended to establish superiority or non-inferiority.

What were the efficacy results of the ASTRIDE trial in ES-SCLC?

At a median follow-up of 14.1 months, median OS was 12.4 months with serplulimab compared with 10.2 months with atezolizumab (HR, 0.82; 95% CI, 0.56–1.20). The 24-month OS rates were 32.2% and 17.6%, respectively. Median progression-free survival was 5.4 months versus 4.9 months, while objective response rates were 65.7% and 67.0% for serplulimab and atezolizumab, respectively.

Outcomes also appeared more favorable with serplulimab among patients who had not received a prior cycle of chemotherapy before enrollment. In this subgroup, median OS was 13.4 months with serplulimab and 10.8 months with atezolizumab, while 24-month OS rates were 34.8% and 17.2%, respectively. Among patients without liver metastases, median OS was 18.9 months with serplulimab compared with 13.2 months with atezolizumab.

Overall, findings were consistent with previous evidence from the phase 3 ASTRUM-005 trial and support the applicability of those findings to a US population with ES-SCLC.

Were there any new safety signals in the ASTRIDE trial?

The incidence and severity of adverse events were reported to be comparable between treatment groups, and no new safety signals were identified. Findings were consistent with those of the phase 3 ASTRUM-005 trial and support the applicability of those results to a US patient population.

Frequently asked questions

How do serplulimab and atezolizumab differ?

Serplulimab targets PD-1, whereas atezolizumab targets PD-L1. Both agents are immunotherapies designed to enhance antitumor immune responses and have been evaluated in combination with platinum–etoposide chemotherapy for ES-SCLC. ASTRIDE directly compared the two approaches in a US population.

What was the aim of ASTRIDE, and how did it differ from ASTRUM-005?

ASTRUM-005 demonstrated the efficacy of serplulimab plus chemotherapy in a global population, whereas ASTRIDE was designed as a US bridging study to evaluate whether those findings could be reproduced in a US setting.

What do the ASTRIDE findings add to ASTRUM-005?

ASTRIDE demonstrated outcomes that were broadly consistent with findings from ASTRUM-005 in a US population with ES-SCLC. Although the study was not designed to establish superiority, the results support the applicability of ASTRUM-005 findings to US patients.

MORE LUNG CANCER RESOURCES