540P - Phase III study of serplulimab plus chemotherapy as first-line therapy for advanced squamous non-small cell lung cancer: ASTRUM-004 Asian subgroup

Background

Adding PD-1/PD-L1 inhibitor to chemotherapy (chemo) showed improved efficacy over chemo alone in systemic treatment-naïve, unselected patient population with advanced squamous NSCLC (sNSCLC). Serplulimab is a novel PD-1 inhibitor. ASTRUM-004 is a randomised, double-blind, international phase 3 study of serplulimab plus carboplatin/nab-paclitaxel in patients with untreated advanced sNSCLC. Results of the overall population in ASTRUM-004 were reported at 2023 WCLC; here we present results of the Asian subgroup.

Methods

Patients with stage IIIB/IIIC or IV sNSCLC and no prior systemic therapy were randomised 2:1 to receive serplulimab 4.5 mg/kg or placebo (up to 35 cycles) plus chemo (carboplatin/nab-paclitaxel, 4–6 cycles) in 3-week cycles. Randomization was stratified by PD-L1 expression level (TPS ≥50% vs. 1%≤ TPS <50% vs. TPS <1%), race (Asian vs. non-Asian), and disease stage (stage IIIB/IIIC vs. IV). Primary endpoint was IRRC-assessed PFS per RECIST 1.1.

Results

Primary endpoint was met in the overall population. As of 31 January 2023, 359 Asian patients were randomised (serplulimab-chemo, n=240; placebo-chemo, n=119). With a median follow-up of 32.9 months, IRRC-assessed median PFS was longer in serplulimab-chemo group than in placebo-chemo group (9.9 vs. 5.8 months; HR 0.43, 95% CI 0.32–0.58). The HR for PFS consistently favoured serplulimab-chemo group regardless of PD-L1 expression level or disease stage. OS was prolonged with the addition of serplulimab (median, 27.4 vs. 18.4 months; HR 0.62, 95% CI 0.47–0.82). 41.3% and 23.5% patients reported immune-related adverse events (irAEs), most commonly hypothyroidism (9.6% vs. 0.8%), rash (7.5% vs. 0.8%), and immune-mediated lung disease (6.3% vs. 0.8%). Most irAEs were grade 1–2.

Conclusions

Superior efficacy and a manageable safety profile were observed when serplulimab was added to chemo in Asian patients with untreated advanced sNSCLC. Serplulimab plus chemo has been approved in China and may be recommended for this patient population.

Clinical trial identification

NCT04033354 (released on 26 July 2019).

Editorial acknowledgement

Editorial assistance was provided by Shiqi Zhong, Zhi Hao Kwok, and Chen Hu of Shanghai Henlius Biotech, Inc.

Legal entity responsible for the study

Shanghai Henlius Biotech, Inc.

Funding

Shanghai Henlius Biotech, Inc.

Disclosure

W. Kang, Q. Wang, J. Li, J. Zhu: Financial Interests, Personal, Full or part-time Employment: Shanghai Henlius Biotech, Inc. All other authors have declared no conflicts of interest.