Consolidation serplulimab following concurrent hypofractionated chemoradiotherapy for limited-stage SCLC: Preliminary analysis of phase II ASTRUM-LC01 study

BackgroundSerplulimab plus chemotherapy has been well-established as a standard first-line treatment for extensive-stage small-cell lung cancer (SCLC) via the ASTRUM-005 trial. However, its role as consolidation monotherapy in limited-stage SCLC (LS-SCLC) remains uncertain.MethodsThis multicenter, phase â…¡ trial (ASTRUM-LC01) has been registered at ClinicalTrials.gov (NCT05443646). We enrolled LS-SCLC patients who did not progress after 4 cycles of standard chemotherapy, concurrent hypofractionated radiotherapy (45Gy/3Gy/15F), and prophylactic cranial irradiation (25Gy/2.5Gy/10F). These patients then received consolidation serplulimab 300mg every 3 weeks for up to 1 year until progression or unacceptable toxicity. This preliminary analysis aimed to evaluate the objective response rate (ORR), depth of response (DpR), disease control rate (DCR), survival outcomes, and safety profile.ResultsBetween May 2022 and August 2023, 55 patients were enrolled, 69.1% being male and 81.8% at stage â…¢. The median age was 60 years. The date of data cut-off was April 7, 2024. The median follow-up duration since initiating serplulimab was 9.8 months, and 31 (56.4%) patients remained on treatment. The median cycles of consolidation therapy were 8, and 9 (16.4%) patients had completed the prescribed treatment. The ORR and DCR following serplulimab treatment were both 96.4% (95% CI 87.5-99.6), and 90.9% of patients achieved a DpR exceeding 50%. The median PFS was not reached, with a 1-year PFS rate of 71.8% (95% CI 60.1-85.8) from the first dose of consolidation therapy. Treatment-related adverse events (TRAEs) were reported in 72.7% of patients, with 14.6% experiencing grade 3-4 TRAEs, and pneumonitis (5.45%) being the most common. Four patients discontinued the study due to TRAEs, and no treatment-related death event was reported.ConclusionsThese results highlight the potential survival benefit and manageable safety of consolidation serplulimab therapy in LS-SCLC.Clinical trial identificationNCT05443646.Legal entity responsible for the studyY. Wu.FundingShanghai Henlius Biotech, Inc. (2696.HK).DisclosureAll authors have declared no conflicts of interest.