Efficacy and safety of TQB2450 combined with anlotinib as maintenance therapy for LS-SCLC after definitive concurrent or sequential chemoradiotherapy: a prospective phase Ib study

There is a significant unmet need in treating patients with limited-stage small-cell lung cancer (LS-SCLC). The ETER701 study showed that Benmelstobart (TQB2450, an anti-PD-L1 antibody) combined with Anlotinib and chemotherapy achieved the longest progression-free survival (PFS) and overall survival (OS) as a first-line therapy in patients with extensive-stage small cell lung cancer (ES-SCLC). This suggests that TQB2450 and Anlotinib represent a promising treatment combination for LS-SCLC. This prospective study aimed to evaluate the efficacy and safety of TQB2450 combined with Anlotinib as maintenance therapy for LS-SCLC following concurrent or sequential chemoradiotherapy (CCRT or SCRT). Patients who did not show disease progression after chemoradiotherapy were enrolled. They received TQB2450 and Anlotinib every 3 weeks for up to 24 months. TQB2450 was intravenously administered at a dose of 1200 mg every 3 weeks. Anlotinib was initiated at a dose of 8 mg daily for days 1–14; if well tolerated, the dose was increased to 10 mg. Adverse events (AEs) were recorded using electronic data capture system. The trial was registered at the ClinicalTrials.gov (NCT05942508, 06/07/2023). Fifteen patients were enrolled in the study between May 31, 2023 and October 13, 2023. As of October 31, 2024, the median follow-up time was 15.13 months. The 12-month PFS rate was 86.7% (95% CI, 71.1–100.0), and the OS rate at 12 months was 100%. The disease control rate was 100%. AEs were reported in 13 patients (86.67%), with fatigue being the most common treatment related AE (40.00%). And two SAEs were observed (elevation in cardiac troponin T and cerebral infarction), which were determined to be unlikely unrelated to the trial drugs. Radiation pneumonitis (RP) occurred in three patients, all classified as grade 2, and one patient developed grade 1 immune-related pneumonitis. No grade 5 AEs occurred, and no patients withdrew from the study due to AEs. TQB2450 combined with Anlotinib showed promising efficacy and well tolerance in patients with LS-SCLC following first-line treatment. A randomized, double-blind, placebo-controlled Phase III clinical study (ClinicalTrials.gov Identifier: NCT06469879) is being conducted to further explore the efficacy and safety of TQB2450 combined with Anlotinib as maintenance therapy after definitive CCRT or SCRT for LS-SCLC. ClinicalTrials.gov Identifier: NCT05942508. Date of registration: 7 June 2023.