2181 - The 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

X. Yin¹, K. Zhao¹, L. Liu¹, L. Kong¹, L. Jiang¹, X. Jing², H. Zhu¹, X. Dong³, X. Wang³, J. Yu⁴, and X. Meng¹; ¹Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, ²Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China, ³Chia Tai Tianqing Pharmarceutical Group Co., Ltd, China, Nanjing, China, ⁴Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China

Purpose/Objective(s): Up to now, no study about immunotherapy successfully prolonged the survival of limited stage small cell lung cancer (LS-SCLC). In 2023 WCLC conference, the ETER701 study showed Benmelstobart (TQB2450, an anti-PD-L1 antibody) with Anlotinib plus chemotherapy achieved the historically longest PFS and OS as first-line therapy in extensive stage small cell lung cancer (ES-SCLC) patients. TQB2450 and Anlotinib may be also a promising regimen for LS-SCLC. The study aims to assess the efficacy and safety of Benmelstobart (TQB2450) combined with Anlotinib as maintenance therapy for LS-SCLC after concurrent or sequential chemoradiotherapy. Materials/

Methods: Eligible patients were aged 18-75 years with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 who had not progressed after concurrent or sequential chemoradiotherapy. Patients received TQB2450 and Anlotinib every 3 weeks up to 24 months. TQB2450 was intravenously every 3 weeks at a dose of with 1200 mg. To decease the toxicity of combination treatment regimen, Anlotinib began at the dose of 8mg d1-14 (if the patients tolerated well, the dose will be elevated to 10mg). The adverse events (AE) were collected by electronic data capture (EDC) system. The trial is registered with ClinicalTrials.gov, NCT05942508.
Results: Between May 31, 2023 and Oct 13, 2023, 15 patients were successfully enrolled in the study. Study treatment was received by all patient, median follow-up time was 6.5 months. Up to March 08, 2024, the disease of 14/15 patients were well controlled. The most treatment-related adverse events were thyroid dysfunction (33%), fatigue (33%) and decreased white blood cell count (33%). None of the patients discontinue all the treatment due to treatment-related adverse events. The pneumonia was observed in four patients (26.7%, three grade 2, one grade 1), all related with radiotherapy. Treatment related grade 3 AE occurred in 2 patients (13.3%, 1 hyperkalemia and 1 abdominal distension). No grade 4 and grade 5 AE occurred.
Conclusion: The TQB2450 and Anlotinib was well tolerated without grade 4 or 5 adverse events. The efficacy is promising. A multi-center randomized, double-blind phase III trial will be carried to further explore the efficacy and safety of TQB2450 combined with Anlotinib as maintenance therapy for LS-SCLC after definitive concurrent or sequential chemoradiotherapy.