Chinese clinical-stage biotechnology company Nanjing Leads Biolabs Co Ltd announced on Saturday the presentation of groundbreaking clinical data from a multicentre phase Ib/II clinical trial evaluating LBL-024, an anti-PD-L1/4-1BB bispecific antibody, in combination with etoposide plus platinum-based chemotherapy for treatment-naive patients with advanced extrapulmonary neuroendocrine carcinoma (EP-NEC).

The results were featured in an oral session at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting.

Led by Professor Shen Lin of Peking University Cancer Hospital and conducted across multiple clinical centres, the study evaluates the efficacy and safety of LBL-024 combined with etoposide plus platinum-based chemotherapy as a first-line treatment for advanced EP-NEC.

Robust anti-tumour activity was observed with LBL-024 plus chemotherapy, Leads Biolabs said. In 52 efficacy-evaluable patients, the overall response rate (ORR) across all dose levels was 75.0% and the disease control rate (DCR) was 92.3%, significantly outperforming historical ORR data (30%-55%) with chemotherapy alone. In dose optimisation, 15 mg/kg demonstrated the strongest anti-tumour activity, achieving an ORR of 83.3% and a DCR of 100%. Thirty out of 52 patients (57.7%) experienced >50% tumour shrinkage. As of 15 April 2025, with a median follow-up of 8.2 months, progression-free survival (PFS) data remained immature, but trends indicate promising durability across all the dose groups. In the phase Ib dose escalation stage, no dose-limiting toxicities (DLTs) were observed. Most treatment-emergent adverse events (TEAEs) were Grade 1-2 and manageable, primarily associated with chemotherapy, including haematologic toxicity and nausea. No unexpected safety signals were identified.

Developed using Leads Biolabs' proprietary X-Body bispecific platform, LBL-024 is a potential first-in-class bispecific antibody simultaneously targeting PD-L1 and the co-stimulatory receptor 4-1BB. It is the first 4-1BB-targeting bispecific antibody globally to reach the single arm pivotal trial stage as a monotherapy and holds promise to become the first approved treatment specifically for extrapulmonary neuroendocrine carcinoma (EP-NEC), a malignancy with significant unmet medical need.

In recognition of its clinical potential, LBL-024 received Breakthrough Therapy Designation (BTD) from the National Medical Products Administration (NMPA) in China in October 2024, and Orphan Drug Designation (ODD) from the US Food and Drug Administration (FDA) for neuroendocrine carcinoma in November 2024.