Zai Lab initiates global Phase III trial for its DLL3-targeting ADC ZL-1310

On October 20, 2025, Zai Lab registered a global Phase III clinical trial for the new DLL3 ADC drug ZL-1310 in the treatment of small cell lung cancer on Clinicaltrials.gov.

This global Phase III clinical trial plans to enroll 665 patients with advanced small cell lung cancer and is expected to be initially completed in November 2028.

ZL-1310 is a novel DLL3-targeting ADC drug developed using next-generation ADC technology. It employs a TOPO1 inhibitor as the payload, characterized by high potency, rapid clearance, and strong tissue penetration. In preclinical studies, ZL-1310 demonstrated potent antitumor activity in patient-derived xenograft (PDX) models of small cell lung cancer.

According to data presented at this year's American Society of Clinical Oncology (ASCO) Annual Meeting, ZL-1310 demonstrated an objective response rate (ORR) of 67% in second-line (2L) small cell lung cancer (SCLC). The ORR was 79% in the 1.6 mg/kg dose group, and the ORR remained at 68% in the second-line and later (2L+) treatment setting. Notably, the ORR for patients with brain metastases was also 68%.

Zai Lab anticipates submitting a New Drug Application (NDA) for the accelerated approval of ZL-1310 in the United States in 2026. Additionally, the company is exploring its potential in first-line SCLC and other neuroendocrine tumor indications.