Zai Lab Limited announced that the U.S. Food and Drug Administration has granted Fast Track Designation to Zocilurtatug pelitecan, also known as zoci and formerly identified as ZL-1310, for the treatment of extrapulmonary neuroendocrine carcinomas (epNECs) in patients whose disease has progressed following standard first-line therapy.
The designation represents another regulatory milestone for the investigational antibody-drug conjugate (ADC), which targets Delta-like ligand 3 (DLL3), a protein frequently expressed in aggressive neuroendocrine cancers. According to the company, the therapy is being developed as a potential first-in-class treatment for patients with limited therapeutic options.
Extrapulmonary neuroendocrine carcinomas are rare but highly aggressive malignancies that can arise outside the lungs in organs such as the gastrointestinal tract, bladder, cervix, and pancreas. The disease affects an estimated 100,000 people globally, and currently there are no approved targeted therapies or established standard treatments for patients whose disease progresses after first-line therapy.
Rafael G. Amado, President and Head of Global Research and Development at Zai Lab, said the new Fast Track designation highlights the potential importance of zoci for patients with difficult-to-treat cancers. He noted that this is the second Fast Track designation granted to the therapy and said the company is actively working with regulators on a potential registrational pathway for epNECs.
The FDA’s Fast Track program is designed to facilitate the development and review of therapies intended to treat serious or life-threatening conditions while addressing unmet medical needs. Benefits associated with the designation include more frequent communication with the FDA during development, the possibility of rolling regulatory review, and potential eligibility for Accelerated Approval and Priority Review.
The designation was supported in part by promising preliminary data from an ongoing multicenter Phase 1b/2 clinical trial evaluating zoci in patients with epNECs and other selected solid tumors. Findings from the registration-enabling study were presented at the 2026 American Association for Cancer Research Annual Meeting.
According to Zai Lab, heavily pretreated patients enrolled in the trial demonstrated encouraging responses to treatment. The investigational therapy achieved an objective response rate of 38.2%, suggesting meaningful antitumor activity in a patient population with few remaining options.
Researchers also reported a manageable safety profile during the study. The most common severe treatment-related adverse event observed in more than one patient was a decrease in neutrophil count, a condition that can increase infection risk but is commonly monitored in cancer treatment.
The latest FDA designation follows a previous Fast Track designation granted to zoci in May 2025 for the treatment of extensive-stage Small Cell Lung Cancer. That earlier decision reflected growing interest in DLL3-targeting therapies as potential treatment approaches for aggressive neuroendocrine cancers.
Zai Lab continues to advance zoci through clinical development as part of its broader oncology pipeline focused on targeted therapies and antibody-drug conjugates. The company said ongoing discussions with regulators are aimed at accelerating development while maintaining rigorous clinical and safety standards.
The announcement underscores continued momentum in the development of targeted cancer therapies designed to address rare and difficult-to-treat malignancies where treatment options remain limited.