Zai Lab Stock Jumps After FDA Grants Fast Track Designation

Zai Lab Limited (NASDAQ: ZLAB) shares climbed 7.2% on Monday after the company announced that the U.S. Food and Drug Administration granted Fast Track Designation to zocilurtatug pelitecan (zoci) for the treatment of extrapulmonary neuroendocrine carcinomas (epNECs) following progression after standard first-line therapy.

A Potential First-in-Class Therapy

Notably, the designation applies to the company’s potential first-in-class Delta-like ligand 3 (DLL3)-targeting antibody-drug conjugate. The treatment targets epNECs, an aggressive malignancy that affects approximately 100,000 people worldwide. Currently, no targeted therapies exist for this disease, and no approved standard of care addresses previously treated cases.

Furthermore, this marks the second FDA Fast Track Designation for zoci, following a similar designation for extensive-stage small cell lung cancer in May 2025. According to the company, Zai Lab is actively engaging with health authorities on a registrational plan for epNECs.

Promising Clinical Data

Last month, Zai Lab reported preliminary data from an ongoing registration-enabling multicenter Phase 1b/2 clinical trial at the American Association for Cancer Research Annual Meeting. Among heavily pretreated patients enrolled in the study, zoci delivered an objective response rate of 38.2%. In addition, the treatment showed a manageable safety profile, with neutrophil count decrease emerging as the only grade 3 or higher treatment-related adverse event occurring in more than one patient.

What Fast Track Designation Means

Importantly, Fast Track designation accelerates the development and review of new drugs that address unmet medical needs or treat serious or life-threatening diseases. The benefits include more frequent engagements with the FDA to discuss clinical development plans, as well as eligibility for Accelerated Approval and Priority Review if the drug meets the relevant criteria.

The Road Ahead

Zoci targets DLL3, a validated therapeutic target for small cell lung cancer that is overexpressed in many neuroendocrine carcinomas. Looking ahead, Zai Lab plans to launch three registration-enabling studies across second-line SCLC, first-line SCLC, and epNEC by the end of 2026.

For more investor relations information on Zai Lab Limited please visit www.ir.zailaboratory.com .