SHANGHAI & CAMBRIDGE, Mass., Aug. 3, 2026

Zai Lab Limited announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to zocilurtatug pelitecan (zoci, formerly ZL-1310), its investigational DLL3-targeting antibody-drug conjugate (ADC), for the treatment of neuroendocrine carcinomas (NECs). The designation recognizes the urgent need for innovative therapies in NECs, a group of aggressive cancers associated with poor prognosis and limited treatment options. Zoci is being developed as a potential first-in-class ADC targeting Delta-like ligand 3 (DLL3), a protein highly expressed in several neuroendocrine tumors, including small cell lung cancer (SCLC) and extrapulmonary neuroendocrine carcinomas (epNECs). The latest FDA designation follows the European Medicines Agency (EMA) granting Orphan Drug Designation for pulmonary NECs, further strengthening the therapy’s global regulatory momentum and supporting its development for multiple difficult-to-treat neuroendocrine malignancies

FDA Designation Strengthens Development of First-in-Class DLL3-Targeting ADC

The newly granted Orphan Drug Designation provides Zai Lab with several important regulatory incentives, including eligibility for tax credits on qualified clinical trials, waiver of Prescription Drug User Fee Act (PDUFA) application fees, and the possibility of seven years of market exclusivity in the United States upon regulatory approval. The FDA has also previously granted Fast Track Designation (FTD) to zoci for extrapulmonary neuroendocrine carcinomas (epNECs), along with both Fast Track and Orphan Drug Designations for small cell lung cancer (SCLC). Together with the EMA’s orphan designation, these regulatory recognitions reinforce the company’s strategy to accelerate clinical development of the investigational ADC across multiple high-risk neuroendocrine cancers with substantial unmet medical need.

Zoci Targets DLL3 in Aggressive Neuroendocrine Cancers

Zocilurtatug pelitecan (zoci) is an investigational DLL3-targeting antibody-drug conjugate designed to selectively deliver anti-cancer therapy to tumors expressing Delta-like ligand 3, a validated target that is overexpressed in many aggressive neuroendocrine malignancies. According to the company, early clinical findings have demonstrated encouraging systemic and intracranial anti-tumor activity together with a potentially favorable safety profile. Zai Lab plans to launch three registration-enabling clinical studies by the end of 2026, evaluating zoci in second- and third-line small cell lung cancer, first-line SCLC, and extrapulmonary neuroendocrine carcinomas. The company also believes the therapy has the potential to become a backbone DLL3-targeting ADC in future combination regimens with immune checkpoint inhibitors and T-cell engagers, potentially reducing reliance on traditional chemotherapy.

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Regulatory Momentum Supports Zai Lab’s Global Oncology Strategy

The FDA’s latest decision marks another important milestone in Zai Lab’s global oncology development strategy, positioning zoci as one of the company’s most advanced investigational oncology assets and a potential first global oncology product launch. As a research-driven biopharmaceutical company focused on addressing diseases with significant unmet medical need, Zai Lab continues to expand its pipeline across oncology, immunology, neuroscience, and infectious diseases. With multiple registration-enabling studies scheduled to begin by the end of 2026 and growing regulatory support in both the United States and Europe, the company aims to establish zoci as a transformative targeted therapy for patients with aggressive DLL3-positive neuroendocrine carcinomas, where effective treatment options remain extremely limited.

Source:Zai Lab press release