Zai Lab (Nasdaq: ZLAB) announced receipt of US FDA orphan drug designation for zocilurtatug pelitecan (zoci, formerly ZL-1310), its delta-like ligand 3 (DLL3)-targeting antibody-drug conjugate (ADC), for the treatment of neuroendocrine carcinomas (NECs). The FDA award covers a broader indication than the EMA orphan drug designation granted in June 2026, which was scoped to pulmonary NECs only. Zai Lab said NECs have no approved targeted therapies and no standard of care for previously treated patients.
The designation may provide development incentives including tax credits, user-fee exemptions, and, if ultimately approved for the indication, seven years of US orphan exclusivity.
Zoci is being evaluated across multiple ongoing studies, including a global Phase III registrational trial (DLLEVATE) in relapsed extensive-stage small cell lung cancer (ES-SCLC), and a Phase I/II study (NCT06885281) in extrapulmonary neuroendocrine carcinomas (epNECs) and other selected solid tumors. Data presented at AACR 2026 from the epNEC cohort showed a 38.2% confirmed objective response rate across pretreated patients, with neutrophil count decrease as the only Grade ≥3 treatment-related adverse event occurring in more than one patient. Zai Lab has also entered a collaboration with Amgen to evaluate zoci in combination with tarlatamab-dlle (Imdelltra), a DLL3/CD3 bispecific T-cell engager, in ES-SCLC.