ZLAB Zai Lab Limited (NASDAQ: ZLAB), a leading commercial-stage biopharmaceutical company focused on discovering and delivering transformative medicines for patients in China and globally, today announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to ZL-1310, its investigational DLL3-targeted antibody-drug conjugate, for the treatment of extensive-stage small cell lung cancer (ES-SCLC).The designation follows the earlier Fast Track designation granted in May 2025, reflecting the FDA’s recognition of ZL-1310’s potential to address an area of high unmet medical need. Zai Lab also reported that it has completed enrollment for its Phase 1b dose-expansion cohort and expects to initiate a global Phase 2/3 pivotal trial by Q4 2025.
“This Orphan Drug Designation is an important regulatory milestone as we continue to rapidly advance ZL-1310 through clinical development,” said Dr. Alan Yeung, Chief Medical Officer at Zai Lab. “We remain committed to delivering a new, effective therapeutic option for patients facing the urgent challenges of small cell lung cancer.”
ZL-1310 is designed to selectively target DLL3, a protein highly expressed in SCLC but absent in most normal tissues, enabling potent and targeted cytotoxic delivery. Interim data have shown promising antitumor activity and a manageable safety profile.