FDA Grants Fast Track Designation to Zocilurtatug Pelitecan for Extrapulmonary Neuroendocrine Carcinoma

The FDA has granted fast track designation to zocilurtatug pelitecan (zoci; formerly ZL-1310) for the treatment of patients with extrapulmonary neuroendocrine carcinomas (epNECs) following progression on standard first-line therapy, according to Zai Lab, the company developing the DLL3-targeting antibody-drug conjugate.¹

The fast track designation was supported by preliminary data from the ongoing, open-label, multicenter phase 1b/2 ZL-1310-002 trial (NCT06885281), which enrolled patients with advanced or metastatic epNEC who had progressed on or after platinum-based chemotherapy, as well as patients with other selected solid tumors expressing DLL3. Results from the trial presented at the 2026 AACR Annual Meeting 2026 showed that among 34 response-evaluable patients, zoci elicited an objective response rate (ORR) of 38.2% (13 patients) and a disease control rate (DCR) of 55.9% (19 patients).^1,2,3

Moreover, the investigators observed target tumor reductions across multiple epNEC tumor types, and 1 patient previously treated with topotecan experienced a partial response. Among 18 patients with exclusively gastroenteropancreatic NECs (cohort 1), the ORR was 33.3% and the DCR was 44.4%. And among patients with other NEC subtypes and DLL3-expressing solid tumors (cohort 2), the ORR and DCR were 43.8% and 68.8%, respectively. Further, tumor size reductions were observed across epNEC subtypes throughout the evaluable population.

Regarding safety, zoci demonstrated a manageable safety profile. Neutrophil count decrease (5.2%; 3 of 58 evaluable patients) was the only grade ≥3 treatment-related adverse event occurring in more than 1 patient.^2,3

Zoci previously received fast track designation from the FDA for extensive-stage small cell lung cancer.

“This is the second FDA Fast Track Designation for zoci, underscoring the significant potential of this investigational medication to provide an important new treatment option for patients with difficult-to-treat cancers that have few available therapies,” Rafael G. Amado, MD, president, head of global research and development at Zai Lab, stated in a news release. “This designation will support our efforts to advance this novel therapy through clinical development with both the speed and quality that define our approach. We are actively engaging with health authorities on a registrational plan for epNECs.”

ZL-1310-002 Trial Design and Patient Characteristics

Zoci targets the cell surface antigen DLL3, which is overexpressed in neuroendocrine carcinomas and is generally associated with poor clinical outcomes.¹ Accordingly, investigators launched the ZL-1310-002 study to explore the DLL3-targeting agent zoci in patients with advanced or metastatic epNEC who had progressed following platinum-based chemotherapy and other prior systemic therapies.

Zoci was administered intravenously at 1.6 mg/kg every 3 weeks until disease progression or unacceptable toxicity. The data cutoff date for the AACR presentation was February 18, 2026, representing a median follow-up of 3.7 months in the phase 1b portion. Tumor response was assessed by investigator-reviewed RECIST v1.1, with additional assessment methods applied for selected NEC subtypes.

“ZL-1310 demonstrated clinically meaningful responses in patients with previously treated epNECs, aggressive malignancies with limited treatment options,” Rohit Thummalapalli, MD, gastrointestinal medical oncologist at Memorial Sloan Kettering Cancer Center, wrote in the AACR presentation with study coinvestigators.³ “Responses were observed across epNEC tumors of different primary origins. Observed response rates appear favorable in the context of historical outcomes with chemotherapy in similar settings; cross-study comparisons should be interpreted with caution.”

REFERENCES

1. Zai Lab Limited. Zai Lab receives U.S. FDA Fast Track Designation for zocilurtatug pelitecan (zoci), a DLL3-targeting ADC, for treatment of extrapulmonary neuroendocrine carcinomas (epNECs). Business Wire. Published May 11, 2026. Accessed May 12, 2026. https://tinyurl.com/2wbmwf39

2. Thummalapalli R, et al. Antitumor activity of ZL-1310 in patients with previously treated extrapulmonary neuroendocrine carcinomas (epNECs). Presented at: American Association for Cancer Research Annual Meeting 2026; April 2026; San Diego, CA. Abstract CT009.

3. Zai Lab Limited. Zai Lab presents new data demonstrating zocilurtatug pelitecan (zoci) induces rapid and robust intracranial responses in small cell lung cancer with brain metastases and promising activity in other neuroendocrine carcinomas. Business Wire. Published April 17, 2026. Accessed May 12, 2026. https://tinyurl.com/5ar76765