Dr Mohamed on Zocilurtatug Pelitecan for Refractory Extrapulmonary NEC

Amr Mohamed, MD, discusses updated safety and efficacy findings from the phase 1/2 trial of zocilurtatug pelitecan (ZL-1310) in patients with extrapulmonary neuroendocrine carcinoma (EP-NEC) refractory to platinum-based chemotherapy. The data were presented at the 2026 North American Neuroendocrine Tumor Society (NANETS) Symposium. Mohamed is director of the Neuroendocrine Tumors Program at University Hospitals Seidman Cancer Center in Cleveland, Ohio. He explains that a primary goal of the study was to demonstrate the safety and tolerability of the agent in this population.

Any-grade adverse events occurred in approximately 92% of patients, while grade 3 treatment-related adverse events occurred in 12.8%. Treatment interruption was required in 9% of patients and dose reduction in 3%. No treatment-associated deaths or other very serious adverse events were reported. Hospitalization for a serious adverse event, not necessarily related to the drug, occurred in 4.5% of patients. The most common adverse events observed to date were nausea, vomiting, fatigue, and myelosuppression. According to Mohamed, these were mainly grade 1 or 2 and were manageable and reversible for most patients.

In the combined phase 1 and phase 2 population, the objective response rate was 40%, with a disease control rate of 55%. Mohamed notes that benefit was observed across EP-NEC subgroups, including both gastroenteropancreatic (GEP) NEC and non-GEP NEC. The combined median progression-free survival was 4.1 months, and the duration of response was 5.6 months. A subset of patients, approximately 33% of responders, achieved durable responses lasting more than 6 months.

Mohamed emphasizes that these findings are still early. The current analysis includes data from 60 of 133 patients, representing those with at least 5 months of follow-up. Additional data from the remaining patients and completion of the phase 2 study are needed before final results are available.

According to Mohamed, there has long been no good standard-of-care option in the second-line setting for patients whose disease is refractory to platinum-based chemotherapy. If the final results are positive, he explains that the next step would be a randomized phase 3 trial. That trial would compare zocilurtatug pelitecan with currently available options, such as irinotecan- or oxaliplatin-based chemotherapy, which he notes cannot truly be called standard of care. Such a trial, he says, could provide an established second-line treatment for these patients. Mohamed adds that considerable work remains in identifying a predictive biomarker for this antibody.