Zai Lab reports Phase 1 data showing zocilurtatug pelitecan demonstrates strong intracranial responses in ES-SCLC patients with brain metastases and activity in neuroendocrine tumors.
Written By: Samiksha Jadhav, BPharm
Reviewed By: Pharmacally Editorial Team
Zai Lab Limited has reported clinical data demonstrating that its investigational antibody-drug conjugate (ADC), zocilurtatug pelitecan (zoci; ZL-1310), shows meaningful intracranial activity in patients with previously treated extensive-stage small cell lung cancer (ES-SCLC) and brain metastases.
The findings, to be presented at the AACR Annual Meeting 2026, are based on an ongoing global Phase 1 trial (NCT06179069) evaluating zoci in a population with poor prognosis and limited treatment options.
In the study, 136 patients were treated, of whom 36% had baseline brain metastases. Among evaluable patients, the intracranial objective response rate (iORR) was 53.7%, including seven complete responses, while at the 1.6 mg/kg dose, the iORR reached 62.5% with four complete responses. Tumor reductions were observed across dose levels and in patients regardless of prior radiotherapy.
Zoci demonstrated a manageable safety profile, with grade 3 or higher treatment-related adverse events occurring in 19.9% of patients overall, most commonly hematologic toxicities such as neutropenia and anemia, and no treatment-related neurologic serious adverse events reported.
According to Luis Paz-Ares M.D. Ph.D., Senior Investigator, the data are encouraging given the limited efficacy of current therapies for ES-SCLC patients with brain metastases, noting that the observed responses across dose cohorts and irrespective of prior radiotherapy suggest potential for zoci to address a significant unmet need.
Additional data from a Phase 1b/2 study (NCT06885281) in extrapulmonary neuroendocrine carcinomas (epNECs) and other solid tumors showed an objective response rate of 38.2% and a disease control rate of 55.9% in pretreated patients, with tumor reductions across multiple subtypes and a consistent safety profile. These findings indicate potential activity of zoci across DLL3-expressing neuroendocrine malignancies that currently lack approved standard therapies.
Rafael G. Amado, M.D., President, Head of Global Research and Development at Zai Lab stated that the results highlight the breadth of the company’s oncology pipeline and support rapid advancement of zoci into pivotal development, with three registration-enabling studies planned by the end of 2026 as part of its strategy toward a potential global oncology launch.
The company will also present preclinical data on additional oncology candidates, including ZL-6201, an LRRC15-targeting ADC, and ZL-1222, a PD-1/IL-12-based immunocytokine, both aimed at expanding treatment options across solid tumors. Overall, the data support further clinical development of zoci as a potential treatment option in small cell lung cancer and other aggressive neuroendocrine cancers.
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About the Writer
Samiksha Vikram Jadhav is a B.Pharm graduate with a strong academic foundation in pharmaceutical sciences, pharmacology, and drug development. She has a keen interest in healthcare advancements, clinical research, medical writing, and emerging therapies. Her work focuses on presenting developments in the pharmaceutical and healthcare sectors through clear and accurate scientific communication.