Data Readout

Zai Lab's DLL3 ADC zoci nears first combo readout in frontline SCLC

A dose-escalation and expansion trial testing zoci with atezolizumab, with and without chemotherapy, in untreated small-cell lung cancer is set to post data in the second half of 2026.

By AppliedXLJuly 13, 2026Trial NCT06179069

Executive Summary

Zai Lab is heading into a data disclosure window for its DLL3-targeted antibody-drug conjugate in patients starting treatment for extensive-stage small-cell lung cancer, testing it alongside standard immunotherapy and chemotherapy rather than alone.
Moving the drug into the first-line combination setting, rather than only later-line monotherapy, is the step that determines whether Zai Lab can advance it toward registration-enabling trials, which the company has said it intends to start by the end of 2026.
DLL3 is no longer an unproven target: multiple sponsors, most prominently Amgen with tarlatamab, are already running combination studies in the same disease, so the readout lands into a field with an established mechanism rather than a novel one.
The sponsor has held the same second-half-2026 guidance across two consecutive quarters, and the underlying trial's enrollment and protocol changes to date look like routine early-phase trial management rather than signs of a program under strain.

The catalyst

Zai Lab Limited has guided to a data readout from the Phase 1 combination portion of its zocilurtatug pelitecan (zoci) trial in first-line extensive-stage small-cell lung cancer, with the disclosure expected sometime in the second half of 2026. The trial, registered as NCT06179069, is testing the DLL3-targeted antibody-drug conjugate as a single agent and in combination with atezolizumab, with and without carboplatin, across four parts of the protocol. Chief Executive Officer Samantha Du said in February that the company accelerated "the rapid progression of zoci into pivotal development, enabled by our integrated U.S./China infrastructure". The frontline combination arms, rather than the later-line monotherapy cohorts, are the portion of the study that would carry that transition forward. Zai+1

Probability of Success

Endpoint Met49%

Completes48%

Clinical Significance19%

Regulatory86%

Trial design and timing

NCT06179069 is Recruiting, targets enrollment of 339 patients across the United States, China, and Spain, and lists a primary completion date of May 30, 2027, more than a year past the guided readout window. That gap is normal for an early-phase trial reporting interim data ahead of full completion: the primary endpoints, dose-limiting toxicity and treatment-emergent adverse-event rates across each combination part, plus antitumor activity by RECIST v1.1, are designed to be assessed on a rolling basis as cohorts mature, not at a single readout. The trial's enrollment target rose from 140 at first posting to 339 as of April 2026, an increase typical for a multi-part, multi-cohort Phase 1 design that is not itself a signal of distress. NCT06179069

Regulatory backdrop

The FDA granted zoci Orphan Drug Designation for small-cell lung cancer in January 2025 and Fast Track Designation for extensive-stage disease in May 2025. Both designations reflect unmet need in the disease rather than a judgment on this trial's data, and neither predicts what the frontline combination cohorts will show. Zai

The competitive field

DLL3 is an active target in small-cell lung cancer, with roughly 45 DLL3-directed programs and 8 active industry trials tracked against it, most visibly Amgen's tarlatamab, which is already in randomized combination testing in the same disease and carries regulatory approval history of its own. Zoci's positioning is as an antibody-drug conjugate rather than the bispecific T-cell engager mechanism tarlatamab and several DLL3 peers use, a modality distinction that could matter for tolerability in a frontline chemo-immunotherapy combination, though the trial has not yet disclosed a safety profile to test that against. No sponsor has yet reported combination data for a DLL3-directed agent specifically in the untreated, first-line setting Zai Lab is now testing, so this readout would be an early data point for that specific combination question rather than a replication of an established result. NCT06179069

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