On April 1, 2026 Zai Lab Limited (NASDAQ: ZLAB; HKEX: 9688) reported a global clinical trial collaboration with Amgen Inc. (NASDAQ: AMGN) to evaluate Zai Lab’s investigational delta-like ligand 3 (DLL3)-targeting antibody-drug conjugate (ADC), zocilurtatug pelitecan (zoci, formerly ZL-1310), in combination with Amgen’s IMDELLTRA (tarlatamab-dlle), a DLL3-targeting Bispecific T-cell Engager (BiTE) therapy in patients with extensive-stage small cell lung cancer (ES-SCLC).

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As part of this collaboration agreement, Amgen will sponsor a global Phase 1b study to evaluate the safety and efficacy of zoci in combination with IMDELLTRA in patients with ES-SCLC. Zai Lab will retain full ownership of zoci and will supply Amgen with the study drug.

"In combination, this dual-targeting strategy has the potential to increase the rate and deepen responses both systemically and, in the brain, address resistance pathways, and unlock new treatment paradigms for patients with small cell lung cancer," said Rafael G. Amado, M.D., President, Head of Global Research and Development, Zai Lab. "These two approaches leverage complementary mechanisms — our ADC delivers a potent cytotoxic payload directly to DLL3-expressing tumor cells, while the T-cell engager is designed to activate T-cells by binding the same antigen and eliciting an immune response against the tumor."

Zoci is a DLL3-targeting ADC for small cell lung cancer. Zai Lab has presented data from a Phase 1/2 clinical trial of zoci at the EORTC-NCI-AACR (Free EORTC-NCI-AACR Whitepaper) (ENA) Symposium 2025 and the American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) 2025 Annual Meeting, demonstrating a high response rate in heavily pretreated SCLC patients, including strong intracranial activity, and a tolerable safety profile. Amgen’s IMDELLTRA received FDA approval and is currently marketed in the U.S. for the treatment of adult patients with ES-SCLC with disease progression on or after platinum-based chemotherapy. Please see full Prescribing Information, including Boxed Warnings, for IMDELLTRA.

About Zocilurtatug Pelitecan (zoci, formerly ZL-1310)

Zoci is a novel ADC in Zai Lab’s global oncology pipeline targeting DLL3, an antigen that is overexpressed in many neuroendocrine tumors, is typically associated with poor clinical outcomes, and is a validated therapeutic target for SCLC. Zoci comprises a humanized anti-DLL3 monoclonal antibody linked to a novel camptothecin derivative (a topoisomerase 1 inhibitor) as its payload. The compound was designed with a novel ADC technology platform called TMALIN, which leverages the tumor microenvironment to overcome challenges associated with first-generation ADC therapies, including off-target payload toxicity.

Zoci is being evaluated in a global development program, which includes DLLEVATE, a pivotal trial to further evaluate the safety and efficacy of zoci compared to investigator’s choice single agent therapy in patients with relapsed ES-SCLC; a phase 1b/2 trial evaluating zoci in selected solid tumors including extrapulmonary neuroendocrine carcinoma; and a phase 1a/1b trial evaluating zoci as monotherapy and in combination with atezolizumab, an immune checkpoint inhibitor, for the treatment of ES-SCLC.

Zoci’s safety profile, coupled with compelling systemic and intracranial efficacy, supports its potential as a backbone ADC in first-line combination regimens, including those that reduce the burdens of chemotherapy. Zoci received FDA Orphan Drug Designation and FDA Fast Track Designation for the treatment of SCLC.

About Small Cell Lung Cancer (SCLC)

SCLC is one of the most aggressive and lethal solid tumors, accounting for ~15% of approximately 2.5 million patients diagnosed with lung cancer worldwide each year1,2. Two-thirds of all SCLC patients are diagnosed at extensive stage3, which is associated with high rates of relapse and poor prognosis. The outcomes of the patients with ES-SCLC are dismal, with median survival of approximately 12 months following initial therapy4 and a ~5-10% overall five-year survival rate5. Treatment options have historically been limited once a patient progresses. IMDELLTRA is the first DLL3-targeting bispecific T-cell engager therapy to demonstrate an overall survival benefit in this patient population. The combination of zocilurtatug pelitecan and IMDELLTRA has the potential to build on these gains by further improving efficacy while maintaining manageable safety.

(Press release, Zai Laboratory, APR 1, 2026, View Source [SID1234664139])