• Boehringer Ingelheim and Zai Lab launch a clinical collaboration to evaluate a dual DLL3‑targeting combination therapy in small cell lung cancer (SCLC) and other neuroendocrine carcinomas (NECs). 

• Phase Ib/II study will test the combination of obrixtamig, a DLL3/CD3 T‑cell engager, with Zai Lab’s zocilurtatug pelitecan (zoci), a DLL3‑targeting antibody–drug conjugate (ADC), to explore safety and potential increase in clinical benefit for patients.

Ingelheim, Germany and Shanghai, China/Cambridge, Mass. – 15 April, 2026 – Boehringer Ingelheim and Zai Lab (NASDAQ: ZLAB; HKEX: 9688) today announced a clinical collaboration focused on pioneering a dual DLL3-targeting combination. The Phase Ib/II study will assess the safety, tolerability, and initial clinical activity of combining obrixtamig, Boehringer Ingelheim’s DLL3/CD3 T-cell engager, with zocilurtatug pelitecan (zoci; formerly ZL‑1310), Zai Lab’s DLL3-targeting ADC. The study will enroll patients with poorly differentiated NECs and extensive stage SCLC (ES-SCLC); diseases where patients urgently need more effective treatment options. 

“The strategy to engage the immune system with a specific T‑cell engager and deliver a potent cytotoxic payload with a DLL3‑targeting ADC, aligns with our immuno‑oncology strategy and our drive to advance smart combinations for hard‑to‑treat cancers,” said Itziar Canamasas, Ph.D., Global Head of Oncology at Boehringer Ingelheim. “It’s another step in our mission to expand effective options for people with DLL3‑expressing cancers.” 

“Zoci has shown encouraging activity and good tolerability in SCLC,” said Rafael G. Amado, M.D., President, Head of Global Research and Development at Zai Lab. “We have rapidly advanced zoci into pivotal stage and are pursuing opportunities to explore multiple combination approaches in SCLC and other NECs. This collaboration with Boehringer Ingelheim offers a compelling DLL3‑targeting strategy with the potential to benefit patients who urgently need better treatments.” 

Obrixtamig is Boehringer Ingelheim’s investigational bispecific DLL3/CD3 T‑cell engager, designed to direct the body’s own immune cells to attack DLL3‑expressing cancer cells, a hallmark of SCLC and certain NECs. In the global Phase I first‑line ES‑SCLC study DAREON®‑8, in combination with chemotherapy and atezolizumab, obrixtamig showed encouraging signs of early clinical efficacy and a manageable safety profile1. Obrixtamig is being evaluated across multiple global studies and is advancing into a global Phase III trial (DAREON®‑Lung‑1, NCT07472517). The molecule has received FDA Fast Track Designation and Orphan Drug Designation from both the FDA and the European Commission for neuroendocrine carcinomas. 

Zocilurtatug pelitecan is Zai Lab’s DLL3targeting ADC engineered to deliver a potent cytotoxic payload to DLL3positive tumor cells in ES-SCLC. Updated global Phase I results in previously treated ES-SCLC show strong and durable responses, including in patients with brain metastases, along with a favorable safety profile. On this basis, the program has advanced into a global Phase III registrational study. In addition to SCLC, zoci is being evaluated in NECs. Zoci has received FDA Orphan Drug Designation and FDA Fast Track Designation for the treatment of SCLC.  

Under the terms of the agreement, Zai Lab will supply its DLL3‑targeting ADC for the study, while Boehringer Ingelheim will sponsor and oversee day‑to‑day clinical operations. Each company retains the rights to its respective assets. 

Boehringer Ingelheim 

Boehringer Ingelheim is a biopharmaceutical company active in both human and animal health. As one of the industry’s top investors in research and development, the company focuses on developing innovative therapies that can improve and extend lives in areas of high unmet medical need. Independent since its foundation in 1885, Boehringer takes a long-term perspective, embedding sustainability along the entire value chain. Our approximately 54,500 employees serve over 130 markets to build a healthier and more sustainable tomorrow. Learn more at www.boehringer-ingelheim.com. 

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 carcinomas, 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 potential best-in-class 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 Zai Lab 

Zai Lab (NASDAQ: ZLAB; HKEX: 9688) is an innovative, research-based, commercial-stage biopharmaceutical company based in China and the United States. We are focused on discovering, developing, and commercializing innovative products that address medical conditions with significant unmet needs in the areas of oncology, immunology, neuroscience, and infectious disease. Our goal is to leverage our competencies and resources to positively impact human health. 

For additional information about Zai Lab, please visit www.zailaboratory.com or follow us at https://x.com/ZaiLab_Global. 

Intended Audiences Notice 

This press release is issued from our Corporate Headquarters in Ingelheim, Germany and is intended to provide information about our global business. Please be aware that information relating to the approval status and labels of approved products may vary from country to country, and a country-specific press release on this topic may have been issued in the countries where we do business. 

Zai Lab Forward-Looking Statements 

This press release contains forward-looking statements relating to our future expectations, plans, and prospects, for Zai Lab, including, without limitation, statements relating to our prospects and plans for developing and commercializing next generation ADCs, including zocilurtatug pelitecan, the potential benefits of zocilurtatug pelitecan, and the potential treatment of SCLC and other neuroendocrine carcinomas. These forward-looking statements may contain words such as “aim,” “anticipate,” “believe,” “could,” “estimate,” “expect,” “forecast,” “goal,” “intend,” “may,” “plan,” “possible,” “potential,” “will,” “would,” and other similar expressions. Such statements constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements are not statements of historical fact or guarantees or assurances of future performance. Forward-looking statements are based on our expectations and assumptions as of the date of this press release and are subject to inherent uncertainties, risks, and changes in circumstances that may differ materially from those contemplated by the forward-looking statements. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including but not limited to (1) our ability to successfully commercialize and generate revenue from our approved products, (2) our ability to obtain funding for our operations and business initiatives, (3) the results of our clinical and pre-clinical development of our product candidates, (4) the content and timing of decisions made by the relevant regulatory authorities regarding regulatory approvals of our product candidates, (5) risks related to doing business in China, and (6) other factors identified in our most recent annual and quarterly reports and in other reports we have filed with the U.S. Securities and Exchange Commission (SEC). We anticipate that subsequent events and developments will cause our expectations and assumptions to change, and we undertake no obligation to update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise, except as may be required by law. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this press release. 

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