On April 15, 2026 Boehringer Ingelheim and Zai Lab (NASDAQ: ZLAB; HKEX: 9688) reported 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.

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

"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.

(Press release, Boehringer Ingelheim, APR 15, 2026, View Source [SID1234664425])