Boehringer, Zai Lab Test Dual DLL3 Cancer Therapy
Boehringer Ingelheim and Zai Lab have announced a new clinical collaboration aimed at advancing a novel dual-targeting strategy for difficult-to-treat cancers. The partnership will evaluate a combination of two investigational therapies designed to target DLL3, a protein commonly expressed in aggressive tumors such as small cell lung cancer (SCLC) and neuroendocrine carcinomas (NECs).
The collaboration centers on a Phase Ib/II clinical trial that will assess the safety, tolerability, and early signs of efficacy of combining obrixtamig, Boehringer Ingelheim’s DLL3/CD3 T-cell engager, with zocilurtatug pelitecan (zoci), Zai Lab’s DLL3-targeting antibody-drug conjugate (ADC). The study will enroll patients with extensive-stage SCLC (ES-SCLC) and poorly differentiated NECs—two cancer types where treatment options remain limited and outcomes are often poor.
This dual approach represents a growing trend in oncology to combine immune-based therapies with targeted cytotoxic agents. Obrixtamig is designed to harness the body’s immune system by directing T cells to attack DLL3-expressing cancer cells. Meanwhile, zocilurtatug pelitecan delivers a potent chemotherapy payload directly to those same cancer cells, potentially enhancing anti-tumor activity while limiting systemic toxicity.
Executives from both companies highlighted the strategic rationale behind the collaboration. By pairing a T-cell engager with an ADC, the companies aim to create a synergistic effect that could improve patient outcomes beyond what either therapy might achieve alone. The approach aligns with broader industry efforts to develop “smart combinations” that address multiple mechanisms of tumor survival and resistance.
Both therapies have already shown promise in early clinical development. Obrixtamig has demonstrated encouraging signs of efficacy and a manageable safety profile in earlier studies, including in combination with chemotherapy and immunotherapy. It is currently progressing into a global Phase III trial and has received Fast Track and Orphan Drug designations from regulatory authorities in the United States and Europe.
Similarly, zocilurtatug pelitecan has reported strong and durable responses in Phase I studies involving previously treated SCLC patients, including those with brain metastases. The therapy is now being evaluated in a global Phase III registrational trial and has also received Fast Track and Orphan Drug designations from the U.S. Food and Drug Administration.
Under the terms of the agreement, Zai Lab will supply its ADC for the study, while Boehringer Ingelheim will sponsor and manage clinical operations. Each company will retain rights to its respective assets.
As the oncology field increasingly turns to combination therapies, this collaboration highlights the potential of dual-targeting strategies to address unmet needs in aggressive cancers.