Boehringer Ingelheim has announced a clinical trial collaboration with BioNTech to test a new immuno-oncology combination in extensive-stage small cell lung cancer (ES-SCLC), one of the most aggressive and difficult-to-treat forms of cancer.

 

Under the agreement, BioNTech will supply pumitamig, a PD-L1/VEGF-A bispecific antibody co-developed with Bristol Myers Squibb, while Boehringer Ingelheim will act as the regulatory sponsor of a Phase Ib/II study. 

 

The trial will evaluate pumitamig in combination with Boehringer’s investigational DLL3/CD3 T-cell engager, obrixtamig, with the goal of assessing safety, tolerability, and early signs of clinical activity.

 

Small cell lung cancer is highly aggressive, accounting for roughly 15–20% of all lung cancer cases. It spreads early, progresses rapidly, and almost always returns within a year. Although immune checkpoint inhibitors combined with chemotherapy have improved outcomes in extensive-stage disease, most patients still relapse within months and survival remains poor.

 

The new collaboration brings together two distinct immune strategies: obrixtamig redirects T-cells to kill DLL3-expressing tumor cells, while pumitamig combines immune checkpoint blockade with anti-angiogenesis activity to both restore immune recognition and disrupt the tumor’s blood supply.

 

“By uniting T-cell redirection against DLL3 with PD-L1 and VEGF pathway modulation, we aim to address two central barriers in SCLC – immune evasion and an immunosuppressive, pro-angiogenic microenvironment,” said Itziar Canamasas, Global Head of Oncology at Boehringer Ingelheim. 

 

“We are committed to advancing combinations that could deliver more durable benefit for people living with ES-SCLC.”

 

Obrixtamig is a bispecific DLL3/CD3 T-cell engager designed to direct immune cells against DLL3-expressing tumors, a hallmark of Small cell lung cancer. 

 

In the Phase I DAREON-8 study in first-line ES-SCLC, combined with chemotherapy and atezolizumab, it achieved a 68% confirmed objective response rate, 89% disease control rate, and a 52% 9-month progression-free survival rate, with a favorable safety profile. 

 

The therapy is now advancing into a global Phase III trial and holds multiple regulatory designations, including FDA Fast Track and Orphan Drug status.