Boehringer Ingelheim to evaluate innovative combination of DLL3targeting Tcell engager plus PDL1/VEGFA bispecific antibody in small cell lung cancer

• Clinical trial collaboration and supply agreement between Boehringer and BioNTech to conduct a Phase Ib/II clinical trial to explore complementary immuno-oncology mechanisms in extensivestage small cell lung cancer.
• Study combines DLL3targeting T-cell engager obrixtamig with pumitamig (BNT327/BMS986545), an investigational PDL1/VEGFA bispecific antibody being jointly developed by BioNTech and Bristol Myers Squibb
• Clinical trial collaboration aims to develop a novel treatment regimen that delivers more sustained tumor control in SCLC, a cancer of very high unmet need.

Ingelheim, Germany 9 April, 2026 Boehringer Ingelheim today announced a clinical trial collaboration with BioNTech to evaluate a novel immunooncology combination in extensivestage small cell lung cancer (ES-SCLC), one of the most aggressive and underserved forms of cancer. Under the agreement, BioNTech will supply pumitamig (BNT327/BMS986545), a PDL1/VEGFA bispecific antibody being jointly developed by BioNTech and Bristol Myers Squibb, and Boehringer Ingelheim will be the regulatory sponsor of the Phase Ib/II study. The aim is to assess safety, tolerability and early clinical activity of obrixtamig (BI 764532), Boehringer Ingelheims investigational DLL3/CD3 Tcell engager, in combination with pumitamig.

SCLC is the most aggressive subtype of lung cancer and represents around 1520% of all lung cancer cases. It progresses rapidly, metastasizes early and almost always recurs within a year after initial treatment. While the addition of immune checkpoint inhibitors to chemotherapy has led to improved survival outcomes for patients with extensive-stage disease, most patients progress within months after treatment, and the prognosis remains poor. The collaboration combines two complementary immunotherapeutic mechanisms to explore a potential new path to enhance and sustain antitumor immunity. Obrixtamig redirects T-cells to kill DLL3 expressing tumor cells, while pumitamig aims to restore T-cells ability to recognize and destroy tumor cells while cutting off the blood and oxygen supply that feeds the tumor with the intention of preventing it from growing and proliferating.

By uniting Tcell redirection against DLL3 with PD-L1 and VEGF pathway modulation, we aim to address two central barriers in SCLC immune evasion and an immunosuppressive, proangiogenic 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 ESSCLC.

Obrixtamig is Boehringer Ingelheims investigational bispecific DLL3/CD3 Tcell engager, designed to direct immune cells to attack DLL3expressing cancer cells, a hallmark of small cell lung cancer and other neuroendocrine carcinomas. In the global Phase I firstline ESSCLC study DAREON®8, in combination with chemotherapy and atezolizumab, obrixtamig achieved a 68% confirmed objective response rate, 89% disease control rate, and a 9month progressionfree survival rate of 52%, with a favorable safety profile¹. Obrixtamig is being evaluated across multiple global studies and is advancing into a global Phase III trial (DAREON®Lung1, NCT07472517). It has received FDA Fast Track and Orphan Drug Designations, as well as Orphan Drug status from the European Commission for neuroendocrine carcinomas.

Pumitamig is an investigational PDL1/VEGFA bispecific antibody being jointly developed by BioNTech and Bristol Myers Squibb that combines two complementary, validated mechanisms in one single molecule immune checkpoint inhibition and anti-angiogenesis. In a global Phase II firstline ESSCLC study in combination with chemotherapy, pumitamig demonstrated a 76.3% confirmed objective response rate, 100% disease control rate, and median progression-free survival of 6.8 months, with a manageable safety profile². The program has advanced into a global Phase III trial (ROSETTA LUNG01, NCT06712355) and received FDA Orphan Drug Designation in 2025 for the treatment of SCLC.

Under the terms of the agreement, BioNTech will supply pumitamig and Boehringer Ingelheim will be the regulatory sponsor of the study. Both companies retain full rights to their respective assets, and the agreement is mutually non-exclusive. The trial will begin dosing patients in the second half of 2026.

Boehringer Ingelheim
Boehringer Ingelheim is a biopharmaceutical company active in both human and animal health. As one of the industrys 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

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¹ Solange Peters et al. DAREON®-8: a Phase I trial of first-line obrixtamig plus chemotherapy and atezolizumab in extensive-stage small cell lung carcinoma (ES-SCLC). ESMO 2025 Peters / Globalmedcomms (Accessed: March 2026)

² Heymach, J.V. et al. OA13.02 Global Phase 2 Randomized Trial of BNT327 (Pumitamig; PD-L1 x VEGF-A bsAb) + Chemotherapy for 1L ES-SCLC: Dose Optimization Analysis. Journal of Thoracic Oncology. 20. S38-S39. DOI: https://doi.org/10.1016/j.jtho.2025.09.074.

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