Boehringer Ingelheim to assess novel DLL3-targeting T-cell engager and PD-L1/VEGF-A bispecific antibody combination for small cell lung cancer

• Boehringer Ingelheim and BioNTech have entered a clinical trial collaboration and supply agreement to run a Phase Ib/II clinical study investigating complementary immuno-oncology mechanisms for extensive-stage small cell lung cancer.
• The study pairs obrixtamig, a DLL3-targeting T-cell engager, with pumitamig (BNT327/BMS986545), an investigational PD-L1/VEGF-A bispecific antibody co-developed by BioNTech and Bristol Myers Squibb
• This clinical trial partnership seeks to develop an innovative treatment regimen that delivers longer-lasting tumor control for SCLC, a cancer type with extremely high unmet medical need.

(SeaPRwire) –   Ingelheim, Germany – 9 April, 2026 – Boehringer Ingelheim announced today a clinical trial collaboration with BioNTech to evaluate a novel immuno-oncology combination therapy for extensive-stage small cell lung cancer (ES-SCLC), one of the most aggressive and underserved cancer types. Under the agreement, BioNTech will supply pumitamig (BNT327/BMS-986545), a PD-L1/VEGF-A bispecific antibody being co-developed by BioNTech and Bristol Myers Squibb, while Boehringer Ingelheim will act as the regulatory sponsor of the Phase Ib/II study. The trial aims to assess the safety, tolerability and early clinical activity of obrixtamig (BI 764532), Boehringer Ingelheim’s investigational DLL3/CD3 T-cell engager, when administered in combination with pumitamig.

SCLC is the most aggressive subtype of lung cancer, making up roughly 15–20% of all lung cancer diagnoses. It progresses rapidly, metastasizes at an early stage and almost always recurs within 12 months after initial treatment. While adding immune checkpoint inhibitors to chemotherapy has improved survival outcomes for patients with extensive-stage disease, most patients experience disease progression within months post-treatment, and prognosis remains very poor. The collaboration combines two complementary immunotherapeutic mechanisms to explore a potential new approach to strengthen and sustain antitumor immunity. Obrixtamig redirects T-cells to kill DLL3-expressing tumor cells, while pumitamig works to restore T-cells’ ability to recognize and destroy tumor cells, while simultaneously cutting off the blood and oxygen supply that fuels the tumor to prevent its growth and proliferation.

“By combining DLL3-targeted T-cell redirection with PD-L1 and VEGF pathway modulation, we aim to address two core barriers in SCLC treatment – immune evasion and an immunosuppressive, pro-angiogenic tumor microenvironment,” said Itziar Canamasas, Global Head of Oncology at Boehringer Ingelheim. “We are committed to advancing combination therapies that can deliver more durable benefits for people living with ES-SCLC.”

Obrixtamig is Boehringer Ingelheim’s investigational bispecific DLL3/CD3 T-cell engager, engineered to direct immune cells to attack DLL3-expressing cancer cells, a hallmark feature of small cell lung cancer and other neuroendocrine carcinomas. In the global Phase I first-line ES-SCLC trial DAREON®-8, when administered alongside chemotherapy and atezolizumab, obrixtamig delivered a 68% confirmed objective response rate, 89% disease control rate, and a 52% 9-month progression-free survival rate, with a positive safety profile¹. Obrixtamig is currently being evaluated across multiple global studies and is advancing into a global Phase III trial (DAREON®-Lung-1, NCT07472517). It has been granted FDA Fast Track and Orphan Drug Designations, as well as Orphan Drug status from the European Commission for neuroendocrine carcinomas.

Pumitamig is an investigational PD-L1/VEGF-A bispecific antibody being co-developed by BioNTech and Bristol Myers Squibb that combines two complementary, validated mechanisms into a single molecule – immune checkpoint inhibition and anti-angiogenesis. In a global Phase II first-line ES-SCLC study paired 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 progressed into a global Phase III trial (ROSETTA LUNG-01, NCT06712355) and received FDA Orphan Drug Designation in 2025 for the treatment of SCLC.

Per the terms of the agreement, BioNTech will supply pumitamig and Boehringer Ingelheim will serve as the regulatory sponsor of the study. Both companies retain full rights to their respective therapeutic 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 operating in both human and animal health sectors. As one of the industry’s leading investors in research and development, the company focuses on developing innovative therapies that can improve and extend lives for disease areas with high unmet medical need. Independent since its founding in 1885, Boehringer adopts a long-term perspective, integrating sustainability practices across its entire value chain. Our approximately 54,500 employees serve more than 130 markets worldwide to build a healthier and more sustainable future. 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 combined with 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) plus 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.