Boehringer Ingelheim will present new clinical data from two early-stage trials targeting the signal regulatory protein α (SIRPα) innate immune checkpoint at the upcoming 2025 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago. The data demonstrates promising results in the company's efforts to develop novel immunotherapy approaches for cancer treatment.
In a Phase 1b study, Boehringer's potential first-in-class SIRPα monoclonal antibody, BI 765063, showed a manageable safety profile and preliminary signs of immune activation when combined with the PD-1 inhibitor ezabenlimab and cetuximab. This triple combination therapy was tested in patients with recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) as a second-line treatment option.
"The preliminary results from these early-stage programs are encouraging and further strengthen Boehringer's robust immuno-oncology pipeline aimed at accelerating next-generation cancer therapies to address high unmet patient needs," said Mike Akimov, Head of Medicine, Therapy Area Oncology at Boehringer Ingelheim.
Additionally, in a separate open-label Phase I trial, the company's next-generation SIRPα monoclonal antibody, BI 770371, demonstrated favorable tolerability both as monotherapy and in combination with ezabenlimab in patients with advanced solid tumors. Notably, researchers observed no dose-limiting toxicities in either treatment arm, and the maximum tolerated dose was not reached in either group.
Dual Immune Checkpoint Blockade Strategy
Both BI 765063 and BI 770371 are designed to block what scientists call the "don't eat me" signal that cancer cells use to hide from the immune system. By targeting SIRPα, these antibodies help immune cells like macrophages recognize and destroy tumor cells, potentially enhancing the body's natural defenses against cancer.
This approach represents a novel strategy in cancer immunotherapy, as it targets the innate immune system rather than just the adaptive immune system that is typically targeted by established checkpoint inhibitors like PD-1 blockers.
"Boehringer is developing various complementary approaches to activate the immune system against cancer cells, and SIRPα blockade paired with a PD-1 inhibitor is a promising strategy," Akimov explained. "We look forward to seeing if this dual activation may lead to a broader and more sustained anti-tumor response as the programs progress."
Development Partnership and Future Plans
Both antibodies have been developed in partnership with OSE Immunotherapeutics, with Boehringer Ingelheim solely responsible for future clinical development and commercialization. Based on the current results, Boehringer has decided to move forward with the improved next-generation SIRPα inhibitor antibody BI 770371, which will now be tested in a Phase 1b study in first-line patients with R/M HNSCC.
The company's focus on head and neck cancer is significant, as this aggressive malignancy often has limited treatment options, particularly in the recurrent and metastatic setting. Current standard therapies for R/M HNSCC include platinum-based chemotherapy, EGFR inhibitors like cetuximab, and immune checkpoint inhibitors, but response rates remain suboptimal for many patients.
Presentation Details at ASCO 2025
The detailed results from both trials will be presented at the ASCO Annual Meeting, which takes place from May 30 to June 3, 2025, in Chicago:
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An Open-Label, Phase Ib Trial of the SIRPα Inhibitor BI 765063 in Combination with the PD-1 Inhibitor Ezabenlimab and Cetuximab in Patients with Head and Neck Squamous Cell Carcinoma (Abstract Number: 6019) will be presented on June 1, 2025, from 11:30am to 1:30pm CDT.
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An Open-label, Phase I Trial of the SIRPα Monoclonal Antibody, BI 770371, Alone and in Combination with the PD-1 Inhibitor Ezabenlimab in Patients with Advanced Solid Tumors (Abstract Number: 2515) will be presented on June 1, 2025, from 11:15am to 12:45pm CDT.
Advancing Cancer Immunotherapy
The development of these SIRPα inhibitors represents part of Boehringer Ingelheim's broader strategy to develop innovative cancer therapies that address high unmet medical needs. By targeting multiple immune checkpoints simultaneously, the company aims to overcome resistance mechanisms that can limit the effectiveness of single-agent immunotherapies.
The combination of SIRPα blockade with PD-1 inhibition represents a dual approach that targets both innate and adaptive immunity, potentially offering a more comprehensive immune response against cancer cells. If successful in later-stage trials, this approach could provide new treatment options for patients with difficult-to-treat cancers like head and neck squamous cell carcinoma.
As these programs advance through clinical development, oncologists and patients will be watching closely to see if this novel immunotherapy strategy can deliver on its early promise of enhanced anti-tumor activity with a manageable safety profile.
