Interim results from the Phase 2 HexAgon study showed that adding the OX40 agonist INBRX-106 to Keytruda improved outcomes for patients with advanced head and neck squamous cell carcinoma (HNSCC).
The combination treatment achieved a confirmed overall response rate of 44%, compared with 21.4% for Keytruda alone. Three patients receiving the combination therapy had a complete response, meaning their tumors completely disappeared, while no complete responses were seen with Keytruda alone.
Researchers noted that current standard treatments usually help only about one in four patients in this group of HNSCC patients with high PD-L1 expression.
INBRX-106 works by stimulating T cells, helping the immune system attack cancer more effectively. The treatment combination was generally well tolerated. The most common side effects included mild rash, diarrhea, fatigue, and infusion-related reactions. No treatment-related deaths were reported.
The study will continue tracking progression-free survival, and a larger Phase 3 trial is expected to begin in late 2026. Researchers also plan to test the therapy in other cancers, including non-small cell lung cancer.