four-one-B-B / four-one-B-B ligand
A co-stimulatory checkpoint that enhances T cell and NK cell activation, proliferation, and cytokine production.
4-1BB agonism triggers multiple pro-inflammatory pathways:
Clinical development has faced challenges with hepatotoxicity, leading to exploration of tumor-targeted and next-generation agonist approaches.
What It Does: Activates T cells and NK cells to kill more effectively and live longer. Early drugs had liver safety issues, but newer versions aim to solve this.
4-1BB agonists are being developed in combination and tumor-targeted formats:
These approaches aim to maximize anti-tumor activity while minimizing systemic immune activation and associated toxicities.
Safer Approaches: New strategies try to activate 4-1BB only in the tumor, not everywhere in the body. This might work better with fewer side effects.
