RBT-101

**RBT-101** is a multivalent, multibody agonist of 4-1BB (TNFRSF9) developed by Radiant Biotherapeutics using their proprietary Multabody™ platform, which employs apoferritin scaffolding and protein engineering to create antibodies with enhanced potency, tunability, and safety. Unlike traditional 4-1BB agonists like urelumab, RBT-101 achieves robust, durable tumor regression in preclinical models such as MC38 colorectal cancer without liver or spleen toxicity by mimicking natural ligand biology and avoiding Fc-mediated adverse effects. It demonstrated complete tumor regression, long-lived anti-tumor immunological memory upon re-challenge, and is Radiant's lead oncology program in preclinical development for neoplasms.[1][3][9]