OncoFAP-GlyPro-MB357

OncoFAP-GlyPro-MB357 is a small molecule-immunostimulator conjugate (SMIC) developed by Philogen for the treatment of solid tumors. It consists of a high-affinity small-molecule ligand, OncoFAP, which targets Fibroblast Activation Protein (FAP) expressed in the tumor stroma, linked via a FAP-cleavable Glycine-Proline (GlyPro) spacer to a proprietary Toll-like receptor 7 (TLR7) agonist payload, MB357. The conjugate is designed to selectively deliver the potent immunostimulatory payload to the tumor microenvironment, where local FAP enzymatic activity releases the active TLR7 agonist. This mechanism aims to trigger a localized immune response and long-lasting antitumor immunity while avoiding the systemic toxicities associated with non-targeted TLR activation. Preclinical data showed tumor eradication in mice, and the compound has progressed to clinical evaluation in canine patients with spontaneous solid tumors.