Rapafusyn

Rapafusyn Pharmaceuticals is a Baltimore-based clinical-stage biotechnology company founded in 2015 by Professor Jun O. Liu of Johns Hopkins University School of Medicine. The company's core platform, RapaGlues™, is a proprietary library of over 8 billion non-degrading macrocyclic molecular glues derived from the natural products rapamycin and FK506 that leverage the endogenous cytosolic protein FKBP12 to selectively modulate hard-to-drug intracellular and transmembrane protein targets. Unlike traditional degrader modalities, RapaGlues are non-degrading, highly selective, cell-permeable, and demonstrate long residence times. Rapafusyn applies AI-enabled machine learning and DNA-encoded library technology to identify chemical starting points across challenging target classes including protein-protein interactions, transcription factors, SLC transporters, and enzymes. The pipeline spans oncology (GSTP1, SLC7A11), immunology and inflammation (TNFα R1-selective, STAT6), and renal disease, with its most advanced program RAP-0001 targeting ENT1 for acute kidney injury prevention in cardiac surgery patients. Based within the Johns Hopkins School of Medicine campus, Rapafusyn has raised over $62M including an oversubscribed $44M Series A in 2025.