Rapafusyn Pharmaceuticals is a Baltimore-based, clinical-stage drug discovery company spun out of Johns Hopkins University. Its RapaGlue platform designs non-degrading, cell-permeable macrocyclic molecular glues that modulate hard-to-drug intracellular and transmembrane targets - drawing on a proprietary DNA-encoded library of more than 8 billion compounds and machine learning for target selection. The lead program, RAP-0001, is a selective ENT1 inhibitor advancing toward IND-enabling studies for the prevention of acute kidney injury in cardiac surgery patients, with a broader pipeline spanning oncology, immunology, and pain.
Sean X. Hu is the President and CEO of Rapafusyn Pharmaceuticals, a Baltimore-based biotech spun out of Johns Hopkins that is building a library of natural-product-like macrocycles it calls RapaGlues. He is a genomics PhD turned Wharton MBA turned management consultant turned operator, with prior stops at Bristol Myers Squibb, CuraGen, Illumina, AT Kearney, IMS, Bionest, BioStrat, GlobalData, and Avotres. In September 2025 he closed an oversubscribed $44M Series A led by BioTrack Capital and Yonjin Capital to push RapaGlues into difficult-to-drug targets.
Circle Pharma is a South San Francisco biotechnology company building intrinsically cell-permeable, orally available macrocycle therapeutics to hit cancer targets long considered undruggable. Spun out of UCSF and UC Santa Cruz in 2012, it pairs structure-based design, AI/ML, physics-based simulation, and advanced synthetic chemistry in its proprietary MXMO platform. Its lead program, CID-078, is a first-in-class oral cyclin A/B RxL inhibitor now in a Phase 1 trial for advanced solid tumors. The company has raised more than $200 million in total funding, including a $90 million Series D in 2024.