Rapafusyn Pharmaceuticals announced the completion of its Series A financing extension, raising a total of $28 million to advance its innovative non-degrading molecular glue drug discovery platform. The financing round was led by 3E Bioventures Capital and Proxima Ventures Ltd., with participation from Lapam Capital.
The Baltimore-based company emerged from the laboratory of Dr. Jun O. Liu, Professor of Pharmacology and Molecular Sciences at Johns Hopkins University School of Medicine. Dr. Liu is recognized as a pioneer in the molecular glue field, having made the groundbreaking discovery of the molecular glue mechanism for FK506 and cyclosporin A at Harvard University with Professor Stuart Schreiber and colleagues in 1991, which formed the foundation of the non-degrading molecular glues field.
Revolutionary Platform Technology
Rapafusyn's RapaGlue™ platform represents a significant advancement in drug discovery, offering the ability to create non-degrading molecular glues by design rather than through serendipitous discovery. "Non-degrading molecular glues were previously found serendipitously. The RapaGlue™ platform has the ability to create non-degrading molecular glues by design," said Dr. Liu, scientific founder of Rapafusyn.
The platform leverages macrocyclic peptide-based non-degrading molecular glues to address challenging therapeutic targets. Rapafusyn has constructed both DNA-encoded libraries (DELs) and arrayed libraries of RapaGlues™ that form neo-protein-protein interactions (neo-PPIs) to inhibit a protein from its native activity. These compounds are rationally designed and engineered to bind FKBP and form a ternary complex with the disease target protein.
Targeting Undruggable Disease Targets
The RapaGlue™ technology can target a broad range of membrane or intracellular targets, including those traditionally difficult-to-drug, such as protein-protein interaction targets (PPIs), transcription factors, SLCs/transporters, and ion channels. This capability addresses a significant gap in the pharmaceutical industry's ability to develop therapeutics for previously undruggable targets.
"Our RapaGlue™ platform is primed to bring groundbreaking therapies to patients. This innovative non-degrading molecular glue modality integrates the benefits of molecular glues with cyclic peptides, creating cell-permeable drug candidates. Our robust platform allows us to tackle disease targets where other modalities have struggled," commented Dr. Sean Hu, CEO of Rapafusyn.
The modular architecture of RapaGlues™ enables structure-activity relationship (SAR) studies and subsequent optimization for potency, selectivity, and physicochemical properties to accelerate drug discovery and development. Notably, RapaGlues™ frequently exhibit cell permeability directly from the starting point, enhancing their potential for therapeutic development.
Investor Confidence and Market Potential
The investment round attracted significant interest from leading venture capital firms specializing in life sciences. Dr. Karen Liu, a Founding Partner at 3E Bioventures, highlighted the platform's unique capabilities: "Rapafusyn offers a new class of macrocyclic molecules that function as non-degrading molecular glues. I am excited about the platform, because for the first time in drug discovery, we have a systematic and efficient way to screen for small molecule modulators beyond the traditional Lipinski rules and protein degraders popular in recent years."
Haolin Sung, Partner at Proxima Ventures, emphasized the platform's differentiation: "We are very attracted by and delighted to invest in Rapafusyn's non-degrading molecular glue platform. It is well differentiated and, in many ways, superior to other drug modalities in addressing challenging or undruggable disease targets."
Zhihua Yu, Founding Managing Partner of Lapam Capital, noted the platform's potential impact: "By applying an innovative and well validated approach to effectively drug a broad spectrum of challenging or undruggable disease targets, Rapafusyn has the potential to address a major gap and unmet need in the pharma industry. We believe in Rapafusyn's potential to discover transformational medicines to benefit patients globally."
Future Development Plans
The $28 million in funding will propel the progress of Rapafusyn's innovative and diverse pipeline of macrocyclic peptide-based non-degrading molecular glues and further enhance its internal capabilities. The company's industry-leading libraries of RapaGlues™ can swiftly produce novel chemical entities for targets that are traditionally challenging or currently undruggable by other modalities, offering a promising solution for numerous difficult-to-drug targets and paving the way for significant advancements in drug discovery and development to address high unmet medical needs of patients.
