4s3 Bioscience raised $20 million through a Series A financing round with KLP Enterprises to fund further development of its antibody-based technology for the delivery of protein and other macromolecular therapeutics to skeletal muscles, for the treatment of orphan neuromuscular disorders. 4s3 will work with KLP’s subsidiary Alopexx Enterprises to build and manage the firm. Alopexx was founded last year to invest in and develop preclinical and early-clinical candidates in therapeutic fields spanning infectious diseases and oncology, as well as CNS and orphan diseases.
4s3 was founded in 2007 to further develop an intracellular delivery technology based on tissue targeting via an antibody known as 3E10, and intracellular delivery via the nucleoside transporter ENT2. The firm says the ENT2 transporter is naturally enriched in skeletal muscle fibers, and is also elevated in certain cancers, providing an opportunity to develop protein therapeutic candidates that haven’t previously been deliverable to skeletal muscle and tumor tissues. 4s3’s lead preclinical-stage candidates are in development for the treatment of myotubular myopathy and myotonic dystrophy.