Two firms launch for siRNA drugs

Two start-ups have launched to develop next-generation drugs using small interfering RNA (siRNA) to silence genes. The first, Judo Bio, is a spin-off of the venture capital firm Atlas Venture. The company spent about 3 years in stealth while designing a drug candidate that combines a ligand with siRNA that should silence messenger RNA (mRNA) and, in turn, reduce the number of certain solute carrier proteins that are involved in disease. While siRNA is a proven therapeutic approach, getting it to the right cell types is challenging. The kidney is a “very complex tissue,” says Chief Scientific Officer Alfica Sehgal, a former head scientist at RNA biotech firms Camp4 Therapeutics and Alnylam Pharmaceuticals. The organ consists of multiple tissue types, making specificity difficult. The glomerulus, a network of blood vessels in the kidney, also filters out molecules by size; it excretes siRNA by default. “It’s not an easy bean to