PhaseRx, Inc., a biopharmaceutical company, engages in developing a portfolio of products for the treatment of inherited enzyme deficiencies in the liver using intracellular enzyme replacement therapy. The company develops its products based on its proprietary Hybrid mRNA technology platform, which allows the synthesis of missing enzyme inside the cell. Its therapeutic urea cycle disorder programs under development include PRX-OTC to treat ornithine transcarbamylase deficiency; PRX-ASL to treat argininosuccinate lyase deficiency; and PRX-ASS1 to treat argininosuccinate synthetase deficiency. The company was incorporated in 2006 and is headquartered in Seattle, Washington.