The arginine deprivation therapy platform, based on our PEGylated genetically modified human arginase technology, targets cancer growth and survival by removing the supply of arginine to a proportion of cancers with disrupted urea cycle. A significant proportion of cancer types lack the ability to synthesize arginine due to deficient expression of certain metabolic enzymes of the urea cycle, including argininosuccinate synthetase 1, argininosuccinate lyase or ornithine transcarbamylase.

Our arginase biologic product, PT01 (also known as Pegtomarginase), is designed to deplete arginine from tumors with disrupted urea cycle, which we believe can halt the growth of the cancers and induce cell death. Healthy cells capable of producing sufficient levels of arginine would be largely unaffected. We believe this therapeutic has significant potential for patients both as a monotherapy as well as in combination with other Athenex therapeutics.