Histidase-PEG 20
Histidase-PEG 20 is histidine ammonia lyase (histidase) formulated with polyethylene glycol having an average molecular weight of 20 kilodaltons (PEG 20). Histidase catabolizes histidine to urocanic acid and ammonia. Polaris is investigating the utility of Histidase-PEG 20 both as a novel treatment for various cancers and also as a potential complement to ADI, our first-in-class arginine-depleting enzyme drug. Using the company's proprietary pegylation technology, Polaris is developing a potent histidine-degrading enzyme with extended circulatory half-life.
Histidine is a semi-essential amino acid involved in normal and neoplastic growth processes. Growing tissue has a greater requirement for circulating histidine than does quiescent tissue found in healthy adults. In vitro experimentation has shown marked decrease in growth rate of cultured tumor cell lines when exposed to recombinant histidase. Depletion of circulating histidine starves cancers and could also act synergistically with arginine deiminase (ADI) in treating certain cancers.