Krystexxa manufactured by Savient Pharmaceuticals is a effectiveness in reducing uric acid levels, as well as lowering deposits of uric acid crystals in joints and soft tissues, it received FDA approval in September 2010. The EMA also approved this drug in January 2013 for treatment of tophaceous gout disorder (tophi are nodular masses of uric acid crystals). Pegloticase is a recombinant porcine-like uricase that can metabolize uric acid to allantoin, in a similar manner to the nonpegylated Rasburicase. Pegloticase is composed of four uniform chains of approximately 300 amino acids, in which nine of the 30 lysine residues in each chain are pegylated (PEG chains MW: 10 KDa). The improved solubility of Pegloticase removes the risks of precipitates forming. Furthermore, the PEG molecules in Pegloticase result in an increased drug half-life to about 10 days (in comparison with Rasburicase which is 8 h) and a reduction in its immunogenicity. Accordingly, Pegloticase is a better choice compared with other treatments, especially for chronic treatment. The side effects of Krystexxa, include infusion and allergic reactions which should be noted before repeating the treatment. Other minor side effects include sore throat, vomiting, nausea and chest pain.