uricasebased

Uricase-based therapies refer to medical products that use uricase enzymes to metabolize uric acid. Because humans normally lack a functional uricase gene, these therapies provide an exogenous enzyme to catalyze the oxidation of uric acid to allantoin, a more soluble compound that is readily excreted.

Uricase catalyzes uric acid plus oxygen to allantoin and hydrogen peroxide. Allantoin is more soluble than uric acid, facilitating elimination in urine. Many uricase products are engineered (for example, PEGylated) to extend circulating half-life and reduce immune recognition.

Rasburicase is a recombinant urate oxidase used to prevent and treat tumor lysis syndrome by rapidly lowering serum uric acid; it is given by intravenous infusion, typically once daily for up to five days, depending on the protocol. Pegloticase is a PEGylated recombinant porcine uricase used for chronic refractory gout, administered intravenously every two weeks.

Safety and limitations: Immunogenicity can lead to anti-uricase antibodies, reducing efficacy and triggering infusion reactions. Rare cases of anaphylaxis have been reported. Rasburicase is contraindicated in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency due to risk of hemolysis and methemoglobinemia; monitoring of uric acid levels and signs of hypersensitivity is recommended.

History and scope: Uricase-based therapies emerged to provide rapid uric acid reduction in tumor lysis syndrome or in gout patients intolerant to xanthine oxidase inhibitors. Rasburicase was approved in the early 2000s, and pegylated pegloticase followed later, with separate regulatory approvals and labeling.