Pegloticase and the patient with treatment-failure gout.

Gout is an inflammatory arthritis characterized by sudden, painful inflammation. Gout can affect any joint in an asymmetric distribution. Gouty attacks may be isolated or can be followed by years of recurrent flares. Over time, elevated serum urate levels and tophaceous deposits can lead to deformity and disability from underlying bony erosion. The concept of 'treatment-failure gout' describes a unique population that has been either unable to tolerate allopurinol or who have not experienced normalization of serum urate levels on allopurinol. It is estimated that approximately 1-1.5% of the estimated 3-8 million people with gout in the USA have treatment-failure gout. Pegloticase is an US FDA-approved intravenous medication that is a mammalian recombinant uricase conjugated to monomethoxy polyethylene glycol. Two recent Phase III trials have found pegloticase to be effective in the management of treatment-failure gout. These studies also highlight safety concerns regarding the drug's immunogenicity.