ABOUT KRYSTEXXA ® KRYSTEXXA ® (pegloticase) is a PEGylated uric acid specific enzyme for administration by intravenous infusion. The active substance pegloticase is a covalent conjugate of uricase produced by a genetically modified strain of Escherichia coli and monomethoxypoly (ethylene glycol). Pegloticase catalyses the conversion of uric acid into the inert highly water-soluble metabolite allantoin, with hydrogen peroxide and carbon dioxide as oxidative by-products. Allantoin is eliminated by renal excretion, thereby rapidly lowering serum uric acid. This induces a concentration gradient between serum uric acid and tissue/joints deposits of monosodium urate resulting in the migration of urate from tissues/joints, which makes it accessible to conversion to allantoin.IMPORTANT SAFETY INFORMATION ABOUT TREATMENT WITH KRYSTEXXA ® KRYSTEXXA ® is not indicated for the treatment of asymptomatic hyperuricemia. Patients who are at risk of having a condition known as G6PD deficiency should be screened by their physician prior to starting therapy with KRYSTEXXA. Discontinue oral urate-lowering therapies before instituting KRYSTEXXA and do not institute oral urate-lowering therapy while the patient is on KRYSTEXXA therapy. Possible side effects of KRYSTEXXA include:
- Anaphylaxis which occurred in some patients treated with KRYSTEXXA. KRYSTEXXA should be administered in healthcare settings and by healthcare providers prepared to manage anaphylaxis. Patients should be pre-medicated with antihistamines and corticosteroids. Patients should be closely monitored for an appropriate period of time for anaphylaxis after administration of KRYSTEXXA.
- Infusion reactions which occurred in some patients treated with KRYSTEXXA. The risk of an infusion reaction is higher in patients who have lost therapeutic response. Because the risk of infusion reactions is higher in patients who lose therapeutic response to KRYSTEXXA, monitor serum uric acid before each infusion and consider discontinuing treatment if levels rise above 6mg/dL, particularly when two consecutive levels above 6 mg/dL are observed.
- As with other urate-lowering therapies, an increase in gout flares was seen in some patients treated with KRYSTEXXA. Gout flare prophylaxis with a non-steroidal anti-inflammatory drug (NSAID) or colchicine is recommended starting at least 1 week before initiation of KRYSTEXXA therapy and lasting at least 6 months, unless medically contraindicated or not tolerated.