KRYSTEXXA is a uric acid specific enzyme which is a recombinant uricase and achieves its therapeutic effect by catalyzing the oxidation of uric acid to allantoin, thereby lowering serum uric acid. Allantoin is an inert and water-soluble purine metabolite; it is readily eliminated, primarily by renal excretion.

KRYSTEXXA (pegloticase) is a PEGylated uric acid specific enzyme indicated for the treatment of chronic gout in adult patients refractory to conventional therapy.

Limitations of Use:
KRYSTEXXA is not recommended for the treatment of asymptomatic hyperuricemia. 

Recommended Dosage: The recommended dosage is KRYSTEXXA 8 mg every two weeks given as an intravenous infusion, co administered with weekly methotrexate 15 mg orally. KRYSTEXXA alone may be used in patients for whom methotrexate is contraindicated or not clinically appropriate. 

Methotrexate with folic acid or folinic acid supplementation should be initiated at least 4 weeks prior to initiating, and throughout treatment with KRYSTEXXA. 

Discontinue oral urate-lowering agents before starting KRYSTEXXA. 

Monitor serum uric acid levels before each infusion. 

Pre-medicate patients with antihistamines and corticosteroids. 

KRYSTEXXA must be diluted prior to use. 

Do not administer as an intravenous push or bolus. The KRYSTEXXA admixture should only be administered by intravenous infusion over no less than 120 minutes via gravity feed, syringe-type pump, or infusion pump. 

Co-administration with methotrexate: The most common adverse reactions (≥5% of patients) are gout flares, arthralgia, COVID-19, nausea and fatigue. 

KRYSTEXXA alone: The most common adverse reactions (≥5% of patients) are gout flares, infusion reactions, nausea, contusion or ecchymosis, nasopharyngitis, constipation, chest pain, anaphylaxis and vomiting. 

Patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency 

Patients with history of serious hypersensitivity reactions, including anaphylaxis, to KRYSTEXXA or any of its components 

Anaphylaxis: Anaphylaxis may occur with any KRYSTEXXA infusion. Pre-medicate and monitor patients.

Infusion Reactions: Infusion reactions occurred in patients treated with KRYSTEXXA. Pre-medicate and monitor patients. 

G6PD Deficiency Associated Hemolysis and Methemoglobinemia: Screen patients at risk for G6PD deficiency. Do not administer KRYSTEXXA to patients with G6PD deficiency. 

Gout Flares: Gout flare prophylaxis is recommended for at least the first 6 months of KRYSTEXXA therapy.

Congestive Heart Failure: Congestive heart failure exacerbation may occur. Monitor patients closely following infusion.