Gout

Number of Pegloticase Infusions in Gout Patients Who Had Uric Acid Testing Performed and Had G6PD Testing (2015-2019)

Percentage of Pegloticase Infusions in Gout Patients Who Had Uric Acid Testing Performed and Had G6PD Testing (2019 Gout Patients N = 8, Pegloticase Infusions N =81)

2016-2020

sUA = serum uric acid

G6PD = glucose-6-phosphate dehydrogenase

Pegloticase (Krystexxa®) is a pegylated uricase indicated for the treatment of chronic gout in adult patients resistant to conventional urate-lowering therapy. It is given as an IV infusion every 2 weeks. Anaphylaxis and immune reactions can occur and are based on formation of antibodies. The antibodies result in a loss of effect of the drug, which has been shown to precede the reactions in 91% of cases. Typically, uric acid levels fall below 1 mg/dL after each pegloticase; with loss of effect, uric acid levels are higher. This has led to the recommendation that a uric acid level be checked before each infusion. Treatment should be discontinued if uric acid rises to 6.0 mg/dL or higher on 2 consecutive tests.

In 2016, 42 pegloticase infusions were performed in 8 patients; serum uric acid was checked prior to infusion in all patients, and 39 were < 6.0 mg/ dL. In the 3 tests with uric acid level > 6.0 mg/dL, pegloticase was discontinued. In 2017, 55 pegloticase infusions were performed in 8 patients; serum uric acid was checked prior to infusion in all patients, and 54 were < 6.0 mg/dL. In the 1 test with uric acid level > 6.0 mg/dL, pegloticase was discontinued. In 2018, 136 pegloticase infusions were performed in 13 patients; serum uric acid was checked prior to infusion in 135/136 (99.3%) patients, and 133/136 (97.8%) were < 6.0 mg/dL. In 2019, 118 pegloticase infusions were performed in 15 patients; serum uric acid was checked prior to infusion in all patients, and 114 were < 6.0 mg/dL. All patients with uric acid > 6.0 mg/dL had pegloticase infusions discontinued. In 2020, 81 pegloticase infusions were performed in 8 patients: serum uric acid was checked prior to infusion in 80/81 patients (98.8%), and 78/81 (96.3%) were <6.0 mg/dl. All patients with 2 consecutive uric acid level > 6.0 mg/dl had pegloticase infusions discontinued.

Glucose-6-phosphate dehydrogenase (G6PD) levels should be checked prior to pegloticase infusion because of the risk for hemolysis in G6PD-deficient patients; 96.9% of patients in 2014-2017, 97.8% in 2019, 100% in 2019 and 2020 had G6PD testing.