Gout

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

Number of Pegloticase Infusions in Gout Patients Who Had Uric Acid Testing Performed and Had G6PD Testing (2019 Gout Patients N = 15, Pegloticase Infusions N =118)

2015-2019

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 2015, 77 pegloticase infusions were performed in 9 patients; serum uric acid was checked prior to infusion in all patients, and 76 were < 6.0 mg/dL. In the 1 test with uric acid level > 6.0 mg/dL, pegloticase was discontinued. 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.

Glucose-6-phosphate dehydrogenase (G6PD) levels should be checked prior to pegloticase infusion because of the risk for hemolysis in G6PD-deficient patients; 96.6% of patients in 2015-2019 and 97.8% in 2019 had G6PD testing.