[Efficacy and safety of low-dose rasburicase for refractory chronic gouty arthritis]

Objective: To explore the efficacy and safety of low-dose rasburicase for refractory chronic gouty arthritis. Methods: A cohort study. The clinical data of patients with refractory chronic gouty arthritis who were treated with rasburicase at Sun Yat-sen Memorial Hospital, Sun Yat-sen University between January 2021 and July 2022 were retrospectively analyzed. Refractory chronic gouty arthritis was defined as serum uric acid (sUA)>360 μmol/L and urate volume>10 cm³ under dual-energy computed tomography after tolerable maximal oral urate-lowering therapy for at least 3 months. The administration of low-dose rasburicase was applied intravenously with total dosage ranging from 4.5 to 7.5 mg each dose, at 4-week intervals for a maximum of three doses. Efficacy was evaluated by the changes of sUA level, tophus and urate volume. Results: A total of 22 patients were included for analysis, with 95.4% (21/22) male, the mean age was (44±15) years, and the median duration of gout was 11 (6-15) years. The mean sUA at baseline was (667±112) μmol/L. The levels of sUA significantly decreased after each dose of rasburicase (P<0.001), and the median reduction of sUA after each dose of rasburicase was 568 (471-635), 187 (66-335) and 123 (49-207) μmol/L, respectively. At week 12, nine patients (40.9%) exhibited sUA<360 μmol/L and tophus disappeared in one patient. The urate volume significantly decreased at week 12 when compared with that before the first dose of rasburicase in all the patients [40 (16-172) cm³ vs 17 (7-134) cm³, P<0.001], with a median reduction rate of 41.6% (22.9%-58.5%). The everall safety of rasburicase was good, and no serious adverse reactions occurred. Conclusions: Low-dose rasburicase is well-tolerated and effective for decreasing the urate burden in patients with refractory chronic gouty arthritis. Further prospective randomized controlled trials are needed to validate these findings.