SAT0441 SKIN ADVERSE EVENTS WITH FEBUXOSTAT IN GOUT PATIENTSWITH PREVIOUS SKIN REACTIONS TO ALLOPURINOL. A MULTICENTRE DESCRIPTIVE STUDY
Authors: Neus Quilis Marti, Paloma Vela-Casasempere, Boris Anthony Blanco Cáceres, Cesar Diaz Torne, Enrique Calvo-Aranda, Francisca Sivera, Alejandro Prada-Ojeda, Fernando Perez-Ruiz, Eliseo Pascual, Mariano Andres
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Allopurinol is first-line urate-lowering drug (ULD) for patients with gout. However, around 10% of them refer adverse events, often at skin, which can be severe. Febuxostat is a non-purine selective xanthine oxidase inhibitor, often a therapeutic alternative in this setting, though data regarding safety in those patients with previous cutaneous adverse reactions (CAR) to allopurinol is still limited. Some cases and small retrospective series have reported skin adverse events under both allopurinol and febuxostat. <h3>Objectives:</h3> To assess the cutaneous safety of febuxostat when used in patients with previous skin reactions to allopurinol. <h3>Methods:</h3> A multicentre retrospective, descriptive study performed in seven Rheumatology units around Spain. Crystal-proven gout patients with previous CAR to allopurinol and treatment with febuxostat were selected. Demographic (age, gender), clinical (skin events, liver disease, concomitant thiazides) and laboratory variables (serum urate (SU), glomerular filtration rate) were collected. The primary study variable was the rate of patients developing CAR also with febuxostat. A descriptive analysis with estimation of 95% confidence interval (95%CI) is presented. <h3>Results:</h3> Sixty-seven gout patients with prior allopurinol-related CAR treated with febuxostat were enrolled. Their average age was 68.1 years (SD±14.8), being 49 males (73.1%). Thirteen of them were under thiazide treatment (19.4%) and average glomerular filtration rate was 66.1 ml/min (±24.3) when allopurinol was started, at a median dose of allopurinol of 100 mg/day (IQR 50-300) and mean SU of 8.9 mg/dl (±1.7). The reported CAR under allopurinol were nonspecific in 55 (82.1%), maculopapular rash in 9 (13.4%), and Stevens-Johnson's syndrome in 3 (4.5%).. Out of 67 patients, 10 developed CAR with febuxostat (14.9%; 95%CI 8.3-25.3%): nonspecific in 8 cases, one case of maculopapular rash and other of Stevens-Johnson's syndrome. Median (IQR) glomerular filtration rate, starting dose of febuxostat and SU level were 69.5 (42-87.8), 80 mg/day (40-80) and 8.2 mg/dl (7.15-9.14), respectively. Benzbromarone was initiated in all 10 patients with CAR to both allopurinol and febuxostat, and only one developed a nonspecific rash. <h3>Conclusion:</h3> In this multicentre study, around 15% of patients with prior allopurinol-related CARs also developed them with febuxostat. Further prospective and intervention studies are needed to confirm these results, though caution is recommended when using febuxostat in this subgroup of patients. <h3>Disclosure of Interests:</h3> Neus Quilis Marti: None declared, Paloma Vela-Casasempere Grant/research support from: UCB, Abbvie, Pfizer, Roche, Bristol-Myer-Squibb (another research, not BIOBADASER related), Consultant for: UCB, Lilly, Pfizer, Roche, Bristol-Myer-Squibb, Speakers bureau: Roche, UCB, MSD, Pfizer, GSK, BMS, Lilly, Boris Anthony Blanco Cáceres: None declared, Cesar Diaz Torne Consultant for: Grünenthal, Speakers bureau: Grünenthal, Enrique Calvo-Aranda Speakers bureau: Grühnental, SOBI, Menarini, Francisca Sivera: None declared, Alejandro Prada-Ojeda: None declared, Fernando Perez-Ruiz Grant/research support from: Asociación reumatólogos de Cruces, Consultant for: Grünenthal Horizon Menarini, Speakers bureau: Grünenthal, Menarini, Fundación Española Reumatologiá, Eliseo Pascual Consultant for: Eliseo Pascual has participated in the boards of Astra Zeneca, Menarini, Grunenthal and Horizon, Speakers bureau: speaking fees from Astra Zeneca and Grunenthal, Mariano Andres: None declared