Retention rate of IL-1 inhibitors in Schnitzler's syndrome.

OBJECTIVES: Schnitzler's syndrome is a rare autoinflammatory disease. Clinical response to IL-1 inhibitor drugs has been described, but limited information is available on the long-term efficacy and safety of these agents in Schnitzler's syndrome. METHODS: A retrospective study was conducted of patients with Schnitzler's syndrome fulfilling Strasbourg diagnostic criteria followed in 9 Italian centres. The retention rate of IL-1 inhibitors was evaluated using Kaplan-Meier analysis. RESULTS: Fifteen of 20 patients with Schnitzler's syndrome were treated with IL-1 inhibitors: in total, they received 16 courses of anakinra (median duration 20.0 months [6.0-58.3]), and 8 courses of canakinumab (median duration 19.0 months [13.5-31.0]). The retention rate of IL-1 inhibitors was 73.4% [SE 9.4] at 1 year and 63.6% [SE 10.4] at 2 years. There was no significant difference between the retention rate of anakinra and canakinumab. The retention rate was higher in patients with a definite diagnosis according to the Strasbourg criteria as compared with those with a probable diagnosis (p=0.03). At the last follow-up visit, all patients who started therapy with IL-1 inhibitors were still on treatment, although in some cases with an increased dosage compared to the start of therapy. A sparing effect on the use of conventional synthetic disease-modifying anti-rheumatic drugs and a significant reduction of prednisone dosage (p=0.02) and of serum amyloid A (SAA) levels (p=0.03) were observed. CONCLUSIONS: The retention rate of IL-1 inhibitors in patients with Schnitzler's syndrome was high, particularly in patients with a definite diagnosis according to the Strasbourg criteria, reflecting their effectiveness in the treatment of this syndrome.

Anakinra and canakinumab for patients with R92Q-associated autoinflammatory syndrome: a multicenter observational study from the AIDA Network.

BACKGROUND: This study aims at describing the therapeutic outcome of patients carrying the R92Q variant in the TNFRSF1A gene treated with anakinra (ANA) or canakinumab (CAN) and identifying any factors predictive of complete response to IL-1 inhibition. METHODS: Clinical data of patients treated with ANA or CAN for recurrent inflammatory attacks due to the presence of the R92Q variant were retrospectively collected and analysed. RESULTS: Data about 20 treatment courses with IL-1 inhibitors (16 with ANA and 4 with CAN) from 19 patients were collected. Mean age at disease onset was 20.2 ± 14.8 years. In 5 cases (26%) the R92Q variant was found in a family member affected by recurrent fever. The therapeutic response was complete in 13(68%) and partial in 2 patients (11%); treatment failure was observed in 4 cases (21%). Median AIDAI decreased from 10 (interquartile range [IQR] = 28) to 0 (IQR = 1) at the 12-month follow-up visit (p < 0.001). Mean ESR and median CRP dropped respectively from 40.8 ± 24.8 to 9.1 ± 4.5 mm/h (p < 0.001) and from 3.0 (IQR = 1.9) to 0.3 (IQR = 0.3) mg/dl (p < 0.001) after 12 months of treatment. A steroid-sparing effect was observed from the third month of treatment (p < 0.01). Thirteen patients (65%) were still on treatment at the last follow-up visit (median duration of treatment 17 (IQR = 38) months). The presence of R92Q mutation in a symptomatic relative (p = 0.022), the relapsing remitting disease course (p < 0.001) and the presence of migratory erythematous skin rashes during fever attacks (p = 0.005) were associated with complete efficacy of IL-1 inhibitors. CONCLUSIONS: R92Q patients showed a favourable response to ANA and CAN, particularly when the mutation segregated in a family member and when a relapsing-remitting disease course or TNF-α receptor-associated periodic syndrome (TRAPS) typical skin rash were observed. In the subgroup of patients not taking advantage of IL-1 blockage different molecular mechanisms underlying the autoinflammatory picture are likely to exist.