Background: Familial Mediterranean Fever (FMF), Hyper IgD Syndrome/Mevalonate Kinase Deficiency (HIDS/MKD), Tumor Necrosis Factor Receptor-associated Periodic Syndrome (TRAPS) and Systemic Juvenile Idiopathic Arthritis (SJIA, Still’s disease) are autoinflammatory diseases causing serious burden to patients due to severe systemic and organ inflammation mainly caused by increased production of interleukin-1β (IL-1β). In clinical trials as well as in real-life, the human monoclonal antibody canakinumab (CAN) effectively inhibits IL-1β. CAN is approved and reimbursed for these indications, within the Belgian national healthcare system.

Objectives: To describe patient demographics, quantitative use, dosing, and treatment discontinuations of CAN over 5 years in real-life in Belgium in FMF, TRAPS, HIDS/MKD and SJIA patients.

Methods: This is a national, non-interventional, partly retrospective, and partly prospective registry of patients (from 2 years of age) who granted reimbursement and are treated with CAN in Belgium. The maximum observation period was 5 years (1 July 2018 to 30 June 2023).

Results: 96 patients were included in 9 centers (54.2% female, 44.8% male, 12.5% <18 years and 87.5% ≥18 years). The mean age at CAN initiation was 34.6 years. Respectively 79.2%, 13.5%, 6.3% and 7.3% received CAN for FMF, TRAPS, HIDS/MKD, and SJIA. The mean duration of CAN treatment was 38.70 (±18.20) months. 18.8% of patients discontinued treatment (after a mean duration of 13.64 [±15.62] months), of which 53.2% due to lack of efficacy and 11.1% due to remission, both by the investigators’ clinical judgement. A median CAN dose of 162.73 mg (±32.00) (FMF), 166.13 mg (±61.37) (TRAPS), 169.23 mg (±47.11) (HIDS/MKD) and 293.15 mg (±90.41) (SJIA), per CAN administration, was used. The mean interval between consecutive CAN administrations was 37.79 (±27.27) days. There were no adverse events, nor serious adverse events reported.

Conclusion: In this Belgian cohort and during this observational period, most patients who received CAN suffered from FMF and only a small number suffered from TRAPS, HIDS/MKD and SJIA. From an epidemiological point of view, a higher number of cases with SJIA could be expected. The reimbursement criteria could have limited the number of patients receiving CAN. Only few patients (10.4% of total cohort) discontinued due to lack of efficacy and 2.1% (of total cohort) due to remission (both physician’s judgement). CAN was initiated rather late in life (at mean 34.6 years) even though these syndromes mostly strike in childhood or young adulthood. Dosing overall was in line with the CAN Summary of Product Characteristics (SmPC). Weight-based dosing patterns, which is advised by the CAN SmPC < 40 kg of body weight, could not be evaluated since for most patients, body weight data were missing. The mean interval among doses was slightly longer than the 4-weeks interval in the label. Treatment patterns were close to the SmPC for most of the CAN patients in this cohort in Belgium. No (serious) adverse events were reported.

REFERENCES: NIL.

Acknowledgements: NIL.

Disclosure of Interests: Michel Moutschen: None declared, Hilde Rabijns Employee of Novartis, Carine Wouters: None declared.