Background/Purpose: Systemic Juvenile Idiopathic Arthritis (SJIA) is the most acute and severe form of JIA. Despite the substantial evidence supporting the effectiveness of biologic drugs in the treatment of SJIA, the clinical response has not been largely investigated in Turkey. Macrophage activation syndrome (MAS) is a complication that often occurs during SJIA and associated with mortality.

TURSIS, the 24-month, multi-center, retrospective, non-interventional study aimed to assess the clinical response to biological treatments for SJIA and provide real life data to improve disease outcomes.

Methods: This was a retrospective, multi-center study in patients with SJIA for whom a biological treatment had been initiated. This real-life study is based on secondary data collection from medical records of patients evaluated at the 8 Pediatric Rheumathology Clinics in Turkey (Mar 2013-Dec 2018). Patients’ characteristics, clinical inactivity, safety related variables, and ACR70 response were assessed.

Results: The study population (147 patients) consisted of 76 females (51.7%).

During the 2-year study period, 51.0% of patients (n=75) remained on the same biologic. 62 patients (42.2%) had experienced 1 switch in biological drug, and 10 patients (6.8%) switched twice.

32 patients (22.4%) had experienced a MAS attack between the diagnosis of SJIA and baseline (median 5 months). Most of the patients (81.3%) had experienced a single MAS attack; the highest number of MAS attacks per patient was 4. The frequent clinical signs of MAS were persistent fever (93.8%) and rash (81.3%). The frequencies of other clinical findings such as lung and CNS involvement, seizures and encephalopathy were lower during MAS attacks. Available data about the laboratory findings associated with MAS (n=32) revealed that hyperferritinemia was the most observed finding (96.9%) followed by a decrease in Hb level (84.4%) and an increase in LDH level (71.9%). Increased liver function tests (65.6%), hypofibrinogenemia (56.3%), hypoalbuminemia (62.5%), decrease in ESR (59.4%) and hemophagocytosis (53.1%) were the other laboratory findings observed in more than half of the patients with MAS. Nine patients experienced MAS after baseline during study period. MAS attack was not observed in any patient 12 months after the initiation of biological therapy.

At Month 3, 73.5% of patients were clinically inactive. ACR30, 50 and 70 responses could be achieved in 95.5%, 50% and 45.5% of patients, respectively.

Conclusion: This study described the patient characteristics and the impact of biological drugs on disease activity in a real-life study of patients with SJIA in Turkey. Overall biological therapies resulted in improvement in clinical activity early after initiation. There was a decrease in the frequency of MAS after initiation of biological drugs compared with time to initiation of biologic therapy. Biological drugs were generally well tolerated. Further studies can reveal the differences between the biological drugs on disease outcomes and guide treatment decisions, thereby improving patient management.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/macrophage-activating-syndrome-in-patients-with-systemic-juvenile-idiopathic-arthritis-treated-with-biological-drugs/