E67 Still's disease in children refractory to usual treatments: recourse to biotherapies: challenges and opportunities
Authors: Gacem O , Ouahbi K , Mehaba N , Ayad N , Guers S , Mansouri N , Ladj M S 
Published: August 2023

Abstract

Background
Still's disease in children is a rare autoinflammatory disease with distinct characteristics from other forms of Juvenile Idiopathic Arthritis. A better understanding of its mechanism has led to the use of targeted therapies with a significant improvement in patient prognosis. Despite these advances, there are still subtypes of Still's disease refractory to the usual treatments with serious complications.

Objective
demonstrate therapeutic escalation in the Child’s Still

Methods
We report the case of a patient unresponsive to multiple disease-modifying antirheumatic drugs (DMARDs), who required high doses of steroids. The biological ones were an inevitable recourse to improve the vital and functional prognosis; with at the end, a therapeutic escape with anti IL1 after two years of favorable response.

Case report
12-year-old girl with no particular family history, with Still's disease diagnosed at the age of nine with a typical clinical form: thermal steeple concomitant with a morbiliform and evanescent skin eruption, polyarthritis, with hepatosplenomegaly. The diagnosis was confirmed by a major biological inflammatory syndrome with raise serum ferritin, serum C-reactive protein level and sedimentation rate. Despite doses &gt; 0.5 mg/kg/d of prednisone, she showed high-threshold sensitivity to corticosteroids with the appearance of deleterious effects: Cushingoid obesity, stretch marks and bilateral cataracts. Methotrexate was added at a dose of 12 m/m2/week, without clinical response. She eventually developed severe macrophage activation syndrome which was successfully treated with bolus corticosteroids. Faced with this systemic form refractory to the usual treatments; biotherapy was used. Anakinra was added to his treatment at a dose of 2 mg/kg/day. Impressive improvement in systemic and joint clinical signs occurred within the first few weeks of treatment and acute phase reactants returned to normal. Anakinra was well tolerated and no adverse effects were observed. After 24 months of follow-up and complete clinical remission, without corticosteroid therapy, she presented with a severe flare of her disease with severe inflammatory runaway (SMA) and disseminated intravascular coagulation. After controlling this acute clinical condition with intravenous corticosteroids and ciclosporin; we switched to antiIL6 with a good clinical and biological evolution.

Discussion
The excellent response to anakinra in this case refractory to conventional treatments suggests that IL1 inhibition could be an important therapeutic target in some patients. Nevertheless, some subtypes of Still's disease escape anakinra after a few years of good response and this has been suggested by some authors.

Conclusion
Pro-inflammatory cytokines such as interleukin IL1, IL6, and IL18 have been implicated in the pathogenesis of childhood Still's disease. In recent years, targeted biologics have been used with several cases of successful treatment in forms refractory to conventional drugs.