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AB0959 EXCELLENT RESPONSE TO TOCILIZUMAB IN PEDIATRIC ONSET REFRACTORY TAKAYASU ARTERITIS: CASE SERIES OF THREE PATIENT

Background Takayasu arteritis (TA) is a idiopathic and rarely seen chronic systemic vasculitis that affect the aorta and its major branches. Stenosis, occlusion and aneurysms may develop in large arteries in the setting of granulomatous panarteritis (1). The first purpose in patients with TA after diagnosis is to prevent the progression of vascular lesions with medical treatment. Used as a first choise in medical treatment, steroids and steroid-sparing immunosuppressive agents, may sometimes fail to prevent to progression of the disease. Interleukin (IL)-6, which synthesize from activated dendritic cells, is one of the main cytokine in the development of panarteritis in TA. Tocilizumab (TCZ), an anti-IL-6 receptor antibody, has been shown to be used as an effective treatment in many refractory adult TA patients (2). Objectives We have presented our experience with TCZ treatment in three children with refractory TA. Methods We reviewed three cases of childhood TA diagnosed between 2016-2018. These patients were successfully treated with TCZ that started due to the refractory disease. Results The first patient, 15 year-old girl, presented with fever, headache and abdominal pain. Physical examination showed systolic murmur in interscapular area and abdominal tenderness. The C-reactive protein (CRP) level was 4.7 mg/dL (n: <0.5 mg/dL) and the erythrocyte sedimentation rate (ESR) was 78 mm/h (n: <20 mm/h). Doppler ultrasound imaging showed wall thickening in bilateral carotid arteries. The angio-CT imaging revealed that 70% stenosis in the bilaterally renal arteries and partial stenosis in the mesenteric artery. Methylprednisolone treatment was started (30 mg/kg/d x 3 days). Maintenance treatment consisted of prednisone (1 mg/kg/d), methotrexate and azathioprine. Her complaints improved rapidly and the acute phase reactants decreased. However, the patient relapsed while tapering the corticosteroid. The second patient was diagnosed with TA in 2012 after the complaint of chest pain and finding of hypertension. MRI angiography revealed wall irregularities and stenosis in the descending aorta and dilatation in the ascending aorta. CRP and ESR levels found high. The patient was followed up with glucocorticoid and azathioprine treatment. After four years of follow-up, relapse of the disease was observed with symptoms of fever, chest and back pain. The third patient presented with fever, abdominal pain, arthralgia in the left elbow and arthritis of the left knee, and was diagnosed with TA two years ago. His CRP and ESR levels were found elevated. The angio-CT imaging revealed that 70% stenosis in the 4 cm segment of the abdominal aorta, 70% stenosis in the right renal artery, 50% stenosis in the left renal artery and 90% stenosis in the origin of celiac trunk and superior mesenteric artery. Despite the given bolus methylprednisolone and methotrexate therapy, there had not seen any improvement in disease activity. Tocilizumab was started at 8 mg/kg monthly in all three patient and they achieved complete clinical and laboratory remission. Conclusion These cases demonstrate that the TCZ treatment has been shown to be a successful option in TA patients resistant to conventional immunosuppressive therapies. Disclosures The authors have declared no conflicts of interest. Informed consent form was obtained from patients and their legal guardians References [1] Mathew AJ, Goel R, Kumar S, Danda D. Childhood-onset Takayasu arteritis: an update. Int J Rheum Dis. 2016;19:116-26. [2] Goel R, Danda D, Kumar S, et al. Rapid control of disease activity by tocilizumab in 10 ’difficult-to-treat’ cases of takayasu arteritis. Int J Rheum Dis2013;16:754–61. Disclosure of Interests None declared