¹ Udari Guruge, ¹Duminda Abeysinghe

¹Rheumatology and Rehabilitation Hospital

Purpose Statement: Introduction

Takayasu Arteritis (TAK) targets large vessels, particularly the aorta and its main branches. Roughly 50% of individuals with TAK either don’t respond well to steroids or face disease recurrence, making it necessary to incorporate additional immunosuppressants to reach remission.

Here we present three cases from Sri Lanka of refractory TAK successfully managed with Tocilizumab.

Method(s): Case Histories

Case 1

A 19-year-old patient was presented with fever and left arm claudication for 2 months. On examination brachial and radial pulse volume was lower in left. Blood pressure was asymmetrical, and a bruit was heard over the left carotid artery. His ESR and CRP were high. CT Aortogram showed left subclavian stenosis. Treatment consisted of high dose prednisolone (1mg/kg/day) and Methotrexate (MTX) 15mg/weekly. As he developed MTX induced transaminitis it was changed to Mycophenolate Mofetil (MMF) 1g bd. However, the patient relapsed while tapering prednisone and was unable to reduce the dose to <15 mg/day despite being on MMF. His Upper limb claudication recurred with a new right Subclavian Bruit. Repeat CT Aortogram showed right Subclavian and axillary artery stenosis and tortuous focal dilatation of the right common carotid artery indicating Major relapse. Monthly Tocilizumab was therefore started and allowed complete clinical and biological remission of disease.

Case 2

16-year-old female presented with neck pain and fever for 6 weeks. Examination revealed left carotid bruit. CT Aortogram showed circumferential mural thickening of aortic arch, descending aorta up to renal arteries, brachiocephalic and left common carotid arteries. Treatment with 60mg/day prednisone and 10 mg/week MTX was started. Despite the initial good response, she developed MTX induced transaminitis, leading to a switch to MMF(1gbd). Three months later, she experienced a clinical relapse with elevation of inflammatory markers necessitating treatment with monthly Tocilizumab. After receiving two doses, she became asymptomatic, and inflammatory markers returned to baseline.

Case 3

A 31-year-old female presented with a history of low-grade fever and constitutional symptoms for 6 months. Physical examination revealed right subclavian and carotid bruits. Her inflammatory markers were high. Doppler ultrasound of neck showed a stenosis of right subclavian and carotid arteries. MRI confirmed the presence of diffuse aortitis. Subsequently she commenced prednisolone 50 mg/day and MTX 15 mg/week. Despite continuation of immunosuppressants her inflammatory markers and disease activity remained high. Therefore, Tocilizumab was added which led to complete biological and radiological response with prednisolone being able to tail off.

Result(s): Discussion

The mechanism of action of tocilizumab, targeting the interleukin-6 (IL-6) pathway, aligns with the understanding of TAK pathogenesis, where IL-6 plays a crucial role in promoting vascular inflammation and injury. By inhibiting this pathway, tocilizumab can effectively mitigate the inflammatory cascade underlying TAK, leading to disease improvement.

Conclusion(s): This case series highlights the ability of Tocilizumab to induce rapid clinical and biological improvements, along with its steroid-sparing effect, which makes it a promising choice, especially in patients with refractory disease.