Tocilizumab treatment in refractory polyarteritis nodosa: a case report and review of the literature

Polyarteritis nodosa (PAN) is a rare systemic vasculitis affecting multiple organs. Current standard treatment includes the use of glucocorticoids and cyclophosphamide. Unfortunately, some patients do not respond to this treatment and other therapeutic options are needed. We present a case of a young male with refractory PAN and ongoing biopsy evidence of active vasculitis despite optimal standard therapies, who was successfully treated with interleukin-6 antagonist, tocilizumab. A 24-year-old male presented with severe immobilizing polyneuropathy and myalgias. Clinical features included fasciitis, tenosynovitis, early signs of polyneuropathy, and panniculitis, which were largely refractory to the standard therapies. The previous unsuccessful treatments included high-dose glucocorticoids, methotrexate, cyclophosphamide, rituximab, anakinra, and intravenous immunoglobulins. Magnetic resonance imaging showed signs of myositis, with muscle biopsy confirming the diagnosis of PAN. Rapid clinical improvement and sustained remission occurred after interleukin-6 inhibition with tocilizumab at increased dose of 800mg every 4 weeks. The used search strategy identified 20 publications of which four articles were included for the further analysis. In total, we report the clinical outcome of five PAN cases from the literature and the present one. The present case and the systematic review of literature suggest that tocilizumab is a possible treatment option for, otherwise, refractory hepatitis B virus negative PAN. Randomized-controlled trials are required to evaluate the safety and efficacy of tocilizumab in PAN.