Single Patient Study to Treat Relapsing Polychondritis With Tocilizumab

Overview

Relapsing polychondritis (RP) is a rare, immune-mediated disease associated with inflammation in cartilaginous structures and other tissues throughout the body. Prognosis can be poor, especially in cases where there is acute involvement of the laryngotracheal cartilages leading to airway destruction, which are resistant to treatments such as corticosteroids, immunosuppressive or cytotoxic drugs. The pathogenesis remains unclear although it is thought that autoimmune reactions to antigens present in cartilages, such as type II collagen and matrilin may evoke symptoms. There are no known clinical or laboratory measures that predict the expression of specific disease manifestations or the overall disease course. Two recently published case reports have shown an association with elevated serum IL-6 levels and relapsing polychondritis. In these case reports, both patients with refractory relapsing polychondritis were treated with tocilizumab, a humanized monoclonal antibody to the Interleukin 6 receptor, and achieved sustained response to the drug. This single patient trial aims to evaluate the response to Tocilizumab in an eight year old boy with relapsing polychondritis who has been shown to have elevated serum IL-6 levels and who has responded poorly to conventional therapies. The study hypothesis is that Tocilizumab will be able to control the disease in this patient.

In this N = 1 study a single known patient with relapsing polychondritis who has failed methotrexate, various anti TNF medications, anti IL1 medication and prolongued glucocorticosteroids will be recruited to receive Tocilizumab 8 mg /kg q 2 weeks iv. The objective is to assess efficacy of tociliuzmab in combination with stable ongoing therapy. Our patient received tocilizumab 8 mg/kg over 1 hour by intravenous infusion every 2 weeks throughout the course of the study. To assess tocilizumab efficacy, the primary objective is the change in physician global assessment on a 100-mm horizontal visual analogue scale (VAS) of disease activity. The secondary objectives were the change in parent global assessment of disease activity on a 100 mm VAS and the glucocorticoid dose in mg per day. Frequency of adverse events was also measured at baseline and after each biweekly tocilizumab infusion.