346 Clinical Effects of Tocilizumab, a Humanized Anti-interleukin-6 Receptor Antibody, on Patients with Autoimmune and Allergic Diseases

BACKGROUND: A humanized anti-interleukin-6 receptor, tocilizumab, has been approved as a biological drug for the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis and Castleman's disease. Since dysregulation of IL-6 production also plays a pathologic role in other various autoimmune and allergic diseases, we tested whether tocilizumab might have beneficial effect on refractory autoimmune or allergic diseases to conventional treatment regimens. METHODS: After informed consent by patients and approval by the Ethics Committee of Osaka University Hospital were obtained, patients were treated with tocilizumab at 8 mg/kg every 4 weeks. RESULTS: The diseases for which off-label use of tocililizumab was performed included amyloid A amyloidosis, relapsing polychondritis, systemic sclerosis, HLA-B27 positive spondyloarthritis such as reactive arthritis and psoriatic arthritis, polymyalgia rheumatica and polymyositis. After 3 injections of tocilizumab amyloid fibril deposits in the colon disappeared in a patient with gastrointestinal AA amyloidosis, who was resistant to anti-TNF drugs and disease-modifying antirheumatic drugs. In 2 patients with refractory relapsing polychondritis, the continuous tocilizumab treatment for more than 3 years could ameliorate clinical symptoms related to upper and lower airways and stabilize the disease activity. The skin sclerosis of 2 patients with systemic sclerosis became softened with reductions of 52 and 23% in the modified Rodnan total skin score by the tocilizumab treatment. Two administrations of tocilizumab led to the disappearance of joint swelling, pain and complete resolution of symptoms in a patient with refractory reactive arthritis to several therapeutic regimens for 4 years, whereas 2 patients with severe psoriatic arthritis did hardly respond to tocilizumab. In a patient with polymyalgia rheumatica, the tocilizumab treatment caused a reduction of the disease activity score (PMR-AS) from 22.14 to 0.74, indicating remission. Creatine phosphokinase normalized by 2 patients with polymyositis who had been resistant to corticosteroids and immunosuppressive drugs, in association with the disappearance of the high intensity zones in the thigh muscles on MR images. CONCLUSIONS: These clinical effects of tocilizumab suggest that it may be an optional treatment for refractory autoimmune or allergic diseases although further clinical trails will be essential.