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 three 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 two 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 two 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 two 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 two 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.