Background It is generally accepted that in AA amyloidosis patients with rheumatoid arthritis the renal function deteriorates gradually and finally most of the patients will receive hemodialysis in five years, even the disease activity is in good control. In recent years, several biologics including tocilizumab were found effective for rheumatoid arthritis. However, the effect of biologics therapy on renal insufficiency is not clarified. The main focus of the present study is to compare the effect of tocilizumab and oral medicines on clinical course of the renal function of AA amyloidosis patients with severe renal insufficiency.
Objectives At present, the effective therapy for preventing introducing hemodialysis in AA amyloidosis with severe renal insufficiency is quite uncertain. In the present study, we examined the effects of tocilizumab on renal function and preventing introducing hemodialysis in these patients.
Methods RA patients with amyloidosis who had high disease activity and renal dysfunction (creatinine >2mg/dl) were enrolled. The patients were separated into two groups: group 1, treated with prednisolone and low dose of methotrexate, group 2, tocilizumab alone. The patients of group 2 received only tocilizumab in every 4 weeks and did not have prednisolone nor methotrexate. We followed up for more than three years prospectively. In those patients who had obtained DAS28 remission, we compared the clinical course of renal function and the disease activity between two groups. We stopped the following-up when the patients were introduced hemodialysis.
Results Total of 14 patients was enrolled in the present study. The mean creatinine levels of the group 1 patients and the group 2 patients were 3.1 and 3.3 mg/dl respectively at the entry. The mean CRP levels of the group 1 patients and the group 2 patients were 3.2 and 3.5 mg/dl respectively at the entry. After treated with either oral medicine or tocilizumab, the levels of CRP were decreased to normal levels in less than one year and DAS28 were improved significantly in both groups. The renal functions of group 1 patients were deteriorated rapidly and were introduced hemodialysis in 2.5 years. However, the patients of group 2 did not progress renal insufficiency rapidly and were not introduced hemodialysis for more than three years. The mean negative slope of inverse-creatinine became gentle by tocilizumab therapy as shown in figure.
Conclusions Tocilizumab makes negative slope of inverse-creatinine gentle and preventing introducing hemodialysis in AA patients with severe renal insufficiency, suggesting that we should use tocilizumab in these patients.
Disclosure of Interest None declared