Anti-cytokine therapy is reportedly useful in amyloid A (AA) amyloidosis complicating rheumatic diseases. However, to date no studies have directly compared the utility of tumour necrosis factor (TNF) inhibition to that of interleukin-6. The aim of our retrospective study was to compare the clinical utility of tocilizumab (TCZ) and anti-TNF (TNF inhibitor) therapy.
We studied 42 patients treated with anti-cytokine agents at our hospital: 31 had received a single agent, ten had received two agents and one had received three agents. Patients were divided into a TCZ group (22 patients) and a TNF inhibitor group (32 patients). The main parameters compared were treatment retention rate, serum amyloid A (SAA) profile, renal function profile and clinical disease activity index.
The 5-year retention rates were 90.4 (TCZ group) and 34.3 % (TNF inhibitor group) (p = 0.0154, log-rank test). The median SAA fell from 219.2 μg/mL at treatment initiation to 5.0 μg/mL at last observation (TCZ), and from 143.6 to 38.1 μg/mL (TNF inhibitor) (p = 0.0194). Estimated glomerular filtration rate was improved in 72.7 (TCZ) and 34.4 % (TNF inhibitor) of patients (p = 0.0062). The rates of clinical remission or low disease activity at last observation for the TCZ and TNF inhibitor groups were 72.7 and 40.7 % (p = 0.0201), respectively.
Based on these results, we conclude that TCZ was of greater clinical utility than anti-TNF therapy in our patients with AA amyloidosis complicating rheumatic diseases.