Weight change during pharmacological blockade of interleukin-6 or tumor necrosis factor-α in patients with inflammatory rheumatic disorders: a 16-week comparative study.

BACKGROUND: Interleukin (IL)-6 -/- mice develop spontaneous mature onset obesity, while the influence of the pharmacological blockade of IL-6 on body weight in humans has not been previously reported. The aim of the present study was to observe weight change in patients treated with tocilizumab (TCZ). METHODS: Twenty-one consecutive patients who started new treatment with TCZ were enrolled in the study. Sixteen consecutive patients who started treatment with infliximab (IFX) formed the control group. Height and weight of all patients were registered and Body Mass Index (BMI) calculated before the first treatment and at week 16. The Mann-Whitney or paired Wilcoxon test were used for comparisons between or within groups, respectively. RESULTS: The study demonstrated that treatment with TCZ was accompanied with significant weight gain and BMI increase (p=0.04), while IFX treatment did not result in any significant weight change during the 16-week period. CONCLUSIONS: Weight gain can be seen in some patients during the pharmacological blockade of IL-6. The phenomenon and metabolic pathways involved should be further investigated.