Background For active rheumatoid arthritis patients with inadequate response to synthetic DMARDs, biologic agents, TNF inhibitor and IL-6 receptor inhibitor, are indicated. The injection doses of biologics are scheduled per body such as etanercept and adalimumab are used more frequently than those are scheduled per kg (body weight) infusion such as infliximab and tocilizumab (TCZ). Moreover, the remains of infliximab and tocilizumab must be discarded, which makes more expensive and troublesome.
Objectives TCZ is one of useful biologics, but the dose of infusion is scheduled 8mg/kg (1), which makes the use of TCZ reluctant both technologically and financially. The present study is carried out to clarify that one vial (400mg) of TCZ infusion per body (body weight >50kg) is effective in the patients with active rheumatoid arthritis.
Methods The patients who showed inadequate response to DMARDs and biologics other than TCZ and whose body weight was between 50 to 100kg were enrolled in the present study. In addition to oral medicines, the patients were infused one vial (400mg) per body infusion of tocilizumab in every 4 weeks (OVIBOTO study). The clinical assessments and blood tests were also carried out in every 4 weeks. The patients who showed inadequate response to biologics received one vial (400mg) of TCZ instead of the biologics. To the patients who did not achieve clinical remission by one vial (400mg) of TCZ, prednisolone (PSL) and/or methotrexate were added. The patients who achieved clinical remission in 12 months were estimated as responder and others were as non-responders. To the patients who achieved clinical remission, we tapered the dose of PSL and/or DMARDs. We followed up the patients at least for 5 years.
Results Total of 102 patients was enrolled in the present study. Male and female were 24 and 78 respectively. Sixty-eight % of the patients achieved good response, 21% of patients achieved moderate response and 11% of the patients were non-responders. The body weight of the patients enrolled was between 92 to 50 kg and the mean body weight of responders and non-responders did not differ significantly. After the clinical remission was achieved, PSL and/or DMARDs were decreased. In five years, more than 10 patients were treated TCZ alone without any oral medicines for rheumatoid arthritis and kept the condition more than 4 years. The rest of responders received either or both PSL (1 to 7.5 mg) and MTX (2 to 8mg). To the patients who could not achieve clinical remission, dose escalation of TCZ was not attempted in the present study. Severe adverse events including tuberculosis and death were not found. The frequency of other adverse events of one vial (400mg) of TCZ was less than those of 8mg/kg (body weight) infusion.
Conclusions We provide evidence that one vial (400mg) of TCZ infusion is effective in active rheumatoid arthritis patients whose body weight is over 50 kg. The finding of OVIBOTO study is quite useful for taking care of active rheumatoid arthritis patients both financially and technically.
Nishimoto N et.al. Study of active controlled monotherapy used for rheumatoid arthritis, an IL-6 inhibitor (SAMURAI): evidence of clinical and radiographic benefit from an x ray reader-blinded randomised controlled trial of tocilizumab. Ann Rheum Dis 2007;66:1162-7
Disclosure of Interest None declared