Background Intravenous tocilizumab has been used since 2009 in Europe for the treatment of active rheumatoid arthritis. Since 2015, a subcutaneous formulation is available. The switch from a monthly, intravenous, with dose adjusted for bodyweight treatment to a weekly, subcutaneous, fixed dose, leads to various questions about efficacy and toxicity.
Objectives The objectives were to evaluate the efficacy maintenance (maintenance rate and DAS28 variation), the safety, the dose variation after the switch and the characteristics of patients switching to the subcutaneous form respect to those following with the intravenous tocilizumab.
Methods Multicenter and retrospective study was performed from a cohort of 203 patients undergoing intravenous tocilizumab from the rheumatology unit of 7 university hospitals between September 2015 and May 2016. Assessment has been done on the records, effectiveness was assessed using the DAS28, adverse events and reasons for staying on IV form were reported.
Results On the 203 records analyzed, 3 were secondarily excluded. Of the 200 patients, 77 have switched for the subcutaneous form. Mean age of the 200 patients was 58 years (+/- 13.3) with 155 women (78%) and the mean duration of rheumatoid arthritis was 14 years (+/- 10.4). 72% of patients received a standard intravenous dose (8mg/kg/month) at baseline.
At the first visit after the prescription of the subcutaneous treatment, 58 patients on 65 (89%) maintained the treatment. The mean DAS28 was 1.53 (+/-1.00) at baseline and 1.19 (+/-0.78) at T1 (45 patients). Three patients received a reduced subcutaneous dose of 162mg/2 weeks following a reduced IV dose (<8 mg/kg/month) and maintained the subcutaneous treatment.
About safety, there was no new case of neutropenia<1000/mm3. One severe adverse effect occurred (gastro intestinal perforation).
Regard to the dose variation, for the 77 patients switching, the mean difference between intravenous and subcutaneous dose was + 29mg/week (+/-35mg) with the subcutaneous tocilizumab.
Reasons for staying on IV form were essentially: the subcutaneous tocilizumab was not proposed in 55% of the cases and 17% of patients refused the subcutaneous form.
Conclusions 89% of patients maintained the subcutaneous treatment after 4 months; efficacy was maintained in patients who received a reduced subcutaneous dose. Despite the higher dose after the switch (+29mg/week), there was no new case of neutropenia.
Disclosure of Interest None declared