Background Rheumatoid arthritis (RA) is the most common inflammatory rheumatic disease. Tocilizumab (TCZ) is the first therapeutic agent targeting IL-6 to be effective in RA. Recent ACR/EULAR recommendations highlighted the aim to treat RA patients quickly in order to obtain a clinical remission. However, drug therapeutic strategy for patients with prolonged remission is not well defined. Some studies suggest that dose reduction or discontinuation of biological agents can be achieved in a relevant proportion of patients with RA without loss of disease control.
Objectives Our objective was to indentify predictive factors of persistent stable remission after progressive spacing infusions of TCZ in RA patients.
Methods In this single centre open label study, patients were included if they fulfilled the 1987 ACR criteria for RA and if they were in remission for at least 3 months under TCZ therapy. Remission was defined by a DAS 28 ESR <2.6, with only one swollen joint authorized (in a 28 joints count), without corticosteroids for at least 4 weeks, and a stable dose of disease modifying anti-rheumatic drugs (DMARDs) for at least 3 months.
The initial evaluation included clinical, biological and Doppler ultrasound parameters of hands and feet. Spacing pattern was fixed in advance, without changing the dose of TCZ that allowed the remission: 6 weeks spacing for the first 3 months, and if possible spacing to 8 weeks for 2 other infusions.
Statistical analyses were performed by Student and Fisher' exact tests with 95% confidence interval.
Results Fourteen patients were included from July 2011 to September 2012. Disease duration was 12.8 years 95%CI [7.2-18.5] and average age of patients was 50.3 years old (YO) 95% CI [19.9-80.7]. Six patients received concomitant treatment with methotrexate, 3 with leflunomide, and 5 received TCZ alone. Ten patients (71.4%) presented erosions at baseline and 8 (57%) were positive for rheumatoid factor (RF) and/or ACPA. Average DAS 28 at baseline was 1.59.
Five patients (35.7%) presented prolonged remission after 7 months, and 9 (64.3%) relapsed after spacing. Among these 9 patients, 4 relapsed early (before 12 weeks) and 5 later (from 3 to 7 weeks).
In the group of patients with prolonged remission, the average age was 44.4 YO against 53.6 YO in the “relapse” group (not significant). The mean duration of the disease was respectively 7.6 and 15.7 years in these two groups (not significant).
All relapsed patients had erosive RA, against only 1 (20%) in prolonged remission group (p=0.005). Seven patients who relapsed (78%) were RF positive, against only 1 patient (20%) in persistent remission (p=0.09). This result was the same for ACPA.
We found no difference between the 2 groups for treatment duration before spacing, association with a DMARD, and presence of hyperaemia in Doppler-ultrasound at baseline.
Conclusions Spacing TCZ infusions seems possible for patients with prolonged remission. Our study suggests that it would be useful to propose this strategy to patients without disease severity factors, especially erosions. However, according to the limited number of patients, broader analyses on a larger cohort are now needed to confirm our results.
Disclosure of Interest None declared