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Seropositive patients with RA more likely to respond to rituximab
Patients with rheumatoid arthritis who were seropositive for rheumatoid factor or anti-citrullinated peptide antibodies were more likely to respond to treatment with rituximab than seronegative patients, according to findings from a Finnish observational study.
Researchers studied data from 151 patients with rheumatoid arthritis (RA) treated with rituximab in a routine clinical setting between April 2005 and December 2011. Patient data collected included prior use of disease-modifying anti-rheumatic drugs (DMARDs) or biologics, comorbidities, and other factors related to the choice of rituximab therapy. Baseline C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were also measured.
Patients were predominantly female (75%) and seropositive (89%), defined as testing positive for either rheumatoid factor or anti-citrullinated peptide antibodies, or both. Most (93%) were treated with a traditional DMARD, primarily methotrexate (97%), prior to enrollment.
Increased frequency of infections, preceding malignancies, economic reasons, active or latent tuberculosis, high titer antinuclear antibodies and comorbid multiple sclerosis were cited as reasons to treat with rituximab as a first biologic in 42 patients.
Overall, 128 patients received two courses of rituximab, 76 patients received three courses and 42 patients received four courses. After the first treatment, median CRP was reduced by 19.7 mg/L from the baseline median CRP of 24 mg/L. ESR was reduced by 9 mm/h, from a baseline median of 34 mm/h.
Both median DAS 28 at baseline and after treatment were available for 113 patients. Mean DAS 28 at baseline was 5.4, compared with 3.3 after the first treatment and 3.1 after the second retreatment for 105 of those patients. Mean time to retreatment was 11 months, according to the researchers.
Two patients achieved long-term remission with a DAS 28 of less than 2.6 for at least 2 years without retreatment. Overall, median reduction in DAS 28 was 1.7 in 52 patients, 2.4 in 50 patients and 2.7 in 24 after the first, second and third courses of treatment, respectively.
Response based on the European League Against Rheumatic Diseases criteria was classified as good in 38% of patients and moderate in 44% of patients, and 18% of patients showed no response.
Thirty-one patients discontinued treatment due to lack of response; 15 of these patients discontinued after the first treatment, 12 stopped after the second treatment and four discontinued after three courses of treatment, according to the researchers.
Seronegative patients achieved significantly greater reductions in DAS 28 after the first treatment than seronegative patients. However, the researchers found a small subset of patients who were seropositive for both rheumatoid factor and anti-citrullinated peptide antibodies did not experience significant reductions in DAS 28. – by Shirley Pulawski
Disclosures: Valleala received payment from Roche for collecting study data, is a paid consultant and advisory board member for Roche, and received payment for lectures and meeting expenses from Roche. Please see the full study for a list of all other authors’ relevant financial disclosures.