MANCHESTER, England -- Response to rituximab (Rituxan) remains highly variable among patients with systemic lupus erythematosus, data from a national multicenter registry showed.
At 3 and 6 months after a single treatment with rituximab, 58.75% and 48.75% of patients had improved according to the British Isles Lupus Assessment Group (BILAG) 2004 Index, yet at those same time points, 20% and 22.5% continued to have persistent active disease, reported , of the Center for Musculoskeletal Research at the University of Manchester.
Moreover, 15% and 20% experienced deterioration at 3 and 6 months, respectively, most often because of musculoskeletal flares, she reported at the here.
The published efficacy data for rituximab in lupus have shown conflicting results. In one study, , of patients with moderate to severely active extra-renal lupus, no differences were seen between rituximab and placebo, while in another study, , no benefits were seen for rituximab in patients with active proliferative lupus nephritis.
Yet in an open-label single-center study by , of University College London, whose center has been experienced in the use of rituximab for lupus, remission was seen in 42% of patients.
There may be various reasons for these conflicting data, including the heterogeneity of lupus itself and differences in study design. Therefore, Sutton and colleagues analyzed data from a national prospective biologics registry (BILAG-BR), which was established to evaluate the efficacy of biologic treatments in lupus throughout the U.K.
Participating centers responded to questionnaires about individual patients' disease duration, medications, comorbidities, and risk factors for infection.
Disease activity was assessed using the BILAG 2004 Index and the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) at baseline and at 3 and 6 months.
The analysis included 80 patients who were treated with the B-cell depleting biologic.
Almost two-thirds of patients were white. Median age was 39.5 years and median disease duration was 5.7 years.
Prednisone dose at baseline was 10 mg/day, and participants had previously used a mean of two conventional immunosuppressants. Their baseline SLEDAI-2K score was 8.
The most commonly involved BILAG systems were mucocutaneous, in 41.25%, renal in 35%, and musculoskeletal in 31%.
Improvement on the BILAG 2004 Index was defined as all category A scores (acute or progressive symptoms in an organ system) decreasing to categories B, C, or D (mild, reversible, resolved). Persistent active disease was defined as any category A score or two B scores not having resolved, and deterioration was any B, C, or D category worsening to A or any C or D category worsening to B.
At month 3, 70% of patients showed improvement on the SLEDAI-2K, 18.75% showed persistence, and 11.25% had worsening. At 6 months, the numbers were 70%, 16.25%, and 13.75%, respectively.
There was a trend towards the median prednisone dose decreasing over time, from 10 mg/day at 3 months to 8.5 mg at 6 months.
"Further analysis will be needed to identify predictors of response in these patients," she said. Unanswered questions include dosage, whether repeat infusions are beneficial, and whether cyclophosphamide should be given in combination with rituximab.
Limitations of the study included its unblinded design, small numbers, and a lack of information about concomitant medication, but a strength was its reliance on real-world data.
Disclosures
Sutton disclosed financial relationships with Roche, GlaxoSmithKline, and one co-author reported relationships with Genentech, GlaxoSmithKline, MedImmune Merck, Parexal, Roche, and UCB.
Primary Source
British Society for Rheumatology
Source Reference: Sutton E, et al "Response to rituximab in patients with refractory systemic lupus erythematosus: results from a national multicenter register" BSR 2015; Abstract 015.