Belimumab has demonstrated efficacy, safety, and tolerability among individuals with systemic lupus erythematosus (SLE) through 13 years of treatment, according to a study recently published in Arthritis & Rheumatology.

This open-label, multicenter, continuation study (ClinicalTrials.gov identifier: NCT00583362) included 96 out of the 476 (32.2%) participants in the parent study, all of whom had SLE. Intravenous belimumab was administered once per month with SLE therapy. Following the first dose, participants were monitored for laboratory data parameters and adverse events until 24 weeks following the last dose. Assessments of efficacy were conducted every 16 weeks, including the use of corticosteroids, flares, and the SLE Responder Index (SRI). Testing included antidrug antibody, immunoglobulins, routine urinalysis, chemistry, and hematology tests, which were conducted every 8 weeks.

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The maximum length of belimumab treatment was 13 years, with a median of 3334 days, yielding a total exposure of 2294 patient-years with 115.5 median infusions. Adverse events either decreased or remained steady throughout the study period, with the most frequent being arthralgia (29.3 per 100 patient-years), upper respiratory tract infection (29 per 100 patient-years), urinary tract infection (16.2 per 100 patient-years), headache (15 per 100 patient-years), and sinusitis (16.9 per 100 patient-years). There were 237 events of depression, with a rate of 9.8 per 100 patient-years. Both infection rates and immunoglobulin G levels remained normal for most participants. At the start of the study, 32.8% of participants achieved an SRI response; this number increased to 75.6% at the end of the study. Those who used at least 7.5 mg daily of corticosteroids at baseline experienced a decrease in usage.

Limitations to this study included an open-label design, a lack of a placebo-controlled group, and varied therapies. This limits the ability to confidently attribute the results to belimumab.

The study researchers conclude that this ” is the longest study of belimumab to date, with a high percentage of patients receiving treatment for over 10 years. This study provides further safety and efficacy data consistent with the [phase 3] long-term extension studies. It will be important to investigate the effects of stopping belimumab in patients who have achieved stable, long-term low-level disease activity.”

This study received funding from GlaxoSmithKline and Human Genome Sciences. Several authors report associations with pharmaceutical companies, including those funding the study. For a full list of author disclosures, please see the original article.

Reference

Wallace DJ, Ginzler EM, Merrill JT, et al. Safety and efficacy of belimumab plus standard therapy for up to 13 years in patients with systemic lupus erythematosus [published online February 16, 2019]. Arthritis Rheumatol. doi:10.1002/art.40861