Background/Purpose: Belimumab (Benlysta) is a human monoclonal antibody that inhibits soluble B-lymphocyte stimulator. It was approved by the FDA in 2011 for treatment of active, autoantibody-positive, systemic lupus erythematosus (SLE) in adults. Patients with pediatric-onset SLE (pSLE) have more severe disease requiring more aggressive immunosuppression than adult SLE. To date, there have been no published data on the use of belimumab in pSLE.

Methods: Observational study of patients with SLE diagnosed before their 19^thbirthday, and treated with belimumab, from 10 large academic centers. Data were collected on demographic and disease characteristics, clinical manifestations requiring treatment, concomitant medications, disease course, and treatment outcomes. The outcome was defined as the physician’s impression of improvement in the initial manifestation(s) being treated without worsening in other organ systems. Chi-square and Student t-tests were used when appropriate.

Results: Of a cohort of 195 patients treated with belimumab, 38 patients had pSLE. The median age at diagnosis was 13.5 years old (range 4-18 years old); the median disease duration at initiation of belimumab was 12.5 years (range 2-43 years). Eighty-nine percent of the patients were female, 39% Black, 39% Caucasian, 11% Hispanic, 5% Asian. All patients were taking other background medications prior to initiation of belimumab (hydroxychloroquine 92%, prednisone 89% compared to 73% in the adult SLE patients, p=0.005, mycophenolate mofetil 47%, azathioprine 21%). The most common indications for initiation of therapy were inability to taper steroids (89%, mean prednisone equivalent dose 17.2mg/day compared to 27% in the adult SLE patients, p<0.0001), arthritis (61%), and rash (39%), accompanied by worsening serologic activity (increasing anti-dsDNA and hypocomplementemia). At 6 months, 71% of pSLE patients had responded clinically to belimumab compared to 48% of the entire patient population (p=0.01), and exhibited improvement in their laboratory abnormalities. Steroids were tapered in 63% of pSLE patients, and discontinued in 22%. Six months after initiation of belimumab, pSLE patients who responded clinically demonstrated an 86% decrease in anti-dsDNA (p<0.0001), 15% increase in C3 (p=NS), and 27% increase in C4 (p=NS).  Of note, 100% of blacks with pSLE responded clinically (p=0.0003) with improvement in all serologic markers. Thirty-two of 38 pSLE patients tolerated infusions well, with only 6 patients discontinuing treatment.

Conclusion: This is the first study investigating the use of belimumab in pSLE. Our data demonstrate favorable clinical and laboratory outcomes across all ethnic groups: 71% of patients responded clinically within 6 months and steroids were tapered in 63% of our patients, suggesting a more important role for belimumab in pediatric-onset SLE.

---

« Back to 2014 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/favorable-response-to-belimumab-in-pediatric-onset-systemic-lupus-erythematosus/