Background/Purpose: Belimumab, a B-lymphocyte stimulator, was FDA-approved March 2011 for the treatment of adult patients with active, autoantibody-positive SLE receiving standard of care (SOC) medications. Using data from a large, privately-insured US administrative claims database, we sought to identify and characterize a cohort of SLE patients who initiated belimumab treatment.

Methods: A retrospective cohort analysis was conducted in the US Truven Health MarketScan® Commercial Claims and Encounters Database (study ID 204489). Patients were aged 18-64 years at first belimumab infusion (index date) during the study period (2010 – end of available 2014 data). SLE diagnosis was based on ICD-9 code 710.0 documented prior to/on index date. We included patients with complete medical and pharmacy benefits ≥6 months prior to and ≥12 months after the index date. Demographic and clinical characteristics, SOC medication use, healthcare utilization and estimates of SLE disease and flare severity during the 6 month pre-index period were evaluated. Belimumab discontinuation was defined as ≥84 day gap in infusions.

Results: N=762 patients met the inclusion criteria. Mean age at index date was 44 years (SD 11) and 94% were female.  Pre-index period diagnosed co-morbidities included musculoskeletal (67%), cardiovascular (41%), central nervous system (39%), mucocutaneous (27%), hematologic (22%) and lupus nephritis (7%) disease. Medications prescribed in the pre-index period included oral corticosteroids (73%), antimalarials (66%), immunosuppressants (60%) and NSAIDs (30%); not mutually exclusive. In the pre-index period, ~80% of patients were prescribed ≥2 SOC medications (excluding NSAIDs), and the mean prednisone-equivalent dosage for the cohort was 7.3 mg/day (SD 13.7); 34% had a mean prednisone-equivalent dose ≥7.5 mg/day. Healthcare utilization in the 6-month pre-index period included ≥1 inpatient visit (12%), emergency department visit (28%) and outpatient procedure (47%) or laboratory test (48%). A disease severity algorithm estimated mild, moderate, and severe disease in the pre-index period for 32%, 55%, and 13% of patients, respectively. Ninety-four percent experienced ≥1 flare in the pre-index period, with the most severe flare classified as mild (17%), moderate (71%) and severe (12%). Mean number of belimumab infusions in the post-index period was 12 (SD 9), with mean 11 months of belimumab use (SD 9). Belimumab was discontinued by 25% of patients during the ≥12-month post-index period, and 60% of patients received belimumab for ≥6 months.

Conclusion: In this large sample of belimumab treatment initiators, there was a high frequency of oral corticosteroid/immunosuppressant use in the 6 months prior to initiating belimumab treatment. Polytherapy was the norm, but ~20% were on either one medication or none. Prior to belimumab treatment, most patients had moderate to severe disease, and nearly all experienced ≥1 flare. More than 50% of patients continued belimumab treatment for ≥6 months. Reasons for discontinuation were not ascertainable in this data source, and future analyses are planned to assess the comparative effectiveness of adding belimumab to SOC treatment.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/characteristics-of-patients-diagnosed-with-systemic-lupus-erythematosus-sle-initiating-treatment-with-belimumab-in-a-us-commercially-insured-database-2010-2014/