OP0039 Impact of Belimumab Use on Flares among Patients Diagnosed with Systemic Lupus Erythematosus (SLE) in A Us Commercially Insured Database: 2010-2014
Authors: M. Stott-Miller, P. Egger, A. Eudy, J. Maskell, Q. Fu, H. Kan, R. Alfonso-Cristancho, K. Costenbader
Journal: Annals of the Rheumatic Diseases (2016)

<h3>Background</h3> 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 medications. There is a need to evaluate belimumab9s effectiveness in real-world practice settings. <h3>Objectives</h3> To describe the effectiveness of initiating belimumab treatment on flare episodes. <h3>Methods</h3> Patients aged 18–64 years at first belimumab infusion (index date) between 01 Jan 2010 – 31 Dec 2014 were selected from the US Truven Health MarketScan® Commercial Database (study ID 204999). SLE diagnosis (ICD-9 code 710.0) was documented prior to/on index date. We included patients with complete medical and pharmacy benefits ≥6 months prior to index (baseline period). Moderate and severe SLE flare episodes were defined using previously published algorithms developed for claims data (Garris C, 2013). Incidence rates (IRs) and 95% CIs were calculated per subject for 3-month intervals, with two intervals in the baseline period and a variable number of intervals in the follow-up period. In primary “as treated” analyses, person-time spanned the duration of belimumab exposure including one month after last infusion. Sensitivity analyses were performed using “intention to treat” (ITT) analysis including all follow-up during each interval for person-time. To statistically compare the period before and after belimumab initiation, IRs were calculated in the total baseline and follow-up period per patient in both as-treated and ITT analyses, and compared using the Wilcoxon signed-rank test. <h3>Results</h3> We identified 1835 belimumab initiators (mean age 43 years, SD 11; 94% female). SLE comorbidities in the baseline period included arthritis (46%), lupus nephritis (7%), anemia (20%), rash (27%), arthralgia (43%), and mood disorders (34%). Similarly, 15% were hospitalized and 27% had ER visits. Baseline medications included antimalarials (68%), oral corticosteroids (71%), immunosuppressants (59%), and NSAIDs (32%). Belimumab continuation rates were 81% at 6 months, 55% at year 1, 35% at year 2 and 27% at year 3 post index. There was a marked and sustained decrease in moderate/severe flare incidence following belimumab initiation (Figure 1). This pattern was similar in the ITT sensitivity analysis. The Wilcoxon signed-rank test yielded highly statistically significant results for both the primary as treated analysis and the ITT analysis (p&lt;0.001). <h3>Conclusions</h3> In this large sample of SLE patients initiating belimumab, the rates of moderate/severe SLE flares during belimumab treatment were significantly lower compared with those in the pre-belimumab period. The comparative effectiveness of belimumab vs. standard of care immunosuppressants, as well as causes and effects of belimumab discontinuation should be further explored. <h3>Acknowledgement</h3> Study funded by GSK. <h3>Disclosure of Interest</h3> M. Stott-Miller Shareholder of: GSK shares, Employee of: GSK, P. Egger Shareholder of: GSK shares, Employee of: GSK, A. Eudy Employee of: GSK, J. Maskell Employee of: GSK, Q. Fu Shareholder of: GSK shares, Employee of: GSK, H. Kan Shareholder of: GSK shares, Employee of: former employee of GSK, R. Alfonso-Cristancho Shareholder of: GSK shares, Employee of: GSK, K. Costenbader: None declared