Organ damage in patients treated with belimumab versus standard of care: a propensity score-matched comparative analysis

Abstract

Objectives: The study (206347) compared organ damage progression in patients with systemic lupus erythematosus (SLE) who received belimumab in the BLISS long-term extension (LTE) study with propensity score (PS)-matched patients treated with standard of care (SoC) from the Toronto Lupus Cohort (TLC).

Methods: A systematic literature review identified 17 known predictors of organ damage to calculate a PS for each patient. Patients from the BLISS LTE and the TLC were PS matched posthoc 1:1 based on their PS (±calliper). The primary endpoint was difference in change in Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) score from baseline to 5 years.

Results: For the 5- year analysis, of 567 (BLISS LTE n=195; TLC n=372) patients, 99 from each cohort were 1:1 PS matched. Change in SDI score at Year 5 was significantly lower for patients treated with belimumab compared with SoC (-0.434; 95% CI -0.667 to -0.201; p<0.001). For the time to organ damage progression analysis (≥1 year follow-up), the sample included 965 (BLISS LTE n=259; TLC n=706) patients, of whom 179 from each cohort were PS-matched. Patients receiving belimumab were 61% less likely to progress to a higher SDI score over any given year compared with patients treated with SoC (HR 0.391; 95% CI 0.253 to 0.605; p<0.001). Among the SDI score increases, the proportion of increases ≥2 was greater in the SoC group compared with the belimumab group.

Conclusions: PS-matched patients receiving belimumab had significantly less organ damage progression compared with patients receiving SoC.

Keywords: disease activity; systemic lupus erythematosus; treatment.

Figure 1

Study design and visit* assessments. *For the BLISS LTE study, the final visit in the parent study of the BLISS LTE study was recorded at 76 weeks. Thereafter, SDI was recorded every 48 weeks (‘annual’ visits). In the TLC, annual visits were defined as the visit closest to each 48-week interval from baseline that deviated by no more than 24 weeks from that interval. **Patients within the TLC had no exposure to belimumab as it was not available at the time. LTE, long-term extension; SDI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index; SLE, systemic lupus erythematosus; SLEDAI, SLE Disease Activity Index; SoC, standard of care; TLC, Toronto Lupus Cohort.

Figure 2

Predictors, variables and operationalised variables determined from a systematic literature review and used within the PSM analysis. *The variable ‘disease activity over time’ could not be used within the PSM as it was not a baseline variable. **The references for the ‘race/ethnicity’ variable and the ‘baseline SDI’ variable were ‘Caucasian’ and ‘Baseline SDI=0’, respectively. ACR, American College of Rheumatology; PSM, propensity score-matched; SDI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index; SF-20, 20-item short form survey; SLE, systemic lupus erythematosus; SLEDAI, SLE Disease Activity Index.

Figure 3

Difference in time to organ damage progression in patients with ≥1 year of follow-up.*Years are 48 weeks in length. KM, Kaplan-Meier; SLE, systemic lupus erythematosus; SoC, standard of care.