Background/Purpose: Despite improvements in medical care leading to improved survival, systemic lupus erythematosus (SLE) adversely affects patients’ health related quality of life (HRQoL). To explore the impact of clinical characteristics on reported HRQoL and fatigue, we performed a post hoc analysis (HO-16-17189) based on the long-term continuation study (GSK study 112233; NCT00724867) of the BLISS-76 randomized controlled trial (RCT) in the US.

Methods: In the continuation study, patients who received active drug in the RCT continued to receive the same doses of belimumab (1 or 10 mg/kg IV, every 28 days; all 10 mg/kg post-Mar 2011) plus standard of care (SoC) (belimumab/belimumab group). Patients previously receiving placebo received belimumab 10 mg/kg IV (placebo/belimumab group). HRQoL and fatigue assessments included Short Form-36v2 (SF-36) Medical Outcomes Survey and Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue. In the post hoc analyses, subgroup assessments were based on treatment (placebo/belimumab or belimumab/belimumab); responders (SLE Responder Index [SRI]-4 response within 1 year); high disease activity (high anti-dsDNA, low C3/C4); flare (SLE Flare Index); steroid dose (0 to 7.5 mg/d, ≥7.5 mg/d); damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology [SLICC] Damage Index [SDI]; 0, 1, and ≥2) at baseline (BL). Mixed-effect models were used to obtain means over time, with adjustments for disease duration and activity, BL HRQoL scores, age, gender, and race.

Results: The modified intent-to-treat population comprised 268 patients; 140 completed the continuation study. Statistically significant associations were observed between treatment groups and change from BL in SF-36 Physical (PCS) and Mental component (MCS), and FACIT scores (all p<0.01; Table). Responders and those with high disease activity reported numerically larger improvements from BL in HRQoL scores. Reported HRQoL scores were similar between all other subgroups at BL.

Conclusion: Differences in SF-36 and FACIT outcomes between treatment subgroups must be considered in light of differing BL scores: those for the placebo/belimumab arm were at time of entry into the extension study, following successful SoC treatment; whereas the belimumab/belimumab arm BL scores were at entry into the RCT. Further analyses, using comparable BL scores (at RCT entry) for all treatment groups will better characterize this patient subgroup. The lack of significant associations based on response status could partly be explained by the definition of ‘responders’, which was based on clinician assessments and may not have fully captured the patient experience. For all other subgroup analyses, sample sizes were small and not powered to show significant associations.    Study funded by GSK/Human Genome Sciences, Inc. Nicole Cash, MRes PhD, Fishawack Indicia Ltd, UK, provided editorial assistance, funded by GSK.