Background/Purpose:

Epratuzumab is a monoclonal antibody targeting CD22. In EMBLEM^TM (a dose-ranging phase IIb study), epratuzumab produced clinically relevant improvements in disease activity in patients with moderate-to-severe systemic lupus erythematosus (SLE).¹ The open-label extension (OLE) of EMBLEM^TM (NCT00660881) reports long-term data on the efficacy of epratuzumab. The improvement in British Isles Lupus Assessment Group (BILAG) 2004 index according to body systems is reported.

Methods:

Patients from any EMBLEM^TM arm completing 12 weeks’ blinded treatment and patients who discontinued due to lack of efficacy but completed ≥8 weeks were eligible. In the OLE, all patients received 1200mg epratuzumab at weeks 0 and 2 of repeating 12-week cycles. Data are reported to week 108, the last time point when more than 50% of patients reported data for BILAG improvement. Independent central readers determined BILAG grades for all 9 systems. Data for the BILAG improvement component of the combined index in body systems for which a sufficient number of patients entering the OLE (≥20) had baseline disease activity to assess response are reported. Observed case analysis are presented.

Results:

Improvements from BILAG A/B scores to BILAG C or D were observed following 12 weeks of epratuzumab treatment (EMBLEM^TM OLE screening) in all body systems (Table). In the musculoskeletal body system 44.8% of patients with BILAG A/B at EMBLEM^TM baseline improved to BILAG C or D at EMBLEM^TM OLE screening. This was 41.6%, 34.7%, 36.0%, 84.1% and 52.0% in the mucocutaneous, cardiorespiratory, neuropsychiatric, constitutional and renal body systems respectively. The percentage of patients with an improvement in baseline BILAG A/B scores to BILAG C or D was further increased up to week 108 in the EMBLEM^TM OLE. At week 108 the proportion of patients with BILAG C or D exceeded 60% in the musculoskeletal, mucocutaneous, cardiorespiratory, constitutional and renal systems (observed data) (Table).

Conclusion:

Treatment with epratuzumab provided BILAG improvements in disease activity in all affected body systems. Improvements were sustained and enhanced with long-term treatment. Within specific body systems, most patients had symptom reduction or absence of active disease with treatment.

References:

1.   Wallace DJ. et al. Ann Rheum Dis, Online First 12 January 2013. DOI: 10.1136/annrheumdis-2012-202760.