LB001EFFICACY AND SAFETY OF BELIMUMAB IN PATIENTS WITH ACTIVE LUPUS NEPHRITIS: A PHASE 3, RANDOMISED, PLACEBO-CONTROLLED TRIAL
Authors: Rovin Brad , Houssiau Frédéric A , Furie Richard , Malvar Ana , Teng Y K O , Mok Chi Chiu , Contreras Gabriel , Yu Xueqing , Dolff Sebastian , Ji Beulah , Roth David , Kleoudis Christi , Bass Damon , Madan Anuradha , Wright Amanda , Barnett Carly , Green Yulia 
Published: June 2020

Abstract

Background and Aims
Belimumab (BEL), an anti-B-cell-activating factor (BAFF) monoclonal antibody, is approved in patients (pts) ≥5 years of age with active systemic lupus erythematosus (SLE). Post hoc analyses of pooled renal outcomes data from two Phase 3 SLE studies showed favourable trends of greater reduction in proteinuria, haematuria, pyuria and lower renal flare rates in BEL-treated pts vs placebo (PBO).1 This is the largest study in acute lupus nephritis (LN) to date that evaluated efficacy and safety of intravenous (IV) BEL plus standard therapy (ST) in pts with active LN.

Method
BLISS-LN is a Phase 3, randomised, double-blind, placebo-controlled, 104-week study (GSK study BEL114054, NCT01639339); eligible pts (≥18 years) with autoantibody-positive SLE and active, biopsy-proven LN (classes III, IV and/or V) were randomised (1:1) to monthly BEL 10 mg/kg IV or PBO, plus ST. Randomisation was stratified by induction regimen: high dose corticosteroids [HDCS] plus either cyclophosphamide (CyC), followed by azathioprine + low dose corticosteroids (LDCS), or mycophenolate mofetil (MMF), followed by MMF + LDCS. Primary endpoint: primary efficacy renal response (PERR; defined as urine protein creatinine ratio [uPCR] ≤0.7; estimated glomerular filtration rate [eGFR] no more than 20% below pre-flare value or ≥60 ml/min/1.73m2; no rescue therapy) at Week (Wk) 104. Key secondary endpoints: complete renal response (CRR; defined as uPCR &lt;0.5; eGFR no more than 10% below pre-flare value or ≥90 ml/min/1.73m2; no rescue therapy) at Wk 104; PERR at Wk 52; risk of renal-related event (defined as end-stage renal disease/doubling of serum creatinine/renal worsening/renal disease-related treatment failure) or death at any time up to Wk 104. Other endpoints: PERR and CRR at Wk 104 by induction regimen; proportions of pts with baseline uPCR ≥0.5 with uPCR shift to &lt;0.5 while on study.

Results
Overall, 448 pts were randomised (efficacy: 223/treatment group; safety: 224/treatment group); 118 pts received CyC induction and 328 MMF induction; 278 (62.3%) completed the treatment.
At Wk 104, 43.0% BEL and 32.3% PBO pts achieved PERR (OR [95% CI] vs PBO 1.55 [1.04, 2.32], p=0.0311); 30.0% BEL and 19.7% PBO pts achieved CRR (OR [95% CI] vs PBO 1.74 [1.11, 2.74], p=0.0167). Over 104 weeks, more BEL than PBO pts achieved CRR at each visit (Figure 1A). PERR at Wk 52 was achieved by 46.6% BEL and 35.4% PBO pts (OR [95% CI] vs PBO 1.59 [1.06, 2.38], p=0.0245).
The risk of a renal-related event or death was 49% lower with BEL than PBO (HR [95%CI] 0.51 [0.34, 0.77]; p=0.0014) at any time point during the study. Overall, 15.7% of BEL and 28.3% of PBO pts experienced a renal-related event or death.
When analysed by induction regimen, PERR at Wk 104 was achieved by 33.9% BEL and 27.1% PBO CyC-induced pts (OR [95% CI] vs PBO 1.52 [0.66, 3.49], p=0.3272), and by 46.3% BEL and 34.1% PBO MMF-induced pts (OR [95% CI] vs PBO 1.58 [1.00, 2.51], p=0.0501). CRR at Wk 104 was achieved by 18.6% BEL and 18.6% PBO CyC-induced pts (OR [95% CI] vs PBO 1.07 [0.41, 2.78], p=0.8843), and by 34.1% BEL and 20.1% PBO MMF-induced pts (OR [95% CI] vs PBO 2.01 [1.19, 3.38], p=0.0085).
Proportions of pts with uPCR shift from ≥0.5 at baseline to &lt;0.5 while on study (calculated post hoc) are presented in the Figure 1B.
Overall, 95.5% BEL and 94.2% PBO pts had ≥1 adverse event (AE); 25.9% BEL and 29.9% PBO pts had ≥1 serious AE; 13.8% BEL and 17.0% PBO pts had serious infections; 12.9% pts in each group had ≥1 AE resulting in study treatment discontinuation; on-treatment fatal AEs were reported in 1.8% BEL and 1.3% PBO pts.

Conclusion
BEL demonstrated improved renal responses vs PBO in pts with active LN, with a safety profile consistent with previous BEL trials.