Belimumab Safe and Effective Treating Systemic Lupus Erythematosus

Yoshiya Tanaka, MD, PhD

In data planned for presentation during the European Congress of Rheumatology (EULAR) 2020 meeting, investigators may have found an effective drug to treat systemic lupus erythematosus (SLE).

A team, led by Yoshiya Tanaka, MD, PhD, University of Occupational and Environmental Health, evaluated the long-term safety and efficacy of intravenous belimumab combined with standard systemic lupus erythematosus therapy for patients with SLE in Japan and Korea.

Systemic Lupus erythematosus is more prevalent in Asian populations compared the rest of the world. However, belimumab, a monoclonal antibody targeting B-lymphocyte stimulator, has shown promise and is currently approved for patients older than 5 with active, autoantibody-positive SLE.

In the phase 3, multicenter, open label trial, the investigators examined 142 adult patients who completed a double-blind phase of the GSK study of belimumab in Japan or South Korea or the subcutaneous open-label phase of the GSK study of belimumab in Japan.

The study included 72 patients in Japan and 70 individuals in Korea, with 104 (73.2%) patients completing the study, 37 patients (26.1%) withdrawing, and 1 (0.7%) participant dying.

Each participant received 10mg/kg of the intravenous study drug monthly along with standard systemic lupus erythematosus therapy.

The investigators sought primary endpoints of safety assessments and key secondary endpoints of SR14 response rate at each scheduled visit based on observed data, defined as a ≥4-point reduction from baseline in SELENA-SLEDAI score, no worsening in PGA (<0.3-point increase from baseline) and no new BILAG 1A/2B organ domain scores; time to first severe SFI flare over time.

The team analyzed endpoints relative to the first belimumab dose in either the parent or current study. However, the researchers did not collect follow-up data following study withdrawal.

A total of 139 (97.9%) of patents had at least 1 adverse event, with the most frequent adverse events including nasopharyngitis (60.6%); headache (28.2%); cough, herpes zoster and viral upper respiratory tract infection (18.3% each).

In addition, serious adverse events occurred in 48 patients (33.8%), including infections and infestations, reported in 24 (16.9%) patients.

During the study, the annual incidence of adverse events, including both serious adverse events and adverse events of special interest, remained stable or declined, with no trends of clinical concerns regarding the incidence of Grade 3 or 4 values for laboratory parameters. There was also 1 transient positive immunogenicity result of no clinical concern.

The investigators found the proportion of SR14 responders was 47.8% at year 1 (week 24). This proportion increased dramatically to 84.6% at year 7 (week 48). The proportion of patients with at least a 4-point decrease from baseline in SELENA-SLEDAI score increased from 51.5% at year 1 (week 24) to 84.6% at year 7 (week 48) and the proportion of patients with no PGA worsening was between 91.3-100%.

The proportion of patients with no new BILAG 1A/2B organ domain scores was 93.3-100% up to Year 7 (Week 48), with a total of 21 (14.8%) patients suffering from 24 severe SFI flares.

“BEL was well tolerated as add-on therapy to SST for ≤7 years in pts with SLE from Japan/Korea,” the authors wrote. “Safety results were consistent with the known BEL safety profile.”

The study, “A Phase 3, Open-Label, Continuation Study Evaluating Long-Term Safety and Efficacy of Belimumab in Patients From Japan and Korea with Systemic Lupus Erythematosus for Up to 7 Years,” was published online by EULAR.