Belimumab Shows Favorable Long-Term Disease Control in Patients With SLE

Disease control, as well as safety data, was achieved and maintained in patients with systemic lupus erythematosus (SLE) receiving belimumab for ≤6 years, according to a study published in RMD Open.¹

“The long-term safety and efficacy of belimumab were demonstrated in 2 open-label continuation studies (BEL112233 and BEL112234) and supported by a pooled interim analysis of these 2 studies. The safety and efficacy of belimumab were also demonstrated in the phase 3 double-blind, placebo-controlled 52-week study (BLISS-NEA) in patients with SLE from Northeast Asia,” investigators stated. “However, there are limited data on the long-term safety and efficacy of belimumab in Chinese patients with SLE.”

Chinese patients included in the Phase 3, open-label BEL113750 study received intravenous belimumab 10 mg/kg every 28 days for up to 6 years, in addition to standard therapy, with the primary endpoint focusing on safety. Other endpoints were the SLE Responder Index (SRI)-4 response rate (defined as a ≥4-point reduction from baseline in Safety of Estrogens in Lupus Erythematosus National Assessment version of the SLE Disease Activity Index [SELENA-SLEDAI]), severe flares, and any changes in prednisone from baseline through the end of the study. Registered patients were able to opt into the open-label period after completing the double-blind BLISS-NEA study between October 2013 and September 2018.

Of the 424 patients enrolled, half (n = 215) ultimately completed the study. Most (84.7%; n = 359/424) experienced adverse events (AEs), with 22.6% (n = 96/424) reporting serious AEs. A total of 6.1% (n = 24/424) discontinued the drug due to AEs. The most frequently reported AEs were upper respiratory tract infections (35.4%) and viral upper respiratory tract infections (13.9%). However, incidences of AEs were either stable or declined thought the study period.

Systemic reaction rate post-infusion was 1.5 events per 100 patient-years and the herpes zoster infection rate was 3.0 events per 100 patient-years. No suicide attempts or serious depression were reported.

Severe flares were experienced by 13.9% of patients (n = 55/396), with median time to first flare reported as 377 days.

The percentage of SRI-4 responders increased gradually throughout the long-term study. At year 1, week 24, 190/346 (54.9%) patients achieving SIR-4, compared with year 5, week 48 (66/82 [80.5%]).

For patients receiving a prednisone-equivalent dose >7.5 mg/day (n = 335), dosage reduction to ≤7.5 mg/day increased throughout the study (year 1: 30/333 [9.0%]; year 5: 36/67 [53.7%]).

The study was limited by the small sample size, which was further reduced by approximately half, as well as the lack of a placebo control group. Further, the patients who enrolled in the study had already completed the previous double-blind 52-week study and were therefore more likely to respond well to belimumab treatment. Lastly, results may have been impacted due to the baseline definition of the analysis differing for each of the randomized treatment groups in the BLISS-NEA study.

“Belimumab therapy for up to 6 years in patients with SLE in China was well tolerated with no new safety concerns identified, which is consistent with the previous long term belimumab studies,” investigators concluded. “These findings, along with a suggested continued efficacy benefit, support the positive benefit–risk profile of treatment with belimumab as an add-on to standard therapy in patients with active SLE in China.”

Reference:

Zhang F, Zheng J, Li Y, et al. Phase 3, long-term, open-label extension period of safety and efficacy of belimumab in patients with systemic lupus erythematosus in China, for up to 6 years. RMD Open. 2022;8(1):e001669. doi:10.1136/rmdopen-2021-001669