Belimumab an ‘appropriate’ option for childhood-onset SLE
medwireNews: The addition of belimumab to standard therapy improves response rates and has manageable toxicity in patients with childhood-onset systemic lupus erythematosus (cSLE), suggest findings from the phase 2 PLUTO study.
The researchers note that although a trial with “a large sample size powered for statistical significance testing was deemed unfeasible” due to the “severity and relatively low cSLE prevalence,” the favorable findings of their study have “contributed to belimumab’s approval in several countries as an add-on therapy in children with cSLE.”
In the PLUTO trial, reported in the Annals of the Rheumatic Diseases, the primary endpoint of SRI4 at week 52 was achieved by 52.8% of the 53 patients aged 5–17 years who were randomly assigned to receive intravenous belimumab 10 mg/kg every 4 weeks alongside standard therapy.
This was higher than the rate of 43.6% observed among their 40 counterparts who instead received placebo plus standard therapy, and translated into a 49% increased likelihood of achieving an SRI4 response with belimumab versus placebo.
The rate of responses also favored belimumab when assessed by the PRINTO/ACR30 alternative criteria (52.8 vs 27.5%) and PRINTO/ACR50 criteria (60.4 vs 35.0%).
And there was a greater proportion of sustained SRI4 responses – lasting up to at least week 44 – with belimumab versus placebo (43.4 vs 41.0%) as well as sustained improvement in the Parent Global Assessment of patient wellbeing (59.1 vs 33.3%).
Furthermore, the incidence of severe flare was lower among belimumab-treated patients than those given placebo, at 17% and 35%, respectively, which equated to a significant 64% reduction in the risk for severe flare with belimumab.
The researchers say that “belimumab was well tolerated by paediatric patients,” with “no new safety concerns,” and an adverse event (AE) profile that was “consistent with observations in adults with SLE.”
The incidence of AEs was comparable in the belimumab and placebo groups (79.2 vs 82.5%) while the proportion of patients experiencing at least one severe AE was lower in the belimumab arm (17.0 vs 35.0%). There were no reports of suicidal ideation or behavior in the belimumab group, compared with three in the placebo group.
And three patients given belimumab discontinued treatment due to AEs, as did five placebo-treated patients.
Hermine Brunner, from the University of Cincinnati in Ohio, USA, and team conclude that “within the limits of data analysed to date (1 year), the benefit-risk profile of belimumab 10 mg/kg intravenous in children with cSLE appears favourable and consistent with adults, confirming 10 mg/kg intravenous is appropriate for paediatric populations.”
They add: “[T]he ongoing follow-up phase will provide further evidence regarding long-term (up to 10 years) safety and efficacy of belimumab in children with cSLE.”
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