Disease characteristics predict belimumab response in SLE
medwireNews: High disease activity, short disease duration, and low baseline damage are associated with an increased response to belimumab in patients with systemic lupus erythematosus (SLE), real world study data show.
“At present, belimumab is frequently used as the last option in SLE treatment,” note Andrea Doria (University of Padova, Italy) and co-authors in Arthritis & Rheumatology.
“Based on our data, we suggest that an earlier use of belimumab in patients with active SLE may maximize its efficacy, since it improves patient prognosis in terms of better response, achievement of remission/LDA [low disease activity] and hindrance of damage accrual.”
Doria and team analyzed data for 466 patients (mean age 41 years, 92% women) with active SLE (mean duration 12 years) who received intravenous belimumab at 24 centers across Italy.
Of these, 49.2% achieved an SRI-4 response within 6 months. After adjustment for potential confounders, the researchers found that a baseline SLEDAI-2K of 10 or higher and a disease duration of 2 years or shorter were significantly associated with an increased likelihood of a response at 6 months, at odds ratios (ORs) of 3.14 and 1.94, respectively. Skin involvement at baseline predicted a lower likelihood of a response, at an OR of 0.42.
At 12 months, the proportion of responders had increased to 61.3% and the likelihood of a response was again significantly higher among individuals with a baseline SLEDAI-2K of 10 or higher (OR=3.48) and also among those with baseline musculoskeletal involvement (OR=1.98) and a baseline Systemic Lupus International Collaborating Clinics damage index (SDI) of 0 (OR=1.74).
The response rate was highest at 24 months, at 69.7%, and at this timepoint was still significantly higher among individuals with a baseline SLEDAI-2K of 10 or higher (OR=4.25) as well as those with a disease duration of up to 2 years (OR=3.79).
The SRI-4 response remained relatively stable between 24 and 36 months, at which point it was 69.6%. The only variable associated with an increased likelihood of a response at 36 months was a baseline SLEDAI-2K of 10 or higher (OR=14.59). By contrast, baseline smoking was associated with a significantly lower odds of a response at this time, with an OR of 0.19.
The investigators also report that remission rates (cSLEDAI=0 and prednisone ≤5 mg/day with immunosuppressants and antimalarials at a stable dose) increased from 24.9% at 6 months to 49.4% at 36 months, while LDA rates (cSLEDAI ≤2) increased from 55.6% to 78.9%.
Spending at least 25% of the median 18-month follow-up period in remission or at least 50% of the time with LDA was associated with significantly less damage, with both remission and LDA predicted by a baseline SLEDAI-2K below 10 and an SDI of 0, at ORs ranging from 1.9 to 3.2.
Doria et al note that the contradiction between people with higher baseline disease activity being more likely to achieve SRI-4 response at different timepoints, but less likely to achieve a cumulative remission of at least 25% or LDA of at least 50% of follow-up “may be explained considering that an initial drop of 4 SLEDAI-2K points may be more promptly achieved in patients with higher baseline disease activity, thereby leading to a faster SRI-4 achievement, while requiring a longer time for a high cSLEDAI to flatten to ≤2 or to zero i.e. to reach LDA or remission.”
They conclude: “The early use of belimumab in patients with active SLE and low baseline damage predicts favorable outcomes in a real‐life setting.”
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