medwireNews: Preliminary results from a phase Ib trial suggest that add-on treatment with the anti-immunoglobulin (Ig)E antibody omalizumab may be a feasible option for patients with systemic lupus erythematosus (SLE).
“The identification of IgE autoantibodies and their role in basophil activation in animal models and in human SLE has revealed a new pathway potentially involved in SLE pathogenesis,” explain Sarfaraz Hasni (National Institutes of Health, Bethesda, Maryland, USA) and co-investigators.
The researchers randomly assigned 15 SLE patients with elevated levels of autoreactive IgE antibodies (>2 standard deviations above the mean of healthy controls) to receive 16 weeks of treatment with subcutaneous omalizumab at a loading dose of 600 mg followed by 300 mg every 4 weeks or placebo. Patients in both arms were then given open-label omalizumab for 16 weeks, followed by a 4-week observation period after the study drug was discontinued. All participants continued to receive background immunosuppressive therapy and glucocorticoids throughout the trial.
Hasni and team report in Arthritis & Rheumatology that omalizumab was “well tolerated in patients with SLE,” and that no allergic reactions occurred over the study period.
A total of 15 patients experienced 52 adverse events (AEs) over the study period, the majority (94.2%) of which were mild or moderate in severity. During the placebo-controlled part of the trial, nine AEs were reported in the 10 patients treated with omalizumab, while the five participants given placebo experienced 12 AEs. The study authors say that “[n]o trend of involvement of a particular organ system was identified” in the safety analysis.
Patients in the omalizumab group experienced a significantly greater improvement in median SLEDAI-2K score from baseline to week 16 than those in the placebo arm. However, Hasni and colleagues point out that the magnitude of difference between the two groups was just 2 points, which “may not be clinically meaningful,” and note that there were no significant differences in other clinical measures between the groups.
“This exploratory study was not powered for efficacy and a larger sample size will be needed to ascertain if omalizumab has a potential to treat a selected subset of patients with SLE and high levels of anti-IgE antibodies,” write the researchers.
They also caution that their study was restricted to “a small number of patients with mild clinical disease with no organ threatening manifestations,” and that “[t]he safety data from this study [need] to be confirmed in a larger cohort with more active disease.”
Nonetheless, the investigators stress that “this is the first trial to test the safety and potential efficacy of blocking IgE autoantibodies as a novel non-immunosuppressive agent in treatment of SLE.”
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