Benralizumab does not elicit therapeutic effect in patients with chronic spontaneous urticaria: results from the phase IIb multinational randomized double-blind placebo-controlled ARROYO trial.

ABSTRACT

BACKGROUND: Chronic spontaneous urticaria (CSU) is a relatively common skin disease associated with hives and angio-oedema. Eosinophils play a role in CSU pathogenesis. Benralizumab, an anti-interleukin-5 receptor-α monoclonal antibody, has been shown to induce nearly complete depletion of eosinophils. OBJECTIVES: To determine the clinical efficacy and safety of benralizumab in patients with CSU who were symptomatic despite H1 antihistamine treatment. METHODS: The 24-week, randomized, double-blind, placebo-controlled, phase IIb portion of the ARROYO trial enrolled adult patients with CSU who were currently on H1 antihistamine treatment. Patients were randomized to one of five treatment groups according to benralizumab dose and regimen for a 24-week treatment period. The primary endpoint was change from baseline in Itch Severity Score (ISS)7 at week 12. The key secondary endpoint was change from baseline in Urticaria Activity Score (UAS)7 at week 12. Additional secondary endpoints included other metrics to assess CSU at week 24, blood eosinophil levels, and pharmacokinetics and immunogenicity assessments. Exploratory subgroup analyses were conducted to explore responses according to demographics, clinical features and biomarkers. Safety was assessed in all treatment groups. RESULTS: Of 155 patients, 59 were randomized to benralizumab 30 mg, 56 to benralizumab 60 mg and 40 to placebo. Baseline and disease characteristics were consistent with what was expected for patients with CSU. There were no significant differences in change from baseline in ISS7 score at week 12 between benralizumab and placebo [benralizumab 30 mg vs. placebo, least-squares mean difference -1.01, 95% confidence interval (CI) -3.28 to 1.26; benralizumab 60 mg vs. placebo, least-squares mean difference -1.79, 95% CI -4.09 to 0.50] nor in change from baseline in UAS7 score at week 12 between benralizumab and placebo (benralizumab 30 mg vs. placebo, P = 0.407; benralizumab 60 mg vs. placebo, P = 0.082). Depletion of blood eosinophil levels was observed at week 24 in patients treated with benralizumab. All other secondary endpoints and exploratory/subgroup analyses indicated no significant differences between benralizumab and placebo. Safety results were consistent with the known profile of benralizumab. CONCLUSIONS: Although benralizumab resulted in near-complete depletion of blood eosinophils, there was no clinical benefit over placebo.

Chronic spontaneous urticaria (CSU) is a common disease characterized by hives, itching and inflammation (swelling) of the skin. CSU is mainly driven by what we call 'mast cells'. 'Eosinophils' are a type of white blood cell that protect the body from infections and allergens. These cells are abundant in skin biopsy samples of people with CSU, especially in the hives that contribute to swelling. Therefore, we thought that reducing eosinophils would be beneficial for treating CSU. Benralizumab is a drug that has been shown to reduce eosinophils in other diseases. This study, called 'ARROYO', was a 24-week clinical trial that compared benralizumab treatment with a placebo (inactive medicine) in adults with CSU who were taking antihistamines. We aimed to determine whether benralizumab would improve symptoms of CSU over time. Several assessments were used to measure changes in CSU symptoms, including hives, severity of itchiness, swelling of the skin, and other aspects related to overall psychological and physical wellbeing. The characteristics of the 155 people who took part in this study were consistent with what was expected for patients with CSU. We found that while benralizumab reduced eosinophil levels in people with CSU, there were no differences in symptoms in people receiving benralizumab compared with those receiving placebo. There were no new safety concerns related to benralizumab and no deaths. Overall, although benralizumab is effective at reducing the number of eosinophils, it is not effective at treating the symptoms of CSU. More studies are needed to uncover potential treatment targets in CSU.