Long-term Safety and Efficacy of Benralizumab for Eosinophilic Granulomatosis with Polyangiitis Complicated with Severe Neuropathy

Churg-Strauss syndrome (CSS) is classified among the so-called antineutrophil cytoplasmic antibody-associated systemic vasculitides (AASVs) because of its clinicopathologic features that overlap with the other AASVs. However, while antineutrophil cytoplasmic antibodies (ANCAs) are consistently found in 75-95% of patients with Wegener's granulomatosis or microscopic polyangiitis, their prevalence in CSS varies widely and their clinical significance remains uncertain. We undertook this study to examine the prevalence and antigen specificity of ANCAs in a large cohort of patients with CSS. Moreover, we evaluated the relationship between ANCA positivity and clinicopathologic features. Immunofluorescence and enzyme-linked immunosorbent assay were used to determine the presence or absence of ANCAs in 93 consecutive patients at the time of diagnosis. The main clinical and pathologic data, obtained by retrospective analysis, were correlated with ANCA status. ANCAs were present by immunofluorescence in 35 of 93 patients (37.6%). A perinuclear ANCA (pANCA) pattern was found in 26 of 35 patients (74.3%), with specificity for myeloperoxidase (MPO) in 24 patients, while a cytoplasmic ANCA pattern, with specificity for proteinase 3, was found in 3 of 35 patients (8.6%). Atypical patterns were found in 6 of 30 patients with anti-MPO antibodies (20.0%). ANCA positivity was associated with higher prevalences of renal disease (51.4% versus 12.1%; P < 0.001) and pulmonary hemorrhage (20.0% versus 0.0%; P = 0.001) and, to a lesser extent, with other organ system manifestations (purpura and mononeuritis multiplex), but with lower frequencies of lung disease (34.3% versus 60.3%; P = 0.019) and heart disease (5.7% versus 22.4%; P = 0.042). ANCAs are present in approximately 40% of patients with CSS. A pANCA pattern with specificity for MPO is found in most ANCA-positive patients. ANCA positivity is mainly associated with glomerular and alveolar capillaritis.

Many asthmatic patients exhibit sputum eosinophilia associated with exacerbations. Benralizumab targets eosinophils by binding IL-5 receptor α, inducing apoptosis through antibody-dependent cell-mediated cytotoxicity. We sought to evaluate the safety of benralizumab in adults with eosinophilic asthma and its effects on eosinophil counts in airway mucosal/submucosal biopsy specimens, sputum, bone marrow, and peripheral blood. In this multicenter, double-blind, placebo-controlled phase I study, 13 subjects were randomized to single-dose intravenous placebo or 1 mg/kg benralizumab (day 0; cohort 1), and 14 subjects were randomized to 3 monthly subcutaneous doses of placebo or 100 or 200 mg of benralizumab (days 0, 28, and 56; cohort 2). Cohorts 1 and 2 were consecutive. The incidence of adverse events was similar between groups. No serious adverse events related to benralizumab occurred. In cohort 1 intravenous benralizumab produced a median decrease from baseline of 61.9% in airway mucosal eosinophil counts (day 28; placebo: +19.6%; P = .28), as well as an 18.7% decrease (day 21) in sputum and a 100% decrease (day 28) in blood counts. Eosinophils were not detectable in bone marrow of benralizumab-treated subjects (day 28, n = 4). In cohort 2 subcutaneous benralizumab demonstrated a combined (100 + 200 mg) median reduction of 95.8% in airway eosinophil counts (day 84; placebo, 46.7%; P = .06), as well as an 89.9% decrease (day 28) in sputum and a 100% decrease (day 84) in blood counts. Single-dose intravenous and multiple-dose subcutaneous benralizumab reduced eosinophil counts in airway mucosa/submucosa and sputum and suppressed eosinophil counts in bone marrow and peripheral blood. The safety profile supports further development. Additional studies are needed to assess the clinical benefit in asthmatic patients. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.