Mepolizumab incompletely suppresses clinical flares in a pilot study of episodic angioedema with eosinophilia.

BACKGROUND: Episodic angioedema with eosinophilia (EAE) is a rare multilineage cyclic syndrome of unknown etiology characterized by episodes of angioedema, myalgia, fatigue, and fever that occur every 3 to 8 weeks and resolve between episodes without therapy. Cyclic elevations in serum IL-5 levels and neutrophils precede the increase in absolute eosinophil count (AEC) in most patients. OBJECTIVE: We sought to assess the role of IL-5-driven eosinophilia in the clinical manifestations of EAE. METHODS: An open-label pilot study of mepolizumab (700 mg intravenously monthly for 3 months followed by sequential dose reduction to the Food and Drug Administration-approved dose of 300 mg subcutaneously monthly) was conducted. The primary end point was reduction in the number and severity of clinical symptoms as assessed by patient-reported symptom questionnaires. Secondary end points were greater than or equal to 75% reduction in peak AEC after 1 dose of mepolizumab and sustained reduction in AEC after 3 doses of mepolizumab. Exploratory end points included effects of mepolizumab treatment on other cell lineages (numbers and surface marker expression), levels of plasma mediators, and biomarkers of eosinophil activation. RESULTS: Four female and 1 male (median age, 45 years) participants with EAE were enrolled. None of the 5 participants experienced a reduction in the number of symptomatic flares on mepolizumab therapy, and 1 participant withdrew before study completion because of lack of improvement. Peak AEC was reduced by 75% or more in 3 participants after the first dose of mepolizumab and in 4 participants after 3 doses. CONCLUSIONS: In a small cohort of participants with EAE, mepolizumab was unsuccessful in substantially reducing clinical symptoms despite reduction in AEC.

Immune Response Dynamics and Biomarkers in COVID-19 Patients.

BACKGROUND: The immune response dynamics in COVID-19 patients remain a subject of intense investigation due to their implications for disease severity and treatment outcomes. We examined changes in leukocyte levels, eosinophil activity, and cytokine profiles in patients hospitalized with COVID-19. METHODS: Serum samples were collected within the first 10 days of hospitalization/confirmed infection and analyzed for eosinophil granule proteins (EGP) and cytokines. Information from medical records including comorbidities, clinical symptoms, medications, and complete blood counts were collected at the time of admission, during hospitalization and at follow up approximately 3 months later. RESULTS: Serum levels of eotaxin, type 1 and type 2 cytokines, and alarmin cytokines were elevated in COVID-19 patients, highlighting the heightened immune response (p < 0.05). However, COVID-19 patients exhibited lower levels of eosinophils and eosinophil degranulation products compared to hospitalized controls (p < 0.05). Leukocyte counts increased consistently from admission to follow-up, indicative of recovery. CONCLUSION: Attenuated eosinophil activity alongside elevated chemokine and cytokine levels during active infection, highlights the complex interplay of immune mediators in the pathogenesis COVID-19 and underscores the need for further investigation into immune biomarkers and treatment strategies.

Anti-Siglec-8 Antibody for Eosinophilic Gastritis and Duodenitis.

BACKGROUND: Eosinophilic gastritis and duodenitis are characterized by gastrointestinal mucosal eosinophilia, chronic symptoms, impaired quality of life, and a lack of adequate treatments. Mast-cell activity may contribute to the pathogenesis of the conditions. AK002 (lirentelimab) is an anti-Siglec-8 antibody that depletes eosinophils and inhibits mast cells and that has shown potential in animal models as a treatment for eosinophilic gastritis and duodenitis. METHODS: In this phase 2 trial, we randomly assigned adults who had symptomatic eosinophilic gastritis, eosinophilic duodenitis, or both conditions in a 1:1:1 ratio to receive four monthly infusions of low-dose AK002, high-dose AK002, or placebo. The primary end point was the change in gastrointestinal eosinophil count from baseline to 2 weeks after the final dose; to maximize statistical power, we evaluated this end point in the placebo group as compared with the combined AK002 group. Secondary end points were treatment response (>30% reduction in total symptom score and >75% reduction in gastrointestinal eosinophil count) and the change in total symptom score. RESULTS: Of the 65 patients who underwent randomization, 43 were assigned to receive AK002 and 22 were assigned to receive placebo. The mean percentage change in gastrointestinal eosinophil count was -86% in the combined AK002 group, as compared with 9% in the placebo group (least-squares mean difference, -98 percentage points; 95% confidence interval [CI], -121 to -76; P<0.001). Treatment response occurred in 63% of the patients who received AK002 and in 5% of the patients who received placebo (difference, 58 percentage points; 95% CI, 36 to 74; P<0.001). The mean change in total symptom score was -48% with AK002 and -22% with placebo (least-squares mean difference, -26 percentage points; 95% CI, -44 to -9; P = 0.004). Adverse events associated with AK002 were similar to those with placebo, with the exception of higher percentages of patients having mild-to-moderate infusion-related reactions with AK002 (60% in the combined AK002 group and 23% in the placebo group). CONCLUSIONS: In patients with eosinophilic gastritis or duodenitis, AK002 reduced gastrointestinal eosinophils and symptoms. Infusion-related reactions were more common with AK002 than with placebo. (Funded by Allakos; ENIGMA ClinicalTrials.gov number, NCT03496571.).

Distinct CRTH2+CD161+ (peTh2) memory CD4+ T-cell cytokine profiles in food allergy and eosinophilic gastrointestinal disorders.

INTRODUCTION: Although IgE-mediated food allergy (FA) and eosinophilic gastrointestinal disorders (EGID) are clinically distinct and treated differently, pathogenic effector Th2 (peTh2) cells are implicated in the pathogenesis of both FA and EGID. The aim of this study was to better characterize peTh2 cells in the context of FA and EGID and the overlap between these two conditions. METHODS: Peripheral blood peTh2 cells (CD3+CD4+CD27-CD49d+CRTH2+CD161+) were profiled by intracellular cytokine flow cytometry in the following patient cohorts: patients with FA alone (n = 8), FA and food-triggered EGID (EGID+FA+FT, n = 7), food-triggered EGID alone (EGID+FT, n = 7), EGID without FA or specific food triggers (ONLY_EGID, n = 9), and healthy volunteers (HV, n = 7). Overnight peripheral blood mononuclear cell (PBMC) culture supernatants were assessed for cytokine production by multiplex analysis. RESULTS: CRTH2+CD161+ (peTh2) memory CD4+ T cells were significantly increased in both patients with FA and those with ALL_EGID (inclusive of EGID+FA+FT, EGID+FT and ONLY_EGID) when compared to HV. However, ALL_EGID patients, particularly those with EGID+FA+FT, had significantly elevated IL-5+IL-13+ peTh2 cells, whereas FA patients had significantly elevated IFN-γ or IL-17A-expressing peTh2 cells. This finding was supported by increased spontaneous IL-5 and IL-13 production in overnight cultures of PBMC from EGID+FA+FT patients compared to spontaneous IL-10 and IFN-γ production by PBMC from FA patients. FA patients had increased IL-9, IL-10, IL-17A, and IFN-γ production in overnight cultures of stimulated PBMC. CONCLUSIONS: EGID and IgE-mediated FA share a common cell subtype defined by specific surface markers and termed CRTH2+CD161+ (peTh2) memory CD4+ T cells. However, the cytokine profiles of these CRTH2+CD161+ (peTh2) memory CD4+ T cells are markedly different between the two disorders.

Proposed refined diagnostic criteria and classification of eosinophil disorders and related syndromes.

Eosinophilia and eosinophil activation are recurrent features in various reactive states and certain hematologic malignancies. In patients with hypereosinophilia (HE), HE-induced organ damage is often encountered and may lead to the diagnosis of a hypereosinophilic syndrome (HES). A number of known mechanisms and etiologies contribute to the development of HE and HES. Based on these etiologies and the origin of eosinophils, HE and HES are divided into primary forms where eosinophils are clonal cells, reactive forms where an underlying reactive or neoplastic condition is detected and eosinophils are considered to be "non-clonal" cells, and idiopathic HE and HES in which neither a clonal nor a reactive underlying pathology is detected. Since 2012, this classification and the related criteria have been widely accepted and regarded as standard. However, during the past few years, new developments in the field and an increasing number of markers and targets have created a need to update these criteria and the classification of HE and HES. To address this challenge, a Working Conference on eosinophil disorders was organized in 2021. In this conference, a panel of experts representing the relevant fields, including allergy, dermatology, hematology, immunology, laboratory medicine, and pathology, met and discussed new markers and concepts as well as refinements in definitions, criteria and classifications of HE and HES. The outcomes of this conference are presented in this article and should assist in the diagnosis and management of patients with HE and HES in daily practice and in the preparation and conduct of clinical trials.

Urine eosinophil-derived neurotoxin: A potential marker of activity in select eosinophilic disorders.

BACKGROUND: Biomarkers of eosinophilic disease activity, especially in the context of novel therapies that reduce blood eosinophil counts, are an unmet need. Absolute eosinophil count (AEC) does not accurately reflect tissue eosinophilia or eosinophil activation. Therefore, the aims of this study were to compare the reliability of plasma and urine eosinophil major basic protein 1, eosinophil cationic protein, eosinophil-derived neurotoxin (EDN), and eosinophil peroxidase measurement and to evaluate the usefulness of eosinophil granule protein (EGP) measurement for the assessment of disease activity in patients with eosinophil-associated diseases treated with mepolizumab, benralizumab, or dexpramipexole. METHODS: Eosinophil granule protein concentrations were measured in serum, plasma, and urine from healthy volunteers and patients with hypereosinophilic syndrome (HES), eosinophilic granulomatosis with polyangiitis (EGPA), and eosinophilic asthma using a multiplex assay. RESULTS: Urine EGP concentrations remained stable, whereas serum and plasma EGP concentrations increased significantly with delayed processing. Plasma (p) EDN, but not urine (u) EDN, concentration correlated with AEC and negatively correlated with prednisone dose. Both pEDN and uEDN decreased significantly following treatment of HES patients with benralizumab and EGPA patients with mepolizumab. uEDN appeared to increase with clinical relapse in both patient groups. CONCLUSIONS: Measurement of EGP in urine is noninvasive and unaffected by cellular lysis. Although plasma and urine EDN concentrations showed a similar pattern following benralizumab and mepolizumab treatment, the lack of correlation between AEC or prednisone dose and uEDN concentrations suggests that measurement of uEDN may provide a potential biomarker of disease activity in patients with HES and EGPA.

False-Negative Testing for FIP1L1::PDGFRA by Fluorescence in situ Hybridization Is a Frequent Cause of Diagnostic Delay.

The imatinib-sensitive fusion gene FIP1L1::PDGFRA is the most frequent molecular abnormality identified in patients with eosinophilic myeloid neoplasms. Rapid recognition of this mutation is essential given the poor prognosis of PDGFRA-associated myeloid neoplasms prior to the availability of imatinib therapy. We report a case of a patient in whom delayed diagnosis resulted in cardiac transplantation for eosinophilic endomyocardial fibrosis. The delay in diagnosis was due, in part, to a false-negative result in fluorescence in situ hybridization (FISH) testing for FIP1L1::PDGFRA. To explore this further, we examined our cohort of patients presenting with confirmed or suspected eosinophilic myeloid neoplasms and found 8 additional patients with negative FISH results despite a positive reverse-transcriptase polymerase chain reaction test for FIP1L1::PDGFRA. More importantly, false-negative FISH results delayed the median time to imatinib treatment by 257 days. These data emphasize the importance of empiric imatinib therapy in patients with clinical features suggestive of PDGFRA-associated disease.

Benralizumab for PDGFRA-Negative Hypereosinophilic Syndrome.

BACKGROUND: Hypereosinophilic syndrome is a group of diseases defined by marked eosinophilia in blood or tissue and eosinophil-related clinical manifestations. Benralizumab is a monoclonal antibody against interleukin-5 receptor α, which is expressed on human eosinophils. METHODS: In this randomized, double-blind, placebo-controlled, phase 2 trial, we administered a series of three monthly subcutaneous injections of either benralizumab (at a dose of 30 mg) or placebo in 20 symptomatic patients who had PDGFRA-negative hypereosinophilic syndrome and an absolute eosinophil count of at least 1000 cells per cubic millimeter; all the patients were receiving stable therapy (drugs or dietary changes) for this disease. This regimen was followed by an open-label phase, during which the patient's background therapy could be tapered as tolerated, and an extension phase. The primary end point of the randomized phase was a reduction of at least 50% in the absolute eosinophil count at week 12. RESULTS: During the randomized phase, the primary end point occurred in more patients in the benralizumab group than in the placebo group (9 of 10 patients [90%] vs. 3 of 10 patients [30%], P = 0.02). During the open-label phase, clinical and hematologic responses were observed in 17 of 19 patients (89%) and were sustained for 48 weeks in 14 of 19 patients (74%); in the latter group, in 9 of 14 patients (64%), background therapies could be tapered. Bone marrow and tissue eosinophilia were also suppressed with benralizumab therapy. The most common drug-related adverse events, headache and an elevated lactate dehydrogenase level, occurred in 32% of the patients after the first dose of benralizumab and resolved within 48 hours in all patients. Other adverse events occurred with similar frequency in the two groups. Of the many potential predictors of response that were examined, only clinical disease subtype appeared to be associated with the initial response or relapse. CONCLUSIONS: In this small phase 2 trial, patients with PDGFRA-negative hypereosinophilic syndrome who received benralizumab for 12 weeks had lower absolute eosinophil counts than those who received placebo. During the open-label phase, clinical and hematologic responses were sustained for 48 weeks in 74% of the patients. Adverse events did not limit treatment. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov numbers, NCT00001406 and NCT02130882.).

Glucocorticoid-induced eosinopenia results from CXCR4-dependent bone marrow migration.

Glucocorticoids are considered first-line therapy in a variety of eosinophilic disorders. They lead to a transient, profound decrease in circulating human eosinophils within hours of administration. The phenomenon of glucocorticoid-induced eosinopenia has been the basis for the use of glucocorticoids in eosinophilic disorders, and it has intrigued clinicians for 7 decades, yet its mechanism remains unexplained. To investigate, we first studied the response of circulating eosinophils to in vivo glucocorticoid administration in 3 species and found that the response in rhesus macaques, but not in mice, closely resembled that in humans. We then developed an isolation technique to purify rhesus macaque eosinophils from peripheral blood and performed live tracking of zirconium-89-oxine-labeled eosinophils by serial positron emission tomography/computed tomography imaging, before and after administration of glucocorticoids. Glucocorticoids induced rapid bone marrow homing of eosinophils. The kinetics of glucocorticoid-induced eosinopenia and bone marrow migration were consistent with those of the induction of the glucocorticoid-responsive chemokine receptor CXCR4, and selective blockade of CXCR4 reduced or eliminated the early glucocorticoid-induced reduction in blood eosinophils. Our results indicate that glucocorticoid-induced eosinopenia results from CXCR4-dependent migration of eosinophils to the bone marrow. These findings provide insight into the mechanism of action of glucocorticoids in eosinophilic disorders, with implications for the study of glucocorticoid resistance and the development of more targeted therapies. The human study was registered at ClinicalTrials.gov as #NCT02798523.

The long non-coding RNA Morrbid regulates Bim and short-lived myeloid cell lifespan.

Neutrophils, eosinophils and 'classical' monocytes collectively account for about 70% of human blood leukocytes and are among the shortest-lived cells in the body. Precise regulation of the lifespan of these myeloid cells is critical to maintain protective immune responses and minimize the deleterious consequences of prolonged inflammation. However, how the lifespan of these cells is strictly controlled remains largely unknown. Here we identify a long non-coding RNA that we termed Morrbid, which tightly controls the survival of neutrophils, eosinophils and classical monocytes in response to pro-survival cytokines in mice. To control the lifespan of these cells, Morrbid regulates the transcription of the neighbouring pro-apoptotic gene, Bcl2l11 (also known as Bim), by promoting the enrichment of the PRC2 complex at the Bcl2l11 promoter to maintain this gene in a poised state. Notably, Morrbid regulates this process in cis, enabling allele-specific control of Bcl2l11 transcription. Thus, in these highly inflammatory cells, changes in Morrbid levels provide a locus-specific regulatory mechanism that allows rapid control of apoptosis in response to extracellular pro-survival signals. As MORRBID is present in humans and dysregulated in individuals with hypereosinophilic syndrome, this long non-coding RNA may represent a potential therapeutic target for inflammatory disorders characterized by aberrant short-lived myeloid cell lifespan.

No evidence of lymphatic filariasis transmission in Bamako urban setting after three mass drug administration rounds.

Lymphatic filariasis (LF) elimination activities started in Mali in 2005 in the most endemic areas and reached countrywide coverage in 2009. In 2004, the district of Bamako was endemic for LF with a prevalence of 1.5%. The current study was designed to determine LF endemicity level in the urban area of Bamako after three rounds of ivermectin and albendazole mass drug administration (MDA). A cross-sectional study was conducted in 2011 in Bamako city, consisting of human prevalence and entomological surveys. Volunteers aged 14 years and above were invited to participate and tested for evidence of Wuchereria bancrofti using night time blood thick smear microfilarial count and blood spots for LF antibodies using the SD BIOLINE Oncho/LF IgG4 Biplex rapid test (Ov16/Wb123). Mosquitoes were collected using CDC light and gravid traps and tested using molecular methods. Poolscreen software v2.0 was used to estimate vector transmission potential. Of the 899 volunteers, one (0.11%) was found to be positive for LF using the Oncho/LF IgG4 Biplex rapid test, and none was found to have Wuchereria bancrofti microfilariae. No mosquitoes were found infected among 6174 Culex spp. (85.2%), 16 Anopheles gambiae s.l. (An. gambiae s.l.) (0.2%), 26 Aedes spp. (0.4%), 858 Ceratopogonidae (11.8%) and 170 other insects not identified (2.3%) tested. Our data indicate that there was no active LF transmission in the low prevalence urban district of Bamako after three MDA rounds. These data helped the National LF programme move forward towards the elimination goal.

Infection-associated Immune Perturbations Resolve 1 Year Following Treatment for Loa loa.

BACKGROUND: We have previously demonstrated that eosinophil-associated processes underlie some of the differences in clinical presentation among patients with Loa loa infection prior to therapy and that some posttreatment adverse events appear to be dependent on eosinophil activation. METHODS: We first conducted a retrospective review of 204 patients (70 microfilaria [MF] positive/134 negative) with Loa loa both before and following definitive therapy. We then measured filarial-specific antibodies, eosinophil- and Th2-associated cytokines, and eosinophil granule proteins in their banked serum prior to and at 1 year following definitive treatment. We also evaluated the influence of pretreatment corticosteroids and/or apheresis in altering the efficacy of treatment. RESULTS: Patients without circulating microfilariae (MF negative) not only had a higher likelihood of peripheral eosinophilia and increased antifilarial antibody levels but also had significantly increased concentrations of granulocyte-macrophage colony-stimulating factor, interleukin (IL) 5, and IL-4 compared with MF-positive patients. However, these differences had all resolved by 1 year after treatment, when all parameters approached the levels seen in uninfected individuals. Neither pretreatment with corticosteroids nor apheresis reduced the efficacy of the diethylcarbamazine used to treat these subjects. CONCLUSIONS: Our results highlight that, by 1 year following treatment, infection-associated immunologic abnormalities had resolved in nearly all patients treated for loiasis, and pretreatment corticosteroids had no influence on the resolution of the immunologic perturbations nor on the efficacy of diethylcarbamazine as a curative agent in loiasis. CLINICAL TRIALS REGISTRATION: NCT00001230.

A Randomized, Placebo-controlled, Double-blind Pilot Study of Single-dose Humanized Anti-IL5 Antibody (Reslizumab) for the Reduction of Eosinophilia Following Diethylcarbamazine Treatment of Loa loa Infection.

BACKGROUND: Diethylcarbamazine citrate (DEC) treatment of loiasis is complicated by adverse reactions that are correlated with the number of circulating microfilariae (mf). The cause of these reactions is unknown, but they are accompanied by a dramatic interleukin-5 (IL-5)-dependent increase in eosinophilia and evidence of eosinophil activation. METHODS: To explore the role of IL-5 driven eosinophilia in post-DEC reactions, 8 adults with confirmed loiasis and <5000 mf/mL blood were enrolled in a randomized, double-blind, placebo-controlled trial of the humanized anti-IL-5 antibody, reslizumab, (1.0 mg/kg IV) administered 3 to 7 days prior to initiation of DEC treatment (9 mg/kg/day for 21 days). The primary endpoint was the reduction in absolute eosinophil count (AEC) during the first week of DEC treatment. RESULTS: Baseline characteristics were comparable between the two groups. Single dose reslizumab lowered the AEC by 77% prior to initiation of DEC therapy (vs. 12% in the placebo group, P < .05). More importantly, AEC remained below baseline in the first week of DEC treatment in all subjects who received reslizumab and in none of the placebo subjects. Mf clearance occurred within 2 days of initiation of DEC in all 7 mf-positive subjects. Mild to moderate adverse events were seen in all 8 subjects and were not significantly different between the groups. CONCLUSIONS: In summary, although reslizumab was able to blunt peripheral eosinophilia post-DEC treatment in subjects with loiasis and had no effect on microfilarial clearance, the reduction in AEC appeared to have been insufficient to prevent post-treatment AEs.

Feasibility of Onchocerciasis Elimination Using a "Test-and-not-treat" Strategy in Loa loa Co-endemic Areas.

BACKGROUND: Mass drug administration (MDA) with ivermectin is the main strategy for onchocerciasis elimination. Ivermectin is generally safe, but is associated with serious adverse events in individuals with high Loa loa microfilarial densities (MFD). Therefore, ivermectin MDA is not recommended in areas where onchocerciasis is hypo-endemic and L loa is co-endemic. To eliminate onchocerciasis in those areas, a test-and-not-treat (TaNT) strategy has been proposed. We investigated whether onchocerciasis elimination can be achieved using TaNT and the required duration. METHODS: We used the individual-based model ONCHOSIM to predict the impact of TaNT on onchocerciasis microfilarial (mf) prevalence. We simulated precontrol mf prevalence levels from 2% to 40%. The impact of TaNT was simulated under varying levels of participation, systematic nonparticipation, and exclusion from ivermectin resulting from high L loa MFD. For each scenario, we assessed the time to elimination, defined as bringing onchocerciasis mf prevalence below 1.4%. RESULTS: In areas with 30% to 40% precontrol mf prevalence, the model predicted that it would take between 14 and 16 years to bring the mf prevalence below 1.4% using conventional MDA, assuming 65% participation. TaNT would increase the time to elimination by up to 1.5 years, depending on the level of systematic nonparticipation and the exclusion rate. At lower exclusion rates (≤2.5%), the delay would be less than 6 months. CONCLUSIONS: Our model predicts that onchocerciasis can be eliminated using TaNT in L loa co-endemic areas. The required treatment duration using TaNT would be only slightly longer than in areas with conventional MDA, provided that participation is good.

Pulmonary Eosinophilic Granulomatosis with Polyangiitis Has IgG4 Plasma Cells and Immunoregulatory Features.

The immunologic mechanisms promoting eosinophilic granulomatosis with polyangiitis (EGPA) are unclear. To characterize the mechanisms underlying pulmonary EGPA, we examined and compared EGPA paraffin-embedded lung biopsies with normal lung biopsies, using immunostaining, RNA sequencing, and RT-PCR. The results revealed novel type 2 as well as immuneregulatory features. These features included basophils and increased mast cell contents; increased immunostaining for tumor necrosis factor ligand superfamily member 14; sparse mast cell degranulation; numerous forkhead box protein P3 (FoxP3)+ regulatory T cells and IgG4 plasma cells; and abundant arachidonate 15-lipoxygenase and 25-hydroxyvitamin D-1 α hydroxylase, mitochondrial. Significantly decreased 15-hydroxyprostaglandin dehydrogenase [NAD(+)], which degrades eicosanoids, was observed in EGPA samples. In addition, there was significantly increased mRNA for chemokine (C-C motif) ligands 18 and 13 and major collagen genes, IgG4-rich immune complexes coating alveolar macrophages, and increased immunostaining for phosphorylated mothers against decapentaplegic homolog 2/SMAD2, suggesting transforming growth factor-ß activation. These findings suggest a novel self-promoting mechanism of activation of alveolar macrophages by arachidonate 15-lipoxygenase-derived eicosanoids to express chemokines that recruit a combined type 2/immunoregulatory immune response, which produces these eicosanoids. These results suggest that the pulmonary EGPA immune response resembles the immune response to a tissue-invasive parasite infection.

Efficacy and safety of mepolizumab in hypereosinophilic syndrome: A phase III, randomized, placebo-controlled trial.

BACKGROUND: Anti-IL-5 therapy is a potential treatment for patients with hypereosinophilic syndrome (HES), although its clinical efficacy is unclear. OBJECTIVE: We sought to investigate the clinical efficacy and safety of mepolizumab versus placebo in patients with HES. METHODS: This randomized, multicenter, double-blind, placebo-controlled, phase III trial was conducted across 39 centers in 13 countries. Eligible patients had FIP1L1-PDGFRA-negative HES, experienced 2 or more flares (worsening of HES-related symptoms or blood eosinophil count requiring therapeutic escalation) in the previous 12 months, and had a screening blood eosinophil count greater than or equal to 1000 cells/µL. Patients were randomized (1:1) to subcutaneous mepolizumab (300 mg) or placebo every 4 weeks for 32 weeks, plus existing HES therapy. The primary outcome was the proportion of patients with 1 or more flares (worsening of HES-related symptoms necessitating therapy escalation or ≥2 courses of blinded rescue oral corticosteroids) during the study; in addition, patients who withdrew early from the study were counted as having a flare. Safety end points were also assessed. RESULTS: The proportion of patients experiencing 1 or more flares/withdrawing from the study was 50% lower with mepolizumab versus placebo (15 of 54 [28%] vs 30 of 54 [56%]; P = .002). Logistic regression analysis was consistent with the primary analysis (odds ratio, 0.28; 95% CI, 0.12-0.64; P = .003). Similar proportions of patients in the mepolizumab and placebo groups experienced on-treatment adverse events (48 of 54 [89%] vs 47 of 54 [87%]). CONCLUSIONS: Compared with placebo, mepolizumab significantly reduced the occurrence of flares in patients with HES, with no new safety signals identified.

A Test-and-Not-Treat Strategy for Onchocerciasis Elimination in Loa loa-coendemic Areas: Cost Analysis of a Pilot in the Soa Health District, Cameroon.

BACKGROUND: Severe adverse events after treatment with ivermectin in individuals with high levels of Loa loa microfilariae in the blood preclude onchocerciasis elimination through community-directed treatment with ivermectin (CDTI) in Central Africa. We measured the cost of a community-based pilot using a test-and-not-treat (TaNT) strategy in the Soa health district in Cameroon. METHODS: Based on actual expenditures, we empirically estimated the economic cost of the Soa TaNT campaign, including financial costs and opportunity costs that will likely be borne by control programs and stakeholders in the future. In addition to the empirical analyses, we estimated base-case, less intensive, and more intensive resource use scenarios to explore how costs might differ if TaNT were implemented programmatically. RESULTS: The total costs of US$283 938 divided by total population, people tested, and people treated with 42% coverage were US$4.0, US$9.2, and US$9.5, respectively. In programmatic implementation, these costs (base-case estimates with less and more intensive scenarios) could be US$2.2 ($1.9-$3.6), US$5.2 ($4.5-$8.3), and US$5.4 ($4.6-$8.6), respectively. CONCLUSIONS: TaNT clearly provides a safe strategy for large-scale ivermectin treatment and overcomes a major obstacle to the elimination of onchocerciasis in areas coendemic for Loa loa. Although it is more expensive than standard CDTI, costs vary depending on the setting, the implementation choices made by the institutions involved, and the community participation rate. Research on the required duration of TaNT is needed to improve the affordability assessment, and more experience is needed to understand how to implement TaNT optimally.

A Test-and-Not-Treat Strategy for Onchocerciasis in Loa loa-Endemic Areas.

BACKGROUND: Implementation of an ivermectin-based community treatment strategy for the elimination of onchocerciasis or lymphatic filariasis has been delayed in Central Africa because of the occurrence of serious adverse events, including death, in persons with high levels of circulating Loa loa microfilariae. The LoaScope, a field-friendly diagnostic tool to quantify L. loa microfilariae in peripheral blood, enables rapid, point-of-care identification of persons at risk for serious adverse events. METHODS: A test-and-not-treat strategy was used in the approach to ivermectin treatment in the Okola health district in Cameroon, where the distribution of ivermectin was halted in 1999 after the occurrence of fatal events related to L. loa infection. The LoaScope was used to identify persons with an L. loa microfilarial density greater than 20,000 microfilariae per milliliter of blood, who were considered to be at risk for serious adverse events, and exclude them from ivermectin distribution. Active surveillance for posttreatment adverse events was performed daily for 6 days. RESULTS: From August through October 2015, a total of 16,259 of 22,842 persons 5 years of age or older (71.2% of the target population) were tested for L. loa microfilaremia. Among the participants who underwent testing, a total of 15,522 (95.5%) received ivermectin, 340 (2.1%) were excluded from ivermectin distribution because of an L. loa microfilarial density above the risk threshold, and 397 (2.4%) were excluded because of pregnancy or illness. No serious adverse events were observed. Nonserious adverse events were recorded in 934 participants, most of whom (67.5%) had no detectable L. loa microfilariae. CONCLUSIONS: The LoaScope-based test-and-not-treat strategy enabled the reimplementation of community-wide ivermectin distribution in a heretofore "off limits" health district in Cameroon and is a potentially practical approach to larger-scale ivermectin treatment for lymphatic filariasis and onchocerciasis in areas where L. loa infection is endemic. (Funded by the Bill and Melinda Gates Foundation and others.).

Dexpramipexole as an oral steroid-sparing agent in hypereosinophilic syndromes.

Hypereosinophilic syndromes (HESs) are a heterogeneous group of disorders characterized by peripheral eosinophilia and eosinophil-related end organ damage. Whereas most patients respond to glucocorticoid (GC) therapy, high doses are often necessary, and side effects are common. Dexpramipexole (KNS-760704), an orally bioavailable synthetic aminobenzothiazole, showed an excellent safety profile and was coincidentally noted to significantly decrease absolute eosinophil counts (AECs) in a phase 3 trial for amyotrophic lateral sclerosis. This proof-of-concept study was designed to evaluate dexpramipexole (150 mg orally twice daily) as a GC-sparing agent in HESs. Dual primary end points were (1) the proportion of subjects with ≥50% decrease in the minimum effective GC dose (MED) to maintain AEC <1000/µL and control clinical symptoms, and (2) the MED after 12 weeks of dexpramipexole (MEDD) as a percentage of the MED at week 0. Out of 10 subjects, 40% (95% confidence interval [CI], 12%, 74%) achieved a ≥50% reduction in MED, and the MEDD/MED ratio was significantly <100% (median, 66%; 95% CI, 6%, 98%; P = .03). All adverse events were self-limited, and none led to drug discontinuation. Affected tissue biopsy samples in 2 subjects showed normalization of pathology and depletion of eosinophils on dexpramipexole. Bone marrow biopsy samples after 12 weeks of dexpramipexole showed selective absence of mature eosinophils in responders. Dexpramipexole appears promising as a GC-sparing agent without apparent toxicity in a subset of subjects with GC-responsive HESs. Although the exact mechanism of action is unknown, preliminary data suggest that dexpramipexole may affect eosinophil maturation in the bone marrow. This study was registered at www.clinicaltrials.gov as #NCT02101138.

Advances in eosinophilic diseases in 2018.

Interest in eosinophil biology and eosinophilic diseases is increasing, as reflected in a doubling of the number of annual articles focused on this topic published in the Journal of Allergy and Clinical Immunology over the past decade. Although the majority of these publications relate to eosinophilic asthma, a growing proportion of them focus on breakthroughs in the diagnosis, treatment, and pathogenesis of other eosinophilic disorders, most notably eosinophilic esophagitis. This review highlights advances in our understanding of eosinophilia and eosinophilic disorders (excluding asthma) published in the Journal in 2018.