{
  "abstract": "Background Occupational asthma (OA) accounts for 16% of adult-onset asthma. OA is overrepresented in severe asthma cohorts, and outcomes in severe OA may be worse than in non- OA particularly where exposures continue. There is limited data on use of biologics in OA, with only one published study on omalizumab. We present real-world data from a single UK centre on biologic use in patients with severe OA.Methods Patients receiving biologic therapy for severe asthma were screened for a diagnosis of OA. OA was diagnosed in a specialist centre with objective evidence of a positive work effect either by serial peak flow analysis and/or specific inhalation challenge. Data collected included demographics, spirometry at diagnosis, biomarkers, causative agent, comorbidities, biologic prescribed, and clinical outcomes. Asthma control was assessed with the Asthma Control Questionnaire.Results Of 335 patients on biologics for severe asthma, 11 (3.3%) had OA. Mean age was 58 years (SD 6.9), and 36% were female ( table 1). None had a prior asthma history, and all exhibited a Th2-high phenotype. None were current smokers; 64% were ex-smokers. Median exposure duration to the causative agent was 10 years (IQR 6–18). Causative agents included; isocyanates (n=3), epoxy resins (n=2), cleaning products (n=3), and wheat flour (n=2). Most patients were prescribed Tezepelumab (n=6) and over 60% had trialled at least 1 biologic. Two discontinued biologics (one due to adverse effects, one by choice), both with ongoing poor asthma control, both patients had already been removed from causative agent. Of the remaining patients, symptom control was evenly split between well-controlled and sub-optimally controlled. Two remained exposed to the causative agent (18%), and fewer than half were still employed.Abstract S116 Table 1Clinical Characteristics of Patients with Severe Occupational Asthma (n = 11) Variable Value Age, years (mean ± SD) 58 ± 6.9 Female sex n,% 4 (36) Smoking status n,% • Current 0 (0) • Ex-smoker 7 (64) • Never 4 (36) Prior asthma n,% 0 (0) History of atopy n,% 8 (73) FEV1, L (mean ± SD) 2.09 ± 0.44 FEV1,% predicted (mean ± SD) 66% ± 8.3 Fractional exhaled nitric oxide (FeNO), ppb (mean ± SD) 71 ± 31 Serum eosinophils, ×109/L (median, IQR) 0.43 (0.30–1.00) Causative agent identified n,%Cleaning productsIsocyanatesEpoxyWheatHydraulic fluid 3 (27)3 (27)2 (18)2 (18)1 (9) Duration of exposure, years (Median, IQR)) 10 (6–19.8) Currently exposed to agent n,% 2 (18) Employment status: employed n,% 5 (45) Current biological therapy n,% • Omalizumab 0 (0) • Mepolizumab 0 (0) • Benralizumab 1 (9) • Dupilumab 1 (9) • Tezepelumab 6 (55) • None 2 (18) Prior biological therapy use n% 0 4 (36) 1 4 (36) 2 2(18) 3 1 (9) Asthma control status n,% • Well-controlled 4 (36) • Sub-optimal 4 (36) • Poor 3 (27) Conclusion Biological therapy offers clinical benefit in patients with severe OA when used alongside standard asthma treatment and exposure control. Isocyanate-related OA was associated with persistent symptoms despite cessation of exposure, suggesting a more treatment-resistant phenotype. Over half were unemployed suggesting poor employment outcomes for severe OA. Further research to explore prevalence of OA among severe asthma and better characterise treatment responses where exposures may continue is important for this underrepresented population.",
  "authors": [
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "S Ali"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK",
        "The University of Manchester, Manchester, UK"
      ],
      "name": "H Badri"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "S Johnson"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "K Ballance"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "E Karpetis"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "M Cheadle"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "T De Souza"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "J Chan"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "R Barraclough"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "T Pantin"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK",
        "The University of Manchester, Manchester, UK"
      ],
      "name": "R Wiggans"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK",
        "The University of Manchester, Manchester, UK"
      ],
      "name": "JL Hoyle"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "NJ Meghani"
    },
    {
      "affiliations": [
        "Manchester University NHS Foundation Trust, Manchester, UK"
      ],
      "name": "N Sehgal"
    }
  ],
  "title": "S116 Biological therapy in severe occupational asthma",
  "uid": "35d67395-93c3-5efc-af54-03971ff0da50"
}