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Are we prescribing asthma biologics appropriately in the US?

Published: August 2, 2022

Current Global Initiative for Asthma (GINA) guidelines recommend a stepwise approach to asthma treatment, with assessment of symptom control alongside inhaler technique and adherence. In patients on maximum maintenance ICS/LABA with or without a LAMA that are still experiencing asthma exacerbations, escalation of treatment to biologics is recommended. A study of US administrative claims data showed that 14% of patients had non-biologic therapy escalation within a year of starting a long-term ICS regimen but after the escalation year, 41% of patients still had uncontrolled asthma, and 21% had at least one exacerbation. Poor medication adherence, access to medications, and lack of maintenance therapy efficacy are potential causes of poor treatment effectiveness. The aim of this study was to describe the clinical status of patients with asthma in the US who were escalated to biologic therapy by examining claims-based adherence to maintenance medication.

This retrospective observational study published by Bender in The Journal of Allergy and Clinical Immunology: In Practice used a real world Electronic Medical Record database to assess adult asthma patients between January 2016 and June 2020. Biologic use was identified using medical and pharmacy claims for omalizumab, mepolizumab, reslizumab, benralizumab, and dupilumab. Patients were excluded if they had 2 or more claims separated by at least 60 days, or had a diagnosis of chronic obstructive pulmonary disease, chronic idiopathic urticaria, eczema, or nasal polyps at any time during the study period. Two sets of criteria for defining uncontrolled asthma were used, the European Respiratory Society and American Thoracic Society (ERS/ATS) and Stempel et al. criteria; these criteria considered lung function, Asthma Control Test [ACT], Asthma Control Questionnaire [ACQ]) and healthcare utilization measures (ED visits, hospitalizations, reliever medication use). GINA Step prior to biologic initiation was inferred for all patients by using recorded prescription claims and GINA treatment step definitions. Adherence to maintenance medication was assessed in patients who received ICS, ICS-LABA, LABA, LAMA, xanthines, LTRA, or ICS-LABA-LAMA asthma maintenance therapy in the 12 months prior to biologic initiation. Adherence was measured as ‘proportion of days covered’ (PDC), calculated as the ratio of days the patient was supplied with at least one maintenance medication during the assessment period to the total assessment duration (12 months). A PDC of <80% was considered suboptimal adherence.

During the 12 months prior to biologic initiation, 403 (80%) of the 506 patients who were escalated to biologics received ICS, ICS-LABA, LABA, LAMA, xanthines, LTRA, or ICS-LABA-LAMA asthma maintenance therapy. PDC was calculated only amongst these 403 patients, as including patients without those specific maintenance medication claims would skew the data. At a PDC threshold of <80%, 63% (n=255) of these patients were considered to have suboptimal adherence to their maintenance medication during this period, and the mean PDC over the 12 months was 59%. The proportions of patients not achieving targeted adherence thresholds of PDC <70% was 55%; PDC <60% was 50%; and PDC <50% was 43%. Adherence assessed for patients at GINA Steps 4/5 showed that 57% of patients had suboptimal adherence, and 50%, 44% and 37% had <70%, <60% and <50% PDC, respectively. Analysis of adherence and control level during the 12 months before escalation to biologics showed that, of the patients with suboptimal adherence (PDC <80%), 156 patients (61%) had uncontrolled asthma according to the ERS/ATS criteria and 196 patients (77%) using the Stempel criteria. For patients with PDC ≥80%, ERS/ATS and Stempel criteria showed that 74% and 92% were uncontrolled before biologic initiation, respectively. Medication adherence during the 12 months prior to biologic initiation was assessed in 54 patients with chronic OCS use. Of these patients, 39% had suboptimal adherence (PDC <80%), 35% had PDC <70%, 26% had PDC <60%, and 17% had PDC <50%. Of the patients in this population at GINA Step 4/5 (n=44), the proportions of patients who had PDC <80%, <70%, <60% and <50% were 32%, 32%, 20% and 9%, respectively.  

The results of this study demonstrate that approximately two-thirds of patients who were initiated on biologics had suboptimal adherence to maintenance medication in the 12 months prior to escalation. Approximately one-third of the patients who were escalated to biologic therapy would be considered to have mild asthma based on the GINA guidelines. In addition, patients who were at an appropriate pre-escalation GINA Step 4/5 level were not fully adherent to their maintenance medication. Therefore, incorporating objective monitoring of patient medication adherence into existing guidelines may help reduce inappropriate escalation to biologic therapies to achieve asthma control.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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