Single-inhaler triple therapy improves adherence among patients with asthma
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Patients with asthma who began triple therapy with a single inhaler had better adherence than patients on triple therapy with multiple inhalers, according to a study published in The Journal of Allergy and Clinical Immunology: In Practice.
Yet, overall, adherence and persistence remained relatively low, indicating a need for better patient education, William W. Busse, MD, honorary associate and fellow in the department of medicine, division of allergy, pulmonary and critical care at University of Wisconsin School of Medicine and Public Health, and colleagues wrote in the study.
Maintenance treatment for asthma may include triple therapy with 100 µg fluticasone furoate, an inhaled corticosteroid; 62.5 µg umeclidinium, a long-acting muscarinic antagonist; and 25 µg vilanterol, a long-acting beta-2 adrenergic agonist, taken via multiple-inhaler triple therapy, or via single inhaler triple therapy (SITT) once daily, based on the FDA approval of the Trelegy Ellipta dry powder inhaler (GlaxoSmithKline) in 2017 for COPD and 2020 for asthma.
The retrospective, weighted cohort study examined data from the IQVIA PharMetrics Plus database recorded between Sept. 18, 2016, and Dec. 31, 2019, of patients aged 18 years and older with at least one diagnosis of asthma during the baseline period.
The study included 1,396 patients (mean age, 50.6 years; 63.8% female) on SITT therapy and 5,115 patients (mean age, 50.2 years; 64.5% female) on MITT therapy.
Researchers evaluated treatment adherence — measured by the proportion of days covered (PDC) —at 3, 6 and 12 months, as well as persistence, assessed by the time to discontinuation of SITT or MITT, with nonpersistence defined as a gap of at least 45 days.
At 3 months, patients initiated on SITT had a significantly higher mean PDC than users initiated on MITT (0.68 vs 0.59; adjusted mean difference [aMD], 0.09; 95% CI, 0.06-0.13). This improvement continued at 6 months (0.56 vs. 0.46; aMD, 0.1; 95% CI, 0.05-0.14) and at 12 months (0.46 vs. 0.35; aMD, 0.12; 95% CI, 0.07-0.17).
The patients initiated on SITT also were 31% more likely to be adherent (PDC 0.8) than the patients initiated on MITT (40.6% vs. 31.3%; adjusted RR = 1.31; 95% CI, 1.13-1.54).
SITT users also were 51% more likely to be adherent at 6 months (30.9% vs. 20.4%; aRR = 1.51; 95% CI, 1.23-1.81) and twice as likely at 12 months (24.7% vs. 12.9%; aRR = 2.01; 95% CI, 1.61-2.6) compared with MITT users.
When it came to persistence, median duration of treatment was 131 days among SITT users and 66 days among MITT users. The patients who initiated SITT also were 49% more likely to persist at 12 months than those on MITT (25.9% vs. 15.1%; adjusted HR = 1.49; 95% CI, 1.39-1.6).
The researchers attributed the greater adherence and persistence among SITT users to the therapy’s once-daily use overcoming the complexities of using multiple inhalers with different dosing regimens in MITT therapy.
Further, the researchers speculated that the better adherence and persistence among the SITT users may lead to improved clinical outcomes, with well-established associations between adherence and asthma management and control.
The researchers additionally suggested that better adherence and persistence may yield economic benefits, with lower medical health care costs and asthma-related exacerbation costs among patients with PDC rates of 80% and higher.
Yet the researchers cautioned that adherence and persistence rates among the SITT users were still relatively low and that they decreased during follow-up. Possible causes for these decreases include lifestyle changes, lack of understanding of the benefits of therapy, emotional response to the disease, side effects, mistrust of health care, treatment beliefs and little to no follow-up after initiation of treatment.
The researchers recommended educational programs, electronic monitoring devices and frequent monitoring of adherence and inhaler techniques to improve both adherence and outcomes for patients with asthma. Further studies would be warranted as well, the researchers concluded.
Perspective
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William B. Feldman, MD, DPhil, MPH
Some patients with asthma require maintenance treatment with triple therapy, which includes an inhaled corticosteroid (ICS), a long-acting beta-agonist (LABA) and a long-acting muscarinic antagonist. The important new study by Busse and colleagues finds that patients who receive triple therapy via a single inhaler are more adherent to their regimens than patients who receive triple therapy via two or more inhalers. This work fits within a broader literature on inhaler nonadherence, which consistently finds that patients with asthma do not take their medications as prescribed.
The new study, which underscores the potential benefits of single-inhaler triple therapy, raises a set of questions that merits further research. First, to what extent is nonadherence to multiple-inhaler triple therapy associated with worse clinical outcomes? As the authors highlight, many patients in the multiple-inhaler triple therapy group still received an ICS even after they were considered nonadherent, because nonadherence was defined by the cessation of any inhaler. By contrast, patients in the single-inhaler triple therapy group who were nonadherent were, by definition, off ICS therapy.
Understanding differential clinical outcomes between the two study groups would be a valuable next step. More broadly, further research is needed to understand the many drivers of nonadherence and to develop targeted interventions designed to help patients. Even among those receiving single-inhaler triple therapy in this study with 12 months of follow-up, less than a quarter were adherent.
There are now two brand-name single-inhaler triple therapies on the U.S. market, and each is expensive with patent protection lasting beyond 2030. By contrast, cheaper generic competitors for ICS-LABAs have come onto the market, and further competition for these products will likely reduce prices more in the coming years.
An important question that we must ask in the pulmonary community is how to achieve the benefits of single-agent triple therapy while expediting generic entry and reducing costs. This study represents an important step toward understanding the value of single-inhaler triple therapy. Future work may help provide more context for assessing the magnitude of financial rewards that our health care system ought to bestow on such improvements.
Reference:
Feldman WB, et al. Health Aff (Millwood). 2022;doi:10.1377/hlthaff.2021.01874.
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