• J Mark FitzGerald, Louis-Philippe Boulet, and Richard M A Follows.
• Respiratory Division, Vancouver General Hospital, Vancouver, BC, Canada. markf@interchange.ubc.ca
• Clin Ther. 2005 Apr 1;27(4):393-406.

BackgroundA patient-driven, adjustable maintenance dosing (AMD) approach to asthma therapy, in which the dose is adjusted by patients according to the severity of their symptoms, has recently been compared with fixed-dose therapy in open-label studies.ObjectiveThis study used a double-blind, double-dummy design to compare the efficacy of 2 treatment approaches: stable dosing of salmeterol/fluticasone propionate (SAL/FP) and AMD of formoterol/budesonide (FOR/BUD).MethodsThis was a 1-year, multicenter, randomized, double-blind, double-dummy study in adult patients with symptomatic asthma that was not controlled by therapy with 200 to 500 microg/d inhaled corticosteroid (ICS) plus a long-acting beta2 agonist, or with >500 to 1000 microg/d ICS alone. Patients were randomized to receive 1 inhalation of SAL/FP 50/250 microg BID or 2 inhalations of FOR/BUD 6/200 microg BID, both delivered via dry powder inhaler devices. After 4 weeks of stable dosing in both groups, eligible patients continued the study for an additional 48 weeks, receiving either a stable dose of SAL/FP or AMD of FOR/BUD. According to the AMD treatment plan, patients initially halved their dose and subsequently stepped up or down as indicated by the presence or absence of nocturnal awakenings due to asthma, frequency of rescue medication use, and changes in morning peak expiratory flow (PEF). The primary end point was the percentage of symptom-free days. Other parameters included daily asthma symptom scores, morning PEF, percentage of days free of rescue medication use, daily rescue medication use, percentage of nighttime awakenings due to asthma, percentage of weeks with well-controlled asthma, and number of exacerbations requiring oral corticosteroids or emergency department (ED) visits/hospitalizations. Tolerability was assessed in terms of adverse events spontaneously reported or elicited at clinic visits.ResultsThe intent-to-treat population comprised 688 patients (344 per treatment arm) with a mean age of 45 years and a mean baseline forced expiratory volume in 1 second 81% of the predicted normal value. After 4 weeks' stable dosing, 581 patients (295 SAL/FP, 286 FOR/BUD) continued beyond visit 3 into the remaining 48-week treatment period. Over weeks 1 through 52, patients receiving stable dosing of SAL/FP had a significantly greater percentage of symptom-free days compared with those receiving AMD of FOR/BUD (median, 58.8% vs 52.1%, respectively; P = 0.034). The incidence of asthma exacerbations requiring oral steroids or an ED visit/hospitalization was 47% lower with SAL/FP compared with FOR/BUD (adjusted annual mean rate, 0.18 vs 0.33; P = 0.008). During weeks 5 through 52, patients in the FOR/BUD AMD group used a mean of 1.8 inhalations/d (equivalent to BUD 360 microg/d), and 235 (82.2%) patients stepped down to 1 inhalation/d. Mean (SD) daily ICS exposure over 52 weeks was 463 (81) microg FP and 480 (238) microg BUD in the respective treatment arms.ConclusionsIn this adult population with persistent asthma, stable dosing of SAL/FP 50/250 microg BID resulted in significantly greater increases in symptom-free days, days free of rescue medication, and morning PEE, as well as almost halving the exacerbation rate, compared with AMD of FOR/BUD 6/200 microg. The results suggest that there is a minimum daily amount of maintenance therapy necessary to prevent exacerbations in adults with persistent asthma.

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