A subgroup analysis of the MONICA study: a 12-month, open-label study of add-on montelukast treatment in asthma patients.

Objective: We evaluated montelukast, a leukotriene receptor antagonist (LTRA), added to inhaled corticosteroids (ICS) or ICS+long-acting β₂ agonist (LABA) regimens over a period of 1 year to explore the therapeutic effects on asthma patients in patient subgroups.

Methods: The majority of patients enrolled in this 12-month, open-label study were ≥18 years of age (n = 1681) with mild to moderate asthma insufficiently controlled by ICS or ICS+LABA. Patients received montelukast 10 mg qd as add-on therapy and were evaluated at Months 3, 6, 9, and 12. Asthma Control Test (ACT) score in the overall population was the primary endpoint; ACT score categories range from <16 (uncontrolled) to 25 (completely controlled). A post hoc secondary analysis of the following subgroups was conducted. age (< 30 years, 30-50 years, >50 years), gender, presence of allergic rhinitis, duration of asthma (< 5 years, ≥5 years), and the use of ICS or ICS+LABA.

Results: Over 12 months of therapy, mean ACT scores improved by 5.7 units (p < .0001); at baseline, the mean (SD) ACT score for all patients was 14.6 (4.6) and at Month 12, the mean (SD) ACT score was 20.3 (4.2). The subgroups of patients who had allergic rhinitis and those who were <30 years of age demonstrated numerically better ACT scores compared with those who did not have allergic rhinitis or who were >30 years of age. Additional evaluation of the ACT score categories also demonstrated better control among patients who had duration of asthma <5 years and were treated with ICS without LABA.

Conclusion: Add-on montelukast demonstrated significant improvement in asthma symptoms over 12 months in all patients in the study. Asthma control was improved in all patient subgroups, but comorbid allergic rhinitis, younger age, shorter duration of asthma, and treatment with only ICS and not ICS+LABA were indicators of better control with add-on montelukast. These observations may likely be shared with other antiasthmatic medications and should be further explored.