More costly combination therapies are significantly over-used in US patients with mild asthma, despite the lack of any apparent clinical benefit and despite guidelines recommending that patients are started on monotherapy with inhaled corticosteroids, a study by the Medco Research Institute has found.

Results from the study were presented at the Annual Scientific Meeting of the American College of Allergy, Asthma & Immunology in Phoenix, Arizona. The Medco Research Institute is the research subsidiary of pharmacy benefit manager Medco Health Solutions.

As Medco observed, inhaled corticosteroids (ICS) are “widely considered the fundamental treatment” for asthma in both adults and children. The US National Asthma Education and Prevention Program and the Global Initiative for Asthma recommend ICS monotherapy as the initial treatment for mild persistent asthma due to its effectiveness in controlling asthma and preventing exacerbations.

Despite this guidance, Medco said, reports suggest physicians treat mild persistent asthma with combinations of ICS and long acting beta agonists (LABAs), such as Advair (fluticasone/salmeterol) and Symbicort (budesonide/formoterol) – an approach traditionally reserved for patients with moderate to severe asthma.

The Medco Health Research analysis compared the medical and pharmacy costs, as well as the clinical outcomes, of mild asthma patients taking ICS monotherapy versus those taking an ICS/LABA combination therapy across different prescriber specialties.

The researchers looked at integrated medical and pharmacy claims for patients with mild asthma who received a single-entity ICS or an ICS/LABA combination therapy between 1 July and 31 December 2008.

Patients also needed to have received at least one additional prescription for the same drug during the following six months to determine costs (adjusted for age, gender and baseline clinical characteristics) and clinical outcomes during one year of follow-up.

Two-thirds on combination therapy

Of the 8,424 patients treated for mild asthma in the study, 5,523 (65.6%) were on an ICS/LABA combination and 2,901 (34.4%) on ICS monotherapy, the researchers found.

There was no significant difference between the two groups in asthma-related medical costs, use of oral steroids, hospitalisations or emergency room visits, indicating that “there was no apparent additional clinical benefit gained” from using combination therapy compared with ICS monotherapy, Medco noted.

There was, however, a substantial cost difference. The study found that asthma-related pharmacy costs for patients on combination ICS/LABA therapy were US$215 higher per patient per year than for the ICS monotherapy group, while asthma-related total healthcare costs were US$264 higher.

The Medco analysis departed from previous studies on the use of ICS/LABA combinations in mild asthma patients in a number of respects, the researchers pointed out.

Lack of comparisons between inhaled corticosteroids other than mometasone furoate and ICS/LABA combinations other than fluticasone/salmeterol was a common limitation in previous studies, they said.

“The fact that this study included mild asthma patients taking any ICS single-agent product versus any ICS/LABA combination product suggests that the economic impact observed is a medication class effect rather than attributed to any single product,” the researchers commented.

Another common drawback with previous studies was the lack of a large mild asthma patient population. “The results from this large patient database strengthen previous findings showing the use of ICS/LABA combination products in mild asthma patients results in significantly higher costs with no apparent clinical benefit,” Medco said.

Updated labelling

In 2010, the US Food & Drug Administration updated the labelling for long-acting beta agonists to stipulate that they should not be used in patients with well-controlled asthma, Medco pointed out.

In patients needing a LABA, once asthma control is achieved and maintained, step-down therapy should begin to eliminate LABA use while the patient continues on ICS treatment, the revised labelling states.  Moreover, LABAs should only be used as additional therapy in patients with uncontrolled asthma currently taking an ICS, Medco noted.