The response to combination therapy treatment regimens in severe/difficult-to-treat asthma.

The aim of the present study was to assess the response of high-dose salmeterol/fluticasone combination (SFC) and low-dose SFC compared with regimens without inhaled corticosteroid (ICS) plus long-acting beta-agonist (LABA) in a large cohort with severe or difficult-to-treat asthma. Subjects were administered low-dose SFC (100/50 or 250/50 microg) or high-dose SFC (500/50 microg), and a control group received medications that could include ICS or LABA but not both. The present authors calculated unadjusted and propensity score-adjusted differences in outcomes consistent with components of asthma control, comparing high-dose and low-dose SFC cohorts with controls. The low-dose SFC cohort had higher asthma-related quality of life and fewer asthma control problems compared with controls. The high-dose SFC cohort had higher forced expiratory volume in one second but higher odds of having severe asthma compared with controls. The present results support the evidence that some asthmatics achieve better outcomes while receiving a low-dose salmeterol/fluticasone combination, but also suggest that those on a high-dose salmeterol/fluticasone combination fail to achieve significant improvement in many control-related health outcomes as compared with similar patients not receiving salmeterol/fluticasone combination. These findings suggest a limited value of high-dose salmeterol/fluticasone combination compared with the alternatives. While additional studies are needed, the present findings call for alternative therapeutic approaches in severe/difficult-to-treat asthma for those unable to attain asthma control with or without salmeterol/fluticasone combination.