Development of the Asthma Control Composite outcome measure to predict omalizumab response.

Background: Previous assessments of response to omalizumab were based on diary-based data rather than standard validated instruments. A composite instrument that translates diary-based data into standard validated asthma control measures would characterize patient response to treatment in terms of current asthma control definitions.

Objective: To develop the Asthma Control Composite (ACC) tool, using real-time diary-based data to predict treatment response in terms of asthma control.

Methods: The ACC tool was derived retrospectively using pooled data from two phase 3 studies in patients with moderate to severe allergic asthma. Patients were randomized to receive subcutaneous omalizumab or placebo for 16 weeks plus stable beclomethasone dipropionate therapy, followed by a 3-month corticosteroid reduction period and 5-month double-blind safety extension. Control was assessed as "complete," "good," or "not controlled," based on a composite score of 4 elements: rescue medication (puffs/day), total asthma symptom score, average number of awakening nights/28 days, and activity limitation.

Results: The ACC was mapped to standard validated measures of patient-reported outcomes, with results consistent with clinical outcomes. The proportion of patients with baseline uncontrolled asthma achieving "good" or "complete" asthma control was 48% with omalizumab and 32% with placebo at approximately 4 months. The mean composite score also was improved with omalizumab (3.52) vs placebo (2.56) at approximately 4 months.

Conclusions: The ACC tool accurately reflects asthma control in moderate to severe asthma patients eligible for biological therapy. Unlike the ACT, which has not been validated in this patient population, the ACC shows promise as an asthma control assessment tool in patients with moderate to severe asthma.