Early Treatment Response to Mepolizumab Predicts Clinical Remission in Severe Eosinophilic Asthma.

BACKGROUND

Mepolizumab can induce an early response and clinical remission in people with severe eosinophilic asthma (SEA).

OBJECTIVE

To find whether early response to mepolizumab (100 mg) could predict future asthma remission and to identify the best predictor of treatment response to mepolizumab for achieving remission.

METHODS

The Australian Mepolizumab Registry was used to investigate the early response to mepolizumab at 3 and 6 months and relate this to clinical remission at 12 months. Treatment response was assessed using the 5-item Asthma Control Questionnaire (ACQ-5), oral corticosteroid (OCS) dose, exacerbation frequency, and postbronchodilator FEV. Clinical remission, assessed at 12 months, was defined as an ACQ-5 score less than or equal to 1.0 at 12 months, no exacerbations in the previous 6 months, and no OCS use for asthma in the previous 6 months. We estimated the optimism-corrected area under the curve for internal validation.

RESULTS

We analyzed 255 participants with SEA. Seventy-eight (30.6%) participants achieved clinical remission at 12 months. A prediction model including ACQ-5 score, exacerbation frequency, OCS dose, and postbronchodilator FEV at 6 months was more predictive of achieving remission than measures at 3 months. The ACQ-5 score at 6 months had the highest optimism-corrected area under the curve of 0.778 (95% CI, 0.719-0.833). An ACQ-5 score less than 1.5 at 6 months had a sensitivity of 85.9% for achieving clinical remission, whereas an ACQ-5 score less than 0.75 had a specificity of 84.7%.

CONCLUSIONS

The ACQ-5 score at 6 months was the best predictor of achieving clinical remission at 12 months in people with SEA treated with mepolizumab. These results can be used to design a treat-to-target paradigm for asthma, in which treatment response is assessed at 6 months to predict clinical remission.