A personalised regimen of tapering oral corticosteroids in the presence of the anti-IL5 receptor α-directed cytolytic monoclonal antibody benralizumab can help to achieve elimination or dose reduction of oral corticosteroids in a large proportion of patients with severe eosinophilic asthma.

A 250 μg dose of adrenocorticotropic hormone (ACTH) dynamic stimulation test was used to assess the degree of impaired adrenal reserve.

However, the 250 μg dose of ACTH is supraphysiologic and will inevitably result in a relatively higher proportion of tests with apparently normal stimulated cortisol levels compared with a more physiological dose of 0·5–1 μg.2

Therefore, the presence of a normal cortisol response after stimulation with 250 μg of ACTH in turn might lull clinicians into a false sense of security in terms of successful oral corticosteroid weaning on benralizumab, when patients might conceivably still be at risk of adrenocortical insufficiency.

In this regard, such patients with severe asthma would also be taking high doses of inhaled corticosteroids, which have a propensity for blunting the stimulated cortisol response even in the absence of oral corticosteroids.

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