Success of an Oral Corticosteroid Withdrawal Pathway for Severe Asthma Patients on Biologics

Background: Biologic medications for severe asthma enable maintenance oral corticosteroid (mOCS) reduction or cessation for many patients. However, there is a small risk of emergent adrenal insufficiency in patients withdrawing from mOCS, and little consensus about how to monitor or avoid this. Aim: Assess the success rate of a bespoke formal mOCS withdrawal pathway for severe asthma patients on biologics. Methods: Patients on mOCS and biologics, who had reduced mOCS to 5mg Prednisolone daily, entered the mOCS withdrawal pathway. Prednisolone was further reduced by 1mg every 6 weeks to 3mg daily then serum cortisol was checked. Patients with cortisol ≥25 nmol/L followed a 20-week prednisolone weaning plan until mOCS cessation and had cortisol re-checked 12 weeks after cessation. Patients with cortisol below 25 nmol/L were referred for endocrinology assessment and not included. Patients received education about adrenal insufficiency symptoms and 'sick day rules'. Results: 39 patients followed the pathway. 33 patients (85%) successfully weaned off mOCS, and 6 patients were unable to. In successfully weaned patients mean (SD) cortisol on 3mg Prednisolone was 244 (162) nmol/L, rising to 317 (119) nmol/L 12 weeks after completion of weaning (p=0.01). In 6 patients who failed to wean, mean (SD) cortisol on 3mg Prednisolone was 107 (94) nmol/L. Reasons for weaning failure were symptoms of adrenal insufficiency or cortisol <25 nmol/L at 12 weeks after mOCS cessation. These patients remain on 2-5mg of Prednisolone. There were no serious adverse events. Conclusion: Our pathway facilitated successful withdrawal of mOCS in 85% of patients with cortisol ≥25 nmol/L on 3mg Prednisolone, with no adverse events.