Tezepelumab in eosinophilic granulomatosis with polyangiitis (EGPA)

<bold>Background:</bold> EGPA is a multisystemic inflammatory disease characterised by eosinophilic tissue infiltration. Thymic stromal lymphopoietin (TSLP) is an epithelium‐derived cytokine that activates the eosinophil in both innate and adaptive immune responses. TSLP gene polymorphism is associated with the risk of developing EGPA, patients with EGPA have elevated levels of TSLP. The monoclonal antibody tezepelumab binds to TSLP and improves disease control in eosinophilic diseases such as severe eosinophilic asthma (SEA). To date there are no published reports of tezepelumab in EGPA. We report the response in 2 patients with refractory EGPA. <bold>Methods:</bold> Measures of EGPA activity were performed at initiation and after 6 months including Birmingham Vasculitis Activity Score (BVAS), Asthma Control Questionnaire (ACQ)-6 , maintenance oral corticosteroid dose (mOCS), spirometry, and fraction of exhaled nitric oxide (FeNO). <bold>Results:</bold> Patient 1 (male; aged 36) was on anti-IL5/5R therapy for 19 months prior to starting tezepelumab. At initiation BVAS was 2.8, ACQ-6 5.6 and mOCS dose 12 (±2.3) mg/day. After 6 months of tezepelumab BVAS improved to 0, ACQ-6 to 0.2 and mOCS to 4 mg/d. FEV1 improved from 2.61 L (64%) to 3.51 L (86%), FeNO from 61 to 24 ppb. Patient 2 (female, aged 43) was on anti-IL5R for 30 months prior to tezepelumab. At initiation, BVAS was 5, ACQ-6 3.66 and mOCS dose 22 (±24) mg/day. After 6 months BVAS improved to 1.3, ACQ-6 to 1.83, and she was able to stop mOCS. FEV1 improved from 1.69 L (60%) to 2.07 L (85%) and FeNO from 171 to 70 ppb. Neither experienced an EGPA relapse. <bold>Conclusion:</bold> In a first ever report of tezepelumab use in EGPA, we describe clinically important improvements in two patients with refractory EGPA.