A patient with severe persistent asthma is poorly controlled despite high-dose inhaled corticosteroids (ICS) and a long-acting beta2-agonist (LABA). They have had two exacerbations requiring oral corticosteroids in the past year. Blood eosinophils are 450 cells/µL. FeNO is 55 ppb. Which of the following treatments, according to NICE TA565, would be an appropriate next step to consider?