A 71-year-old female with severe COPD (FEV₁ 38% predicted) p…

A 71-year-old female with severe COPD (FEV₁ 38% predicted) presents for follow-up. She has chronic bronchitis symptoms and reports two hospitalizations for COPD exacerbations in the past year despite adherence to triple inhaler therapy (fluticasone/umeclidinium/vilanterol). She quit smoking 3 years ago. FEV 1= 42%. Blood eosinophil count is 90 cells/µL. She denies asthma history. Oxygen saturation is 93% on room air. BMI is 21 kg/m². Which of the following is the most appropriate next step in pharmacologic management?