Dupilumab suppresses relapsing chronic eosinophilic pneumonia with severe asthma.

Dupilumab-induced hypereosinophilia is mediated by blockade of the IL-4/IL-13 pathway, which reduces eosinophil migration from peripheral blood. The increase in peripheral blood eosinophils may lead to chronic eosinophilic pneumonia (CEP) and/or eosinophilic granulomatosis with polyangiitis, but a direct causal connection between dupilumab and eosinophilic lung diseases has not been established. A 33-year-old Japanese woman with bronchial asthma since age three was treated with fluticasone propionate plus salmeterol twice daily after several asthma exacerbations at age 17. Her course was complicated by CEP at age 33 which resolved without the need for systemic steroids. However, in the four months following resolution of her CEP, the patient had three asthma exacerbations, and a recurrence of CEP, with blood leukocytes of 8500/µL, of which 25.0% were eosinophils. She was treated with prednisolone 50 mg/day, but she could not continue this dose due to the onset of myalgia. Then she had relapsing CEP twice within three months. She was treated with prednisolone 15 mg/day for CEP, but she had persistent asthma for more than one month; dupilumab was added at 600 mg, followed by 300 mg every two weeks. In the first month of treatment with dupilumab, the patient's asthma symptoms resolved completely, and she had only one relapse of CEP. In 12 months of follow-up, she had neither an asthma exacerbation nor another relapse of CEP. Dupilumab may be a promising treatment for patients with refractory asthma complicated by recurring CEP and undesirable steroid side effects.