D1.144 - Eosinophilic myocarditis as a complication of dupilumab treatment

T2-targeted biologics are generally considered safe, but side effects can occasionally occur. Dupilumab has been associated with transient hypereosinophilia usually without organ involvement.

A 75-year-old patient with severe eosinophilic uncontrolled asthma and mepolizumab intolerance was scheduled for dupilumab. During initiation of treatment, an increase of blood eosinophils was noted without signs of HES.  After 3 months, he was hospitalised for weakness, muscle pain, fever, dyspnea, and wheezing lasting 3 weeks. Laboratory results confirmed elevated hs-troponin, NTproBNP and CRP with normal procalcitonin and severe eosinophilia (5,45 x 10⁹/L), CT scan revealed bilateral pleural effusions, GGO, micronodules and reactive mediastinal lymphadenopathy. There were no signs of ischemia on ECG, TTE confirmed mild hypokinesis of the inferior myocardial wall and CT coronary angiography excluded significant coronary artery stenosis. Parainfectious myocarditis, pneumonia and asthma exacerbation were suspected. Empirical antibiotic therapy along with systemic corticosteroids (hydrocortisone 100 mg BID) resulted in a  decrease of CRP and blood eosinophils. Tapering of systemic corticosteroids led to the re-increase of inflammation and eosinophilia. The history of dupilumab treatment together with eosinophilia led us to suspect secondary hypereosinophilic syndrome  due to dupilumab treatment. Bronchoscopy, bronchoalveolar lavage and transbronchial cryobiopsy did not confirm eosinophilic pneumonia, but cardiac MRI revealed changes typical for eosinophilic myocarditis. Prednisone was started at a dose of 60 mg/day with taper based on blood eosinophil counts (60 mg/day 1 week, 40 mg/day 2 weeks,  20 mg/day 1 week, 10 mg/day 1 week, 5 mg/day 1 week). The dose of 5 mg/day led to progressive increase of eosinophilia, so the dose of 10 mg/day was maintained. Benralizumab (at the standard asthma dosage) was started, allowed prednisone withdrawal and maintained asthma controlled. Despite good tolerance, the patient refused to continue the treatment. His asthma is now uncontrolled, he has mild eosinophilia and is taking prednisone 2.5 mg/day for granuloma annulare.

Hypereosinophilia and hypereosinophilic syndrome have been previously observed in patients with asthma after dupilumab initiation, therefore, blood eosinophils should be monitored. Awareness of this adverse effect is needed among various medical specialists to facilitate correct and prompt diagnosis and treatment.