Combination Biologic Therapy with Mepolizumab and Dupilumab for Severe Eosinophilic Granulomatosis with Polyangiitis and Chronic Rhinosinusitis with Nasal Polyp.

We report the case of a 55-year-old female with eosinophilic granulomatosis with polyangiitis and chronic rhinosinusitis with nasal polyp. Rhinosinusitis recurred 6 months after full-house endoscopic sinus surgery. Although conventional treatment with azathioprine and mepolizumab with steroids was given, it was difficult to simultaneously control both rhinosinusitis and eosinophilic granulomatosis with polyangiitis. Clinical examinations showed polyps in the olfactory cleft, and the patient's anosmia gradually became persistent. Even after administering mepolizumab for a certain period of time, symptoms did not improve, but when the biologic agent was switched to dupilumab, an improvement in recalcitrant chronic rhinosinusitis with nasal polyp was observed. While dupilumab was administered intermittently for refractory chronic rhinosinusitis with nasal polyp, the rhinosinusitis improved and symptoms such as worsening of eosinophilic granulomatosis with polyangiitis paresthesia were observed. Both symptoms gradually subsided 19 months after starting intermittent administration, leading to the discontinuation of dupilumab administration. Rhinosinusitis in the setting of eosinophilic granulomatosis with polyangiitis may be refractory in some cases, and this case provides findings demonstrating the strong effect of dupilumab on eosinophilic inflammation.