Clinical efficacy of anti-IL-5 monoclonal antibody mepolizumab in the treatment of eosinophilic otitis media

Abstract

Objective: Eosinophilic otitis media (EOM) is an intractable otitis media characterized by a highly viscous effusion containing eosinophils, and it is mostly associated with bronchial asthma. Recently, anti-IL-5 therapy using mepolizumab has been reported to be effective for patients with severe and refractory eosinophilic bronchial asthma. EOM shows accumulation of eiosinophils in the middle ear effusion and most EOM patients have high numbers of peripheral blood eosinophils. Therefore, we carried out a retrospective study to determine whether anti-IL-5 therapy is also effective in the treatment of EOM.

Patients and methods: Nine patients with EOM associated with bronchial asthma received the anti-IL-5 agent mepoliumab as an add-on therapy for at least 6 months (mepolizumab group). They were evaluated by EOM severity scores, symptom scores, bone conduction hearing levels, and surrogate markers before and after receiving the anti-IL-5 therapy. Thirteen EOM patients associated with bronchial asthma who did not receive the anti-IL-5 therapy were also included as controls (control group).

Results: The severity scores of most patients in the mepolizumab group were dramatically reduced at 3 months after the initiation of this therapy and, as therapy continued, they further decreased to levels significantly lower than the baseline. However, two patients with a granulation type of EOM showed minimal improvement from the therapy. The severity scores of control patients showed no significant changes during the study period. Significant deterioration of the bone conduction hearing levels was not observed in either group. The number of peripheral blood eosinophils was significantly reduced, and eosinophils were scarcely observed in the middle ear effusion and middle ear mucosa after the mepolizumab therapy.

Conclusions: Anti-IL-5 therapy using mepolizumab was effective at inhibiting eosinophilic recruitment to the middle ear in patients with EOM. However, this therapy showed minimal effect on patients with the granulation type of EOM. Therefore, this therapy may be a viable treatment option for refractory EOM without severe mucosal change.

Keywords: Anti-IL-5 therapy; Eosinophilic otitis media; Mepolizumab; Severity score.