Etanercept therapy for immune-mediated cochleovestibular disorders: a multi-center, open-label, pilot study

Immune-mediated cochleovestibular disorders (IMCVDs) continue to present a diagnostic and therapeutic challenge. Antirheumatic agents, commonly employed for IMCVDs, are associated with variable efficacy and sometimes with serious side effects. The objective of the current study was to preliminarily evaluate the efficacy of etanercept therapy for IMCVD.

In this open-label prospective pilot study, 23 patients with bilateral IMCVDs or symptoms of bilateral Meniere's disease were treated with etanercept (25 mg twice weekly, by subcutaneous injection) for 24 weeks. All participants showed progressive hearing loss within 3 months prior to the study and responded to prednisone therapy. Hearing improvement was defined as an improvement of sensorineural hearing from baseline, in at least one ear, of 15 dB or more in the pure-tone air conduction thresholds, or an increase of more than 12% in word identification score. When present, vertigo and tinnitus were assessed by frequency and severity of attack and a functional level scale. Limited serial positron emission tomography (PET) of the inner ear region was performed in 5 patients to assess disease activity.

There were 12 female (52%) and 11 male patients with a mean age of 48 years. Hearing improved in 7 (30%) patients, was unchanged in 13 (57%), and worsened in 3 (13%). Of 21 patients with tinnitus, this symptom improved in 7 (33%), was unchanged in 10 (48%), and worsened in 3 (13%). Of 16 patients with vertigo, 8 (50%) were improved, 7 (47%) unchanged, and 1 (3%) worse at the end of the study. Etanercept was generally well tolerated. PET was positive on one ear of 2 of 5 patients, remained positive with treatment on 1 of these, and was initially positive in 1 deaf ear, becoming negative at followup.

These prospective pilot data suggest that etanercept therapy is safe among patients with IMCVDs. However, these data do not suggest substantial efficacy of etanercept among patients with IMCVDs in improving hearing loss. There appeared to be stabilization or improvement of hearing in 87% in this group of patients with pretreatment intractable progressive hearing loss. However, the study endpoint of improvement in 70% of patients was not attained. This short-term effect of possible stabilization requires further study. PET scanning was not useful as a tool to evaluate hearing loss in a limited subset of patients.