How is Autoimmune Inner Ear Disease Treated ?
Classic treatments with steroids and immunosuppressants
There are several protocols for treatment. In cases with a classic rapidly progressive bilateral hearing impairment, a trial of steroids (prednisone or dexamethasone) for 4 weeks may be tried. In persons with response to steroids, in most cases a chemotherapy type of medication such as Cytoxan will be used over the long term (Sismanis et al , 1994; Sismanis et al, 1997), as long term high-dose steroids can result in severe side effects. In the author's practice, persons who respond to steroids are considered for treatment with Enbrel (see below), but this is presently not commonly used.
Plasmapheresis may be beneficial (Luetje and Berliner, 1997; Hussain et al, 2005). Plasmapheresis requires periodic visits using a machine similar to a dialysis unit.
Methotrexate, a chemotherapy and arthritis drug, has been shown to be ineffective in a large multicenter study (Harris et al, 2003).
Anti-TNF drugs and etanercept
Etanercept (Enbrel) is emerging as a promising agent for treatment of AIED (Rahmen et al, 2001; Wang et al, 2003). Enbrel is an anti-TNF (tumor necrosis factor) drug. TNF is an inflammatory cytokine (see above). Wang et al recently reported that etanercept given acutely in sterile experimental labyrinthitis resulted in much better hearing results in an animal model. On the other hand, Cohen et al recently reported that Enbrel was no better than placebo in persons with chronic AIED. In our clinical practice, we have had generally very good results in our patients with steroid responsive, progressing AIED and we feel that because of the study design (chronic hearing loss, no requirement for steroid response), that Enbrel is still worth trying.
Enbrel is given as an subcutaneous injection twice/week. Enbrel has generally been well tolerated but according to the manufacturer's information, people on Enbrel have developed serious infections (2%), nervous system disorders, and depression/personality disorders (1%).
A related agent, (infliximab) Remicade, was not found useful for AIED, but this study was based on only a handful of cases (Pyykko et al, 2002). Remicade is also not suitable for home use. There are newer agents that are in the drug pipeline that will need to be tested for their efficacy. Of the newer anti-TNF drugs, the most interesting is Humira, which is another anti-TNF drug, which was recently approved by the FDA (12/2002). It is not known so far whether this drug is useful in AIED.
Drugs already available in the world that are also anti-TNF agents include thalidomide, pentoxifylline (a vasodilator used for poor circulation), and rolipram (an antidepressant available in Japan and Europe). These drugs have not been tried in AIED.
None of these drugs has an official FDA indication for AIED. There recently has been some concern about these drugs affecting other health problems such as how well the body fights infection or kills tumor cells. In controlled studies of all TNF-alpha blocking drugs, more cases of lymphoma have been noted in treated patients than controls. Lymphomas are also often seen with use of other immunosuppresants. It is also generally felt that when these drugs are in use there should be increased vigilance for reactivation of tuberculosis.
In animals, attempts have been made to treat variants of AIED with oral collagen (Kim et al, 2001). Relapsing polychondritis is a disorder in which there may be antibodies to collagen and acquired deafness.