Ebselen: A Ray of Hope for the World of Hearing Loss?
Phase 3 drug trial – a cause for optimism?
Every time that I read about a new drug going into clinical trials for the treatment of tinnitus or hearing loss, I tend to do a contained, internal Happy Dance.
Recently, I read that the FDA has allowed Sound Pharmaceuticals to proceed with a Phase 3 (human) trial for its new drug known as SPI-1005 – ebselen. It is being evaluated for the treatment of hearing loss and tinnitus due to Ménière’s Disease.
Ménière’s Disease is still a medical mystery in many ways. This inner-ear condition is difficult to diagnose as there are no fool-proof, definitive tests. It involves episodes of dizziness and vertigo, tinnitus, fluctuating hearing and hearing loss.
Damage to inner ear structures ─ such as the cochlear hearing cells ─ is thought to be caused by inflammation reactions and oxidative cell stress. The end result is hearing loss that is all too often accompanied by tinnitus.
What is ebselen and how does it work?
During normal cell metabolism, the breakdown of chemicals leads to the formation of oxidative byproducts, often called free radicals. If left unchecked, these can be highly toxic and lead to premature cell aging and death. Luckily, the formation of such “oxidants” is balanced by cell anti-oxidants, which inactivate or neutralize the harmful oxidants.
Ebselen is new chemical that boosts or mimics the activity of an antioxidant enzyme that is present in many tissues, including the ears. Its name is glutathione peroxidase. During tissue damage, the amount or activity of this enzyme is often reduced, which decreases the cells’ defenses against free radicals. In the ears this results in sensorineural hearing loss and tinnitus.
And so, if ebselen could maintain or restore anti-oxidant action in Ménière’s Disease, might it also be of help in other situations of oxidative hearing damage? We’ll see.
According to reports, “SPI-1005 is given orally and is being tested in several neurotologic indications including noise induced hearing loss and two types of ototoxicity (hearing loss, tinnitus, dizziness or vertigo): due to aminoglycoside antibiotics (such as tobramycin) and due to platinum-based chemotherapy.”
In the end, all drug trials take time and lots of patience from those who see rays of hope popping up over the horizon. Many questions must be answered. I wonder if ebselen might still help those with chronic (long-term) hearing loss and tinnitus, like myself?
As of this writing, recruitment for the Phase 3 Ménière’s Disease study has not yet begun. As a resident of the World of Hearing Loss, I know that my expectations must remain managed regarding treatments, technology and research of any kind. And so, while awaiting more news, I have to hold off on my Happy Dance, at least for now
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