Everything about this drug looks clean. Well tolerated, big net of diseases it could treat, solid clinical trial results, easy to consume (pill). From what I've read, the mechanism of Ebselen in SPI-1005 sounds like a glorified version of NAC for inducing Glutathione.
The points made here about COVID-19 are interesting. In theory, COVID-19 should help speed this along. I also find it interesting how little cochlear inflammation is discussed. There are so many discussions on hair cells and synapses, but cochlear inflammation could be very responsible for tinnitus and hyperacusis.
Inflammation is one potential cause. Anything that impairs normal auditory signal can cause tinnitus.
You may not have meant to imply (maybe it's just how I read that though) that inflammation is the sole cause for everyone but in case it is ambiguous, I don't want people to fall into the trap of thinking there will be one cure for all as treating the underlying cause depends on treating the underlying cause for each individual.
That's why Frequency Therapeutics is testing their drug for tinnitus, because in people with hair cell loss, that's the reason for the abnormal auditory signal.
Anyway, re: Ebselen. It's actually a really complex drug the more I read about it, deceptively so. It's definitely not a lot like NAC other than antioxidant properties. It inhibits certain target enzymes (through reversible redox reactions), is a voltage gated calcium channel blocker, too. I wrote this in another thread about that:
"It appears that Ebselen also has voltage dependent calcium channel blocking activity. This explains why it might be especially useful as another "bomb blast pill", which they are recruiting for now.
Apparently, with acute ototoxic or noise exposure the neuro excitability contributes to an influx of calcium ions into the OHC that is large enough to overwhelm the buffering. This can damage the mitochondria and, ultimately, the cell. So, the theory goes, if you can block the influx and attenuate it, you can prevent permanent damage.
This goes into more detail about calcium's role in acute hearing damage:
Tonotopy in calcium homeostasis and vulnerability of cochlear hair cells
Anyway, this does make me wonder about side effects in certain people. For example, Amlodipine blocks similar channels and lowers blood pressure. So if someone already had hypotension or were already on that drug (not sure how much cross reactivity there is) maybe there could be excessive hypotension, for instance or a bradycardia (which is uncommon with Amlodipine and reversible when stopped). The blood pressure / vasodilation effects also might help blood flow in the ear (which is is an additional reason it might help Meniere's)."
All that to say, it passed two phases of clinical trials so far without safety issues so that's certainly encouraging.