The problem is that the drug is not proven to be effective in...

The problem is that the drug is not proven to be effective in improving symptoms in patients, which is what it has to do to be marketed as such as a medication. Neural anti-inflammation is the postulated mechanism of action of the drug, but actually how it might work in vivo is not properly understood. We don't even know if reducing inflammation in nerves is actually a good thing. Vitamin supplementation is a great example of where supposed mechanisms of action were either wrong, or had the opposite effect to that expected - vitamin E supplementation INCREASING lung cancer risk rather than reducing it, folic acid supplementation increasing colonic polyp growth rate (yet perhaps reducing the formation of new polyps). That's why clinical trials are so important. You can sell drugs on the basis of less evidence of efficacy, but these are as nutritional supplements which won't be subsidised by government health systems, and will be worth orders of magnitude less.