It depends on the drug and it's usage, but "because of their size and comparatively long duration, Phase III trials are the most expensive, time-consuming and difficult trials to design and run" [1].
It's possible to get the nasal spray prescribed and filled by a compounding pharmacy. Those doctors will want you to spend $3,000 for the initial infusions. It won't matter to them that you had the initial infusions elsewhere. They want the full treatment experience as well.
It's possible that the J&J spray will be approved in 2018.
In some countries in Europe it's already possible for a psychiatrist to request (legally) such preparation from a pharmacy and they will prepare it.
Legend has it some first responders are carrying ketamine nasal sprays as a first help for depressed people wanting to commit suicide. I wonder if it's true.
Can anyone comment on how long it might take for it to hit the market, from this stage?