So rather than approve the existing drug that's off patent, they approved a knock-off that will undoubtedly cost 100x as much. How typical.
If the answer is "no, but the marginal differences between ordinary ketamine and the new drug are enough that you'd want to prescribe the new drug instead"--well, that's new value added, isn't it?
The IV protocols for non-life-threatening cases usually involve a number of treatments over a short period (say 6 over 2 weeks), then increased spacing until a satisfactory equilibrium between avoiding symptom recurrence and not spending too often strapped to an IV is achieved.
I believe the nasal spray treatments are more frequent and less potent, but I've no firsthand experience with those, just the knowledge that one of the major limiters on getting a ketamine derivative into people's hands outside of an IV bag is the variability of dosage through e.g. nasal spray. (You can get a prescription for ketamine in a nasal spray from compounding pharmacies right now, but you will likely have decent variability of dosage each time.)
FDA will approve drugs from companies or individuals that pay for the application. The cost is pretty high today, something on the order of $2-3M USD just for the application. That's not including the cost of supporting data you need to have (Phase 1-3) that will likely cost a large amount to support (multiple centers, paying participants, wholesale cost of drug, paying investigators, researchers, statisticians, etc). Side note, should companies be able to justify exorbitant prices for their drugs based on this cost? No, probably not, but smarter people than myself have debated this on HN.
Why do I mention this? Because ketamine for use in intranasal form for treatment of depression is not off patent. That's right, Mount Sinai Hospital (Icahn School of Medicine) was granted that patent in 2007. A non-profit institution, mind you. So, if I were a drug company, looking to make a profitable form of intranasal ketamine, wouldn't I try and sidestep the patent entirely, reducing overhead on my end?
Also, calling esketamine a knock off is disingenuous. It's an enantiomer, therefore literally half of what is in normal ketamine. It's also probably the more potent half.
Edit: originally wrote that ketamine patent was granted in 2017, meant 2007. Edit2: originally wrote that NYU held the patent to intranasal ketamine when it was actually Mount sinai hospital.
The risk of abuse and addiction from using ketamine in a surgical setting is incredibly low. That's not necessarily the case (in fact, it definitely isn't) for nasal spray given as a treatment for depression.
Same drug, but completely different use case. It's very well known that it's a physically safe drug, but there is a definite risk of abuse and addiction, as evidenced by the number of people I know with ketamine abuse problems. It's not a drug that should just be given out willy nilly to everyone with depression, in fact a lot of people I know who have problems with ketamine abuse are clinically depressed or have other mental health issues.