Neil/all,
It is true that Gilenya is probably prior authed on most plans because of the first dose monitoring requirement and per-dose cost. However, your doc can accompany the prior auth form with a letter citing FDA approved investigational use, the otherwise dire prognosis, your cardiovascular/ophthalmologic status, etc. It is not unknown for prior auth criteria to be modified with appropriate evidence. I would at least try before giving up, if you really want to do this. In fact, if Max's neuro is willing, the fact that he, i.e. the VA, is rx'ing for this indication can be cited as well.
If the prior auth is denied, you can try Novartis' own patient assistance program. That too requires a neuro to fill out a form (which you can download any time). The worst they can say is no. Gilenya is not currently recruiting for an official ALS trial, ALS doesn't feature a long lifespan, and there is precedent for manufacturers to provide some support at the Phase II milestone.
As Max mentioned, there are clear contraindications for this drug and they are important -- if you value your vision and ability to stay off the floor. It is not like some of the other potential "self-trials." _Don't_ try this at home without clinical support.