I doubt if they would approve you while you are taking eculizumab, and if you really do have paroxysmal nocturnal hemoglobinuria you almost certainly OUGHT TO BE on eculizumab. Realistically, this probably ought to be treated with gene therapy, but that's probably at least a half decade away.
Seriously, get absolutely state of the art treatment for this. Only then worry about a career in aviation.
And if the FAA somehow did give you a SODA, it would probably require reports from your treating physicians every six months. At least until after successful gene therapy.