Here is a pdf file that gives you a lot of good information re getting your drug approved.
There are specific guidelines for the approach based upon the reason for denial.
http://www.medicarerights.org/partd_appeals_manual.pdf
(Drug plans in general tend to follow medicare rules and regulations.)
Our drug plan comes under Tricare for Life. We jumped through one hoop after another, every time we’d get one done, oops you have another hoop. They even said they didn’t get the doctors paper work, called his nurse a liar. Made her hot under the collar. Took about a year.