There is already a (much!) cheaper alternative available, called AdrenaClick — bizarrely, though, unlike regular medication, pharmacists are not allowed to substitute the generic: if the prescription says “Epipen”, you have to get the full price branded one at four times the price. (Normally, as I understand if, if the prescription says a brand name, the pharmacist knows to offer a generic substitute if there is one — but for some reason, the Epipen managed to get itself excluded.)
The example letter does contain measures that would help — allowing importation from countries like Canada and the UK wouldn’t weaken product safety, but could act as a vital check on extreme pricing — and the FDA have serious questions to answer regarding the EpiPen and their obstruction of many generic rivals over the years. Apart from anything else, any patent covering the Epipen should have expired years ago, leaving it free to be copied — but for FDA intervention to protect the monopoly. Time to ask the FDA why they’ve done so?