So the FDA has approved a pill for MS, Gilenya (nee fingolimod). Now all we need is some data that tells us which of the available disease-modifying drugs might work better. Until somebody starts to generate comparative data, choosing a DMD for MS will be like choosing which brand of cigarettes to smoke: "Yeah, I like that Avonex is cheaper, but it's really a woman's brand. Rebif seems to work OK, but only black people shoot Rebif. Me, I'm more of a rugged, outdoorsey Copaxone guy."
If you want to reduce the cost of providing care for chronic conditions like MS, you should probably start by figuring out whether some drugs work better than others. If it turns out that some work better than others, create an incentive for using the drugs that work best. If they're all equally effective, create an incentive for using the drugs that are cheaper.