The best documented effect of DMDs (this applies to all of them) is the reduction in the number of relapses you experience. This is based on the studies conducted by comparing those on the drug and those on placebo.
It's a pretty abstract thing to really get a feel for in the real world though, because you'll only ever know of the relapses you *did* have, not the ones you avoided having. But the stats are there (sometimes confirmed by more objective third parties such as the National Institutes of Health or various academic bodies). The stats are really what varies with the medications.
The "older" DMDs (the injectables) generally claim a 30% relapse reduction. The newer medications edge up to 50%. When you start to talk about things like "progression" is where things get a little more murky. Since progression can really only be measured over time, the data's a bit sparse. Unfortunately, it doesn't seem that DMDs currently function primarily in a way that effects overall progression. But again, this is still not really firmly established - or at the very least, you'll see conflicting information. Sometimes lesions spontaneously shrink once the inflammation has passed. And perhaps the drug played a role in the relapse being shorter or less severe.
But don't get too caught up in lesion load mapping directly to disability or symptoms. I still have plenty of evidence on my latest MRI of my past relapses, but I still have "No evidence of disease activity" currently. I'm as fit as someone with MS can be. Alternatively, someone may have comparatively minimal damage on an MRI and yet experience life-altering symptoms.
When I think about the medication I'm taking the only things I care about are: can I handle the side effects, am I comfortable with the safety record, am I able to take it faithfully as directed, and is my MS staying on the very periphery of my life. Unless my medical tests tell me and my doctors it's not doing it's job, I don't worry too much about the future unknowns and the mountain of hypotheticals that come with having an incurable, chronic disease.
Please remember also that 30% or 50% or whatever does *not* mean that *you* will experience that rate of relapse reduction. These numbers reference the scientifically measured effect of a drug administered to thousands of people over several years. The number of relapses this group had was a certain percentage less than those of a similar group not taking any DMD. Any individual may possibly never go through another relapse, or go through dozens, med of any sort or no med at all, or anything between. It's impossible to know, and it's especially impossible to show the relapses we haven't had. Can't prove a negative.
I think many MSers are mislead by the stats, and thus expect a certain outcome for themselves. Bu this doesn't mean I'm opposed to the DMDs--far from it. I believe we have to go with the best info we have, and that's scientific data. If a given drug is hard to tolerate or doesn't seem to be effective (ask your neuro what s/he feels would constitute effective for you), then luckily there now are many others to choose from. Not taking anything is giving MS free reign to do its worst.
Thank you for the replies! Very helpful indeed.
I love these two quotes from your posts:
"When I think about the medication I'm taking the only things I care about are: can I handle the side effects, am I comfortable with the safety record, am I able to take it faithfully as directed, and is my MS staying on the very periphery of my life." (immisceo) <-- I am ready for MS to stop having center stage. Probably not a reality quite yet, but the idea of it being in the periphery is a great one!
"Not taking anything is giving MS free reign to do its worst." (essdipity) <-- I will very likely be pinning this to my bathroom mirror so that I force myself to stick with the medication as prescribed.
Thank you, again. It is so easy to get myself tied into knots trying to understand the medications and to set my expectations for the range of possible outcomes. I think I need to do more research to try to understand exactly how interferons work to fight relapses.
"While their exact mechanism of action is unknown, in theory, the interferon drugs seal off the blood brain barrier and inhibit the T-lymphocytes (T cells) from being activated. This prevents the T cells from entering the central nervous system and destroying myelin, and ultimately the nerve axons."
Thank you!! Even in language I can understand. :)
Every case of MS is different as far as progression. Progression can happen with or with out symptoms. You feel better when you have less relapses. There are two mechanisms in MS inflammation and nerve damage. When inflammation dies down so can symptoms. If they do not go away that is nerve damage which is permanent. Most relapses are due to inflammation. Steroids can temporarily work on inflammation. DMDs work on slowing progression. Since DMDs have been around nerve damage is way down. Less people are ending up in wheelchairs. Old timers before DMDs think we are so lucky to have them.
I got MS 1965 before DMDs so all my current symptoms are permanent. I would be on a DMD but I am on chemo and they interfere.
I am an odd duck none of my MRIS are different. They are carbon copies with only three lesions.