What Is the Difference Between Relapsing-Remitting and Progressive MS?

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About 85% of people with MS start off with what's called the relapsing remitting form, an episode, and this may last anywhere from a few days, a few weeks, maybe even a few months. There maybe complete recovery with or without treatment. Then a year goes by and another episode occurs, another relapse or an attack, and that lasts for a couple of weeks, a month, whatever then it goes away.

Eventually some of these episodes may leave in their wake, some disability that doesn't go away it may be only partial recovery, and after some years typically around 15 years or so of illness the disease tends to stop being associated with episodes, but more of a steady progression. Usually characterized by problems walking and progressive cognitive problems

, memory, focusing on tasks and so on.

I'm talking about the untreated patient now. So we don't really have enough data to talk about what treatment does to progressive disease ,because we don't really have treatment since very long. It's only since 93 that we've had a treatment that was approved by FDA. So we believe that we at least put off this progressive phase and hopefully stop it all together.

I just don't have the proof to say that we could stop it all together this tendency to morph into this progressive phase. Another segment, that never really has attacks, or very rarely does they have this progressive problem, typically a walking problem. Slowly evolving, typically starts a little later usually around the age 45 to 50, equally involves men and women, and for these patients we don't really get any kind of response with our therapies.

They have no effect. And their MRIs don't tend to show accumulation of new white spots. They have white spots but they just sort of don't do anything. But what we see in those individuals is more and more atrophy. So all the progressive forms of MS, there's secondary progressive and there's primary progressive so called, the main characteristic now becomes atrophy of the brain, shrinkage of the brain, shrinkage of the spinal cord.

And the therapies we have don't impact that, at that stage. They impact it early on. When we do a clinical trial with a drug, a new drug especially, not in the past so much, we have ways to measure atrophy, and some of the drugs have shown an effect early on at least to prevent or reduce atrophy of the nervous system.

So will we have a long term effect, clinical trials only last two to three years typically. So it's hard to really make an evaluation like that in such a short time frame. Progression occurs over the long term. So a trial should be ten years, but it's so impractical it couldn't be done.