John Corboy, MD: The Challenge of Doing Clinical Trials on Stopping DMTs in MS

John Corboy, MD, a professor of neurology and the co-director of the Rocky Mountain MS Program at the University of Colorado: The biggest challenge is that we have so little data about stopping therapy that there's a significant concern that there'll be an acceleration of disease activity if you do discontinue. And we know that if you are younger and you discontinue disease-modifying therapies, there are numerous studies - especially with natalizumab (Tysabri) and then some small cases of fingolimod (Gylenia) - which show there may even be rebound of disease activity. So that the fear is that if you discontinue disease-modifying therapies they'll either be just an acceleration of ongoing progression, if people have progression, or just a rebound of inflammatory disease activity that you've been suppressing with your medications. That's a great fear for patients, and I completely understand that fear - it makes sense.

When you actually talk to patients, they sort of fall into 3 camps. When we asked them about their interest in a study like this, 1 camp says something like, “yeah I'm very interested in this, but I'm scared to go off my drug. Can you put me in the in the group that actually stays on their drug?” and the answer is, of course, is no because it's randomized. And then the reverse of that is someone says, “I’m really interested in your study, I'm so tired of taking these shots or whatever medication, side effects, and costs or whatever, and can I go in the group that goes off medication?” and of course the answer is no we have to be randomized.

So finding the group of individuals that has an open mind, is not leaning 1 way or the other, and is willing to be randomized, is actually a little bit more complicated than you would think. And it's because people come to this kind of decision-making with typically years and years of using these therapies, and they've developed very specific, sometimes very concrete, views of what the role of that therapy has in controlling or not controlling their disease. So just like physicians have biases, patients have biases as well, and that does play a role and some patients simply say, “Hey, you know what, when you get the data let me know and I'll be happy to act on that,” and that's maybe the fourth type of person and arguably, maybe, the most common.