[intro music] Host – Dan Keller Hello, and welcome to Episode Eighty-four of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m Dan Keller. People with MS take disease modifying therapies, or DMTs, for years. But is it possible to stop the drugs at some point or at least take a drug holiday? I spoke last fall at the ECTRIMS meeting in Barcelona with Dr. Ilya Kister, an assistant professor in the MS Care Center at the New York University School of Medicine. He has looked at various studies and registries that shed light on the question, and he discusses the utility and limitations of using observational data from big data sets. Interviewer – Dan Keller People know a lot about starting DMTs, but not about stopping. And, I take it, there's not much been looked at yet in terms of could you stop and what happens. Interviewee – Ilya Kister Yes, that’s a question that patients often ask, and clinicians certainly wonder about. Is it safe to stop the drug? When is it safe to stop it? And all the literature that I’ve seen on stopping the DMTs has basically analyzed the reasons for stopping them. The reasons for non-adherence—why did patient not want to continue—but there is very little data on actually what happened in terms of disease course. It’s just an observational study, you know. Do those patients continue to have relapses? Do they have more relapses or less? The only exception is natalizumab, where we have, you know, more than a dozen—probably two dozen—articles looking at what happens when you stop the drug. But that’s a little kind of almost an exceptional circumstance. There is a question of disease rebound and such. With the other drugs, very little to no data. So, so one wonders whether it’s an okay thing to do. MSDF What are the pros versus cons of stopping? Dr. Kister I think you can make almost equally appealing arguments on both sides. The arguments to continue the drugs, the main ones, are that relapses are unpredictable, and even though they’re less common as people age, we do see patients in practice, even in their 60s, who have relapses. And there was a recent study that showed that about 30% of secondary progressive MS patients have relapses. So, presumably, the drugs which work to decrease the risk of relapse would be helpful to reduce the risk of relapse even in those circumstances as well. But that’s not entirely clear, because they were never shown to be beneficial, truly, in the secondary progressive patients or in the older patients, because older patients are, by and large, excluded from all the studies. So we really don’t have any high-level data on these subpopulations. So the reasons to continue would be to try to prevent relapses, even in older patients. And the reasons to stop would be that the relapses are kind of few and far between. It may be not worth the hassle, and maybe the disadvantages of continuing in DMT long-term outweigh the theoretical risk of decreasing relapse rates. So it’s in a clinical equipoise situation, as far as I am concerned. MSDF How have you looked at this issue? Dr. Kister This is just kind of our individual practice, and many people may agree or not agree with it. This is not really based on our studies, but generally speaking, patients after age 60 who haven’t had relapses or MRI activity for at least five years, I do have a discussion with them and kind of feel them out whether they’re interested in stopping or not. And the reactions vary widely. You know, some people are very attached to their drug. They feel like it’s helping them and protecting them and has done good for them, and they don’t even want to think about stopping. And some people are very tired from being treated for many years. They don’t necessarily see the advantages of it, and they’re very willing to consider stopping and take you up on the offer. They just need a bless