[intro music]

 

Host – Dan Keller

Hello, and welcome to Episode Forty-nine of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features Dr. Hugh Rosen of the Scripps Research Institute. But first here are some new items in the MS Discovery Forum.

 

If you’re an MS researcher, you may want to keep an eye on our Bulletin Board section, where we post a variety of news items that may be of interest. One of the items we posted this week is directly related to Dr. Rosen’s work. It’s a notice that a phase 3 trial of a sphingosine 1-phosphate receptor modulator called RPC1063 has started recruiting twelve hundred patients with relapsing remitting MS in the US. RPC1063 had its origins in Dr. Rosen’s lab.

 

We also recently added a notice of another clinical trial to the Bulletin Board. That one’s a phase 2 trial of oral laquinimod in primary progressive MS. And a third new Bulletin Board announcement is a request for information from the Patient Centered Outcomes Research Institute to identify patient registries and research groups with established cohorts of patients for potential collaborative research opportunities on comparative effectiveness research in MS treatment.

 

To read any of these announcements, go to msdiscovery.org and click first on Professional Resources and then on Bulletin Board. And if you have an announcement you think may be of interest to MS researchers, please send it to editor@msdiscovery.org. We won’t post purely promotional press releases, but if we judge the notice to be of general interest, we’ll be happy to post it at no charge.

 

In other news, it was a relatively slow week in published MS research. According to our curated list of the latest scientific articles related to MS, only 22 such articles were published last week. Typically at least 40 MS-related peer-reviewed articles are published weekly, and we’ve seen some weeks with more than a hundred. To see the weekly lists going back to March 2012, go to msdiscovery.org and click on Papers.

 

Our Drug-Development Pipeline includes continually updated information on 44 investigational agents for MS. This past week we added 2 new trials and 7 other pieces of information. The drugs with important additions are dalfampridine, fingolimod, masitinib, and natalizumab. To find information on all 44 compounds, visit msdiscovery.org and click first on Research Resources and then on Drug-Development Pipeline

 

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Now to the interview. Dr. Hugh Rosen studies chemical and biological approaches to the molecular mechanisms regulating lymphocyte trafficking. I met with him in his office at the Scripps Research Institute in La Jolla, California.

 

Interviewer – Dan Keller

We're talking about mostly new compounds, S1P1 receptor compounds; the prototype now I suppose is fingolimod. What's in development and do they appear to offer advantages?

 

Interviewee – Hugh Rosen

So, firstly, let me disclose that I am a cofounder of a biotechnology company called Receptos that has licensed an S1PR1 agonist from the Scripps Research Institute, so I have and my institution have a significant interest in this particular field.

 

Sphingosine 1-phosphate receptors act in a number of ways to modulate immune tissue damages in both autoimmune diseases and in viral infections. They've proven to be particularly efficacious in multiple sclerosis. Gilenya, of course discovered by Yoshitomi in Japan and developed by Novartis, has proven to be a clinically useful compound in the treatment of relapsing-remitting multiple sclerosis. And it appears to do so, at least in part, by altering the ability of lymphocytes to recirculate, and thus lymphocytes to reach the target tissues where they, in fact, produce demyelinating damage to the white matter of the central nervous system, and then the signs and symptoms of multiple sclerosis. So clearly these are useful compounds.

 

Gilenya, of course, is not a selective small molecule, it is an agonist of four of the five high affinity receptors for sphingosine 1-phosphate – S1P1, 3, 4, and 5 – and some of the associated side effects may be attributable in part to activity of Gilenya on other receptors like the S1P3 receptor that are not required for modulation in the treatment of multiple sclerosis.

 

MSDF

I see that it's referred to as an immunomodulator, not necessarily referred to as a receptor agonist. Does it not have pure agonist effect? Does it have any effects either because of the other receptors or at that same S1P1 receptor?

 

Dr. Rosen

No. In fact, Gilenya when phosphorylated is a full agonist of the sphingosine 1-phosphate receptors, and the newer compounds that are much more selective are also agonists of the sphingosine 1-phosphate 1 receptor. And some of the effects on them for cyto-mediated by downmodulation of the receptor, but I don't use the term modulators or immunomodulators because of the activity on the sphingolipid receptors per se, I use the term immunomodulator because of some of the unique advantages that we've demonstrated in model systems and in man about altering the activity of the sphingosine 1 receptor, because one of the beauties of immunomodulation is to blunt the immune response that causes collateral damage to the tissues whilst leaving sufficient of the immune response intact to allow protection from opportunistic pathogens – bacteria, viruses, and yeasts.

 

So one of the most striking features that we found – and these have been in some experiments done as a collaboration between my laboratory and the laboratory of Professor Michael Oldstone here at Scripps – has been in the area of influenza; pandemic influenza causes significant collateral tissue damage by having an overactive immune response. What we show is that the sphingosine 1-phosphate 1 receptor blunts that immune response and blunts the amplification of cytokines and chemokines so that you protect from the collateral tissue damage, but you leave intact the ability to mount protective, sterilizing T cell and B cell immunity to the virus. So you can eradicate the virus, sterilize it, you can provide a long-term memory both on the T-lymphocyte side as well as on the antibody side; there's class switching, there's affinity maturation, there are good protective immunity that is produced, and all this while blunting the immune response.

 

This is the Holy Grail as we think about treating patients, because the window for patients with autoimmune diseases like multiple sclerosis is that window between effective blunting of the immune response and the prevention of deleterious opportunistic infections that can have life-threatening consequences. So one of the advantages that I suspect we will see over time is that the sphingosine 1-phosphate agonists will prove to be particularly well-tolerated and have a wide window between the ability to limit tissue damage and progression of RRMS, and the need to protect patients from intercurrent infections or subclinical infections that become expressed later.

 

MSDF

Do the other sphingosine 1-phosphate receptors interfere with lymphocyte trafficking also, or do they have other effects which nonselective ligands would then induce these adverse effects through them, or do they also have some effect in terms of trafficking?

 

Dr. Rosen

They don't have significant effects on lymphocyte trafficking the way that S1PR1 does, both from the chemical approaches and the genetic evidence. S1P1 is clearly a toggle switch for lymphocyte trafficking. S1P2 is involved in the maintenance of hearing and in the function of vascular smooth muscle, so it regulates blood pressure. S1P3 is involved in cardiac contractility and also in the control of coronary artery caliber and the control of the airways, so S1P3 agonism is not a useful thing, it's actually quite deleterious. S1P4 and 5 have really no rate-limiting functions, at least of which I am aware, so there may be some redundancy and may not play a critical role in the modulation of health and disease.

 

MSDF

Do you see compounds coming along which will be more selective and therefore not lead to the adverse effects so much? And if so, are these compounds chemically similar or do they have different structures to attach to the receptor, the S1P1?

 

Dr. Rosen

These are clearly different structures, they're structurally very distinct from Gilenya and from each other. Novartis have a backup called siponimod. Actelion had a compound but it's only being used in psoriasis called ponesimod. Receptos has a compound now known as ozanimod – formerly known as RPC1063 – that is in two phase 3 studies for relapsing-remitting multiple sclerosis, a two-year study called RADIANCE and a one-year study called SUNBEAM, both of which are enrolling twelve hundred patients each.

 

MSDF

And the RADIANCE trial results looked pretty good; I mean, you had 85, 90% effects at 12 to 24 weeks or even at a year in terms of relapse rate. Does this look like the next compound to emerge?

 

Dr. Rosen

I think it's likely that ozanimod will be the next compound to be submitted for the regulatory process here in the United States and probably in Europe as well. The pleasing thing about the phase 2 data for ozanimod was, in fact, both the strong efficacy signal and a very well-tolerated safety profile; in fact the adverse effect profile of ozanimod and placebo were, in fact, indistinguishable and overlapping in the phase 2 studies. In addition, this very well-tolerated, favorable safety profile has been replicated in a highly successful phase 2 study in ulcerative colitis called TOUCHSTONE that was released recently. So clearly this is a mechanism of immunomodulation that could well prove to be useful for relapsing-remitting multiple sclerosis, but also in a range of other autoimmune diseases where treatments are hard to come by.

 

MSDF

Even with Gilenya, I think there have been reports of a couple of cases of progressive multifocal leukoencephalopathy, so it gives a nice balance between immune surveillance and inhibiting T cell trafficking, but it seems like not a perfect balance. Does it look like that margin will be narrowed in the future with other compounds?

 

Dr. Rosen

It's possible that it will be. I think the critical point to bear in mind is that real-world experience in tens of thousands of patients with hundreds of thousands of patient-years is really ultimately what is required to define these very rare events that on occasions do occur, and preexisting treatments with other immune-modifying agents such as Tysabri, for instance, may predispose to issues being seen later with PML. And I think that we always have to say that long-term patient experience and physician comfort are ultimately the best guides to the risk-benefit ratio.

 

MSDF

I think you've identified something like four compounds in development, those are some that I had seen. Are there others, or these are really the ones to focus on at this point for people to keep an eye on?

 

Dr. Rosen

There may well be others that are further behind. There have been a number of others that have had safety signals, particularly liver enzyme elevations, and significant first-dose cardiac effects. Arena have a compound that has recently completed a phase 1 multiple-dosing study and will go on to phase 2. So, you know, there are additional compounds and there will be additional compounds. Ultimately, patients do best when the best compounds appear, and the only way one knows that is to test them in man over the long-haul and define that risk-benefits for patients. And, you know, these multiple efforts really reflect the fact that a field has advanced, and that advancing field really does improve through intelligent intervention our ability to offer patients a better set of choices and a better set of long-term outcomes, which is what we're all about.

 

MSDF

We're still focusing here on RRMS, none of this applies to the progressive phase. Is there anything coming along there?

 

Dr. Rosen

You know, there's been one trial in primary-progressive; this was the Gilenya trial which didn't meet its endpoints. It may be that the mechanisms in rapidly progressive MS are a little different and that we don't yet, I think, understand the pathogenesis of that rather different presentation. So I'm not aware of a good alternate approaches to that, but that doesn't mean that the understanding isn't there for that to happen over time, it simply means that I'm not yet aware of it.

 

MSDF

Finally, in secondary-progressive MS, we can understand what's going on, what led to it; if you limit relapses, that's good. But does it look like primary and secondary really may be overlapping but not the same disease?

 

Dr. Rosen

I think there may be balances of pathogenesis where you can intervene more easily in some than in others. Clearly the sphingosine 1-phosphate agonists work particularly well by inhibiting the movement of lymphocytes into the brain. The movement of lymphocytes from the perivascular cuff into the parenchyma, into the white matter, where the demyelination proceeds. However, in parallel in multiple sclerosis, there are also events where there is collateral damage to neurons; we see axonal severing, we see elements of neuronal loss. Certainly with the sphingosine 1-phosphate agonists, there is some evidence that there is a diminution of cortical thinning over time with treatment, and that may be a really good thing.

 

I think that the neurodegenerative components is one that is hard to get a handle on right now, and that I think that these differences will become more obvious with early treatments of the immunopathology of multiple sclerosis. And that may well separate the autoimmune inflammatory damage and its sequelae from neurodegenerative mechanisms that may be entrained, and I think we will learn a lot from looking at those subsets of patients over time, particularly as more, better, and earlier treatment modalities allow the avoidance of significant damage in most patients.

 

MSDF

Is there anything important we've missed or you'd like to add?

 

Dr. Rosen

You know, I think for all of us who try to work at this interface of therapeutics, we do so because disease is, in fact, personal. We all know patients, we've all seen the multigenerational impact and depredations of multiple sclerosis on friends and family. And I think this is the very strong underlying motivator that drives us as scientists and as physician scientists to really try and bear in mind that the basic mechanisms and the basic therapeutic approaches that we pursue ultimately need a safe and effective human face to change the lives of patients in a positive way.

 

MSDF

Very good. Thank you.

 

[transition music]

 

Thank you for listening to Episode Forty-nine of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

[intro music]

 

Host – Dan Keller 

Hello, and welcome to Episode Forty-eight of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features Dr. Bruce Cree on the EPIC, CLIMB, and SUMMIT clinical trials in MS. But first here are some new items in the MS Discovery Forum.

 

We're very happy to report that MSDF has received three generous grants that will allow us to continue our mission: to focus attention on what is known and not yet known about MS and related conditions in a way that builds bridges among different disciplines. Genzyme has given us two grants. One will allow us to continue producing this weekly podcast for another year, and the other will allow us to develop an additional 12 monthly data visualizations. And Biogen has given us a grant for general operating support. None of these grants will interfere with our editorial freedom, and you can continue to count on MSDF to be an independent source of unbiased MS news.

 

A conference in Cambridge, Massachusetts several weeks ago sponsored by Orion Bionetworks outlined the progress and challenges in turning computational modeling into actionable knowledge in MS and other brain disorders. Allison Provost, who is Orion’s scientific program manager, has written a blog post describing the parts of the conference of particular interest to MS researchers. You can find her post by going to msdiscovery.org and clicking first on News and Future Directions and then on Blogs.

 

According to our curated list of the latest scientific articles related to MS, 50 such articles were published last week. To see the list, go to msdiscovery.org and click on Papers. We selected three of those papers as Editors’ Picks. Two of them are comprehensive review articles: one on biomarkers in MS and the other on MS immunogenetics. The third is an evidence-based consensus guideline on the use of MRI in MS diagnosis.

 

Our Drug-Development Pipeline includes continually updated information on 44 investigational agents for MS. This past week we added 1 new trial, we updated information on 3 other trials, and we added 13 other pieces of information.  The drugs with important additions and changes are alemtuzumab, fingolimod, glatiramer acetate, interferon beta-1a, interferon beta-1b, natalizumab, and rituximab. To find information on all 44 compounds, visit msdiscovery.org and click first on Research Resources and then on Drug-Development Pipeline.

 

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Now to the interview. Dr. Bruce Cree is a neurologist at the University of California, San Francisco. MSDF Executive Editor, Bob Finn, caught up with Dr. Cree in his office at UCSF’s Mission Bay Campus shortly after a departmental seminar entitled “An EPIC CLIMB to the SUMMIT.” 

 

Interviewer – Bob Finn

Dr. Cree, welcome.

 

Interviewee – Bruce Cree

Thank you.

 

MSDF

Now EPIC, CLIMB, and SUMMIT are acronyms for three MS clinical studies. So first, what's EPIC, what's CLIMB, what's SUMMIT?

 

Dr. Cree

Great question. So the EPIC study is a long-term observational study now in its 11th year at UC San Francisco. It's a a cohort study of multiple sclerosis patients who have been followed annually for the last 11 years. And this cohort initially had about 517 participants, and now – in its 11th year – we have about 91% of those patients coming back for ongoing assessments. The assessments include annual MRI scans, as well as clinical assessments and the blood draws for biomarker studies.

 

The CLIMB study is a similar related study that was developed independently at the Brigham and Women’s Children's Hospital in Boston under the directorship there of Howard Weiner. And it is also a long-term followup study. And now, after about seven years, that study has some 217 patients who have been retained out of the original cohort. 

 

SUMMIT is the idea of bringing together long-term, well-curated observational cohorts from multiple sites. And the first iteration of SUMMIT will involve investigators from Basal, Amsterdam, UCSF, and Harvard who will merge together their long-term observational cohorts into a larger study. And the hope here is that we will obtain greater statistical power and be able to answer some of the more pressing questions about MS therapeutics, outcome measures, and utility of both conventional and nonconventional MRI in assisting with the diagnosis and management of patients.

 

MSDF

So in the EPIC study, I'm struck by the fact that you've been able to retain 91% of your patients after 11 years; whereas in the CLIMB study they've lost 90% of their patients in just 7 years. How do you account for that difference?

 

Dr. Cree

The EPIC study has had a great amount of support for long-term followup and subject retention. And we've gone to great lengths to keep our participants interested in the study and wanting to come back. And we have a terrific group of study coordinators who work day and night to maintain contact with our patients, inform them about why it's important for them to participate in the study. And we've even done outreach where we've gone to people's homes to perform evaluations in their homes where they were too ill to come in, as happens with multiple sclerosis as people develop more advanced disability. So we have very good retention as a consequence of the hard efforts made on behalf of the overall study by the coordinators and other members of the team. 

 

MSDF

Now you've used several measures of disease progression in the EPIC study, as have others in other studies. There's the EDSS, there's the MSFC, and there are several other measures. But let's talk about the EDSS first. That's probably the most commonly used measures, and it's also the one that people seem to love to hate. 

 

Dr. Cree

Yes.

 

MSDF

Can you tell me about the EDSS and what its advantages and disadvantages are?

 

Dr. Cree

Yeah, so the Expanded Disability Status Scale of Kurtzke is an ingenious scale that was really intended to describe where patients are at during the course of their lifespan. And it's a 10-point scale with half-point increment changes after the score of 1. And this scale has been adopted for use as the disability outcome measure in all MS clinical trials. The scale has a fair amount of inter-rater variability, which makes it challenging to administer. Because anytime you have a scale where there's a fair amount of variability it gets harder to interpret change. We did look at the EDSS systematically and looked at change over the first few years in the study and used that as a predictor for long-term disability transitions. We also looked at harder endpoints in the EDSS such as the time it takes for patients to go from no systems, disease onset, to the time where they require a cane to ambulate. 

 

You mentioned the MSFC, the Multiple Sclerosis Functional Composite. This is a set of scales that were developed for use in multiple sclerosis that included the Timed 25-Foot Walk, which is a measurement of how fast somebody can walk 25 feet. That is clinically relevant because the speed at which somebody walks correlates quite well with the distance they can walk. So the faster you can walk 25 feet the longer you can walk. The 9-Hole Peg Test is a test of upper arm coordination and function. And the Paced Auditory Serial Addition Test is a test of cognitive function that measures specifically the tension and processing speed. 

 

So we looked at these things, and we set up thresholds based on other clinical work that were considered to be clinically meaningful changes. So with respect to the Timed 25-Foot Walk and 9-Hole Peg Test, we were looking for a 20% worsening in function over the course of the trial. And with respect to the Paced Auditory Serial Addition Test – or PASAT – we were looking at the reliable change index for that outcome. And so these have been validated outcomes that are related to actual disability.

 

So we looked at all of these measures. And what we found was that when we looked at our relapsing MS patients about half of the patients experienced worsening in terms of EDSS change over 10 years. For the patients who had progressive multiple sclerosis, about 70% of them worsened. And then for these more stringent measures with respect to the MSFC components, we found lower proportions of patients with relapsing MS in secondary progressive or primary progressive disease had worsening in those outcomes, as well. So those were our endpoints for the study; they're clinical endpoints.

 

MSDF

One of the things I noticed in your talk was that there was a great deal of overlap between the EDSS and the overall MSFC score; whereas there wasn't much overlap between the individual components of the MSFC score. What is the significance of that?

 

Dr. Cree

Well the EDSS is itself a composite measure, and people tend to forget that. Especially earlier on in the scores that go from 0 to about 4, there you have 6 functional scale scores that contribute to the overall EDSS. That includes assessment of vision, brain stem function, motor function, sensory function, cerebellar function, bowel and bladder function, and cerebral function. And those separate functional scale scores are scored independently and then are summarized into an EDSS score between 0 and 4. After that, the EDSS score becomes really much more of an assessment of how far patients can walk until they have hit the major disability milestones of an EDSS of 6, which is walking with a cane, 6.5 a walker, 7 a wheelchair, or 8 bed bound. 

 

MSDF

So why is there a lot of overlap between EDSS and MSFC but not so much overlap between the components of MSFC?

 

Dr. Cree

So when you look at the MSFC, you have two measures to the MSFC that are looking at motor function: the 9-Hole Peg Test and the Timed 25-Foot Walk. They can also be measures of cerebellar function. Both of things are very well measured in the EDSS by the functional scale scores for pyramidal and cerebellar function. The PASAT is not as well measured in the EDSS, although we have a cerebral functional scale score it's not a very precise measure, and there's a weakness associated with EDSS. Whereas in the MSFC, it's a very precise measurement. 

 

When we look at the individual MSFC scores themselves, you can have patients who worsen in terms of walking, patients who worsen in terms of arm function, and patients who worsen in terms of cognitive function. And there is some degree of overlap in those three domains but not complete. And that just underscores how MS will affect different individuals differently. Some people have more ambulatory impairment, other people have more upper limb function impairment, and still other people have more cognitive impairment.

 

MSDF

You made an interesting analogy to rheumatology in the treatment MS: the question of whether you should treat to no evidence of disease activity. I wonder if you can talk about that analogy and the NEDA, or no evidence of disease activity, goal.

 

Dr. Cree

Sure. So in rheumatology in the 1990s, the discussion at that time had to do with how to treat rheumatoid arthritis. And this concept was advanced, which was a treat-to-target approach. The idea of using increasingly effective therapies to silence and suppress any evidence of active rheumatoid arthritis. And this strategy turned out to be extremely effective in treatment of rheumatoid arthritis. And instead of waiting for people to develop more disability, initiation of early highly effective treatments and really suppressing all joint inflammation became the current standard of therapy. And this has resulted in significant improvements in long-term disability in patients who are living with rheumatoid arthritis. 

 

So taking that example and extending it to the field of multiple sclerosis, the idea here is that you have evidence of active multiple sclerosis on MRI scans such as gad-enhancing lesions and new T2 lesions; and evidence of relapses, which are clinical manifestation of acute inflammation; and disability progression, which is looking at the EDSS score and saying okay well if we have a combined measure that looks all of these things, and we try to suppress disease activity perhaps we're going to wind up with better outcomes. And so, this metric of no evident disease activity is defined as no evidence of relapses, no evidence of disability progression by the EDSS, and no evidence of MRI disease activity. 

 

And it was originally developed in the context of clinical trials; specifically the pivotal trial of the natalizumab versus placebo study. And a certain proportion of patients in that study met this criteria of no evidence of disease activity. Subsequently, with more recent trials, other compounds have also been looked at and compared to their placebo or active comparator controls. And in each of these studies, you can see differences between treatments with respect to the proportion of patients with no evident disease activity. 

 

The field of MS today is considering use of no evident disease activity as a therapeutic strategy or goal so that one would escalate therapy to the point where you see no evident disease activity. And the hypothesis here is that if you are able to effectively reach no evident disease activity that that is similar to putting patients in remission or preventing further disability from occurring. So we were very interested to find out whether there was long-term prognostic value of this marker, no evident disease activity. 

 

And so, within the EPIC study, we looked at no evident disease activity over the first two years of the trial, and there was a proportion of our patients from this study who met those criteria: who had no change in terms of disability, no change in terms of clinical relapses, and no evidence of active multiple sclerosis by MRI scan. And we thought that that group would have a better outcome overall than the rest of the cohort. To our surprise, we found that there was no predictive value of no evident disease activity on any of the clinical markers that we looked at for 10 years. 

 

So these patients had exactly the same risk for disability progression as patients who had evidence of active multiple sclerosis. And this was very perplexing; we just didn't really understand why that would be the case until we really started to look at the impact of treatment and use of escalation therapy in our cohort. And I think that when you look at the influence of therapeutic intervention in multiple sclerosis the effect size of therapeutic intervention is so great that other markers of biological disease activity such as new lesions wind up being minimized by the therapeutic impact. And as a consequence, things that might have been predicted based on natural history studies – such as brain volume loss, new lesions – become less apparent as having clinical meaning over a 10-year period of time because of the dominant influence of therapeutic intervention. 

 

With respect to the no evidence disease activity, one of the questions that I think needs to be answered is do we really have the best markers for this? And if we are going to use a treat-to-target approach, are the things that are currently being looked at in no evident disease activity the right things to look at? And there is now interest in looking at other markers, as well, looking in incorporating, for example, brain volume into the no evident disease activity. And it will remain to be determined whether other ways of looking at no evident disease activity wind up performing better as a long-term predictor.

 

MSDF

So when you're confronted with an individual patient – a new patient early in their course of disease – every neurologist is confronted the question of whether you start them with an interferon and escalate as they progress, or whether you start them with a highly active therapy. How do you make that decision, and how does the evidence from EPIC inform that decision?

 

Dr. Cree

That's a great question, and I think this is probably one of the most provocative aspects of this long-term study. In EPIC, we used the escalation strategy where we began with so called platform therapies; drugs that are used as disease-modifying therapies that have been around for a long time, specifically the interferons and glatiramer acetate. And in the event that patients experienced relapses or had other markers of worsening such as brain volume loss, many of those patients were escalated onto what we would consider to be high-potency therapies. Drugs like natalizumab or medications that are off-label but still used in treatment of multiple sclerosis like rituximab or cyclophosphamide. 

 

So we used this escalation strategy in this cohort. And what we found was the following. Treatment escalation was not associated with improved outcomes. In fact, treatment escalation was associated with worse outcomes in some patients. Now, why would that be the case? Well there's probably a confounder there of the indication to treat so that the patients who were getting escalation therapy are doing worse, and so they get the escalation therapy. So what we don't know from this study is if those patient hadn't gotten escalation therapy how would they have fared? We can't answer that question. That would require a randomized controlled trial. 

 

But what this study does provide is this provocative idea that perhaps escalation therapy was really too little too late. That we were identifying a group of people who were at high risk of disability progression, but we weren't really setting things back to restore them onto a normal pathway and certainly not to prevent long-term disability. And this raises the idea that perhaps we should be utilizing these higher-potency therapies earlier. Now, that type of approach – the maximal efficacy approach – doesn't have data yet to support its use, but there are a few provocative studies that suggest that high-potency therapy might be associated with better outcomes. And we have the recent results of the cladribine study in clinically isolated syndrome where we had the best data yet for use of a broad-spectrum immune suppressant in terms of venting, time to the next clinical or radiographic event in patients who have presented with a first demyelinating event. And that study out performed all prior trials in clinically isolated syndrome so raises the question should be using an aggressive therapy right from the get-go?

 

And then, we have the alemtuzumab pivotal trial where alemtuzumab was compared head-to-head versus interferon beta-1a twice weekly in newly diagnosed patients. And in that study, alemtuzumab also out performed interferon beta-1a on many of the short-term markers of inflammatory disease activity. And we recently saw long-term data with alemtuzumab indicating that those patient do really quite well over a four-year period of time. So actually midterm data. 

 

So we have a few lines of evidence to suggest that perhaps we should be using these high-potency therapies earlier. What we don't know is the relative risk-to-benefit profile. Certainly these higher-potency therapies carry greater risk to the individual subjects who are treated with these medications. And what we ultimately have to determine is whether those risks at a population level are worth the potential benefits of using a greater potency therapy early on in the course of MS. 

 

It's my opinion that it's unlikely that the pharmaceutical industry is going to answer this question for us definitively. This type of approach to compare escalation therapy to high-potency therapy or maximal efficacy therapy from the get-go will require quite a bit of time of followup – at least five years if not longer – and will require large studies. So it seems to me unlikely to be endorsed by the pharmaceutical industry. It also seems unlikely that it's going to be sponsored by national organizations such as the National Institute for Neurological Disease and Stroke because of the extremely high costs associated with this type of clinical trial. 

 

So that raises the question how are we going to answer this pressing unmet and unanswered question? And I think observational studies such as EPIC will be able to do this when merged together with other long-term followup cohorts. Today we have treatments that we didn't have 10 years ago, for example, fingolimod, dimethyl fumarate, alemtuzumab. These medications are currently being used in clinical practice. And I think we should be responsible for aggregating data on the patient experience with these medications, putting it into a systematized process for analysis, and aggregating this type of data across multiple centers. And that really is the goal of SUMMIT, which is going to involve pooling together our patient experience with our existing cohort, as well as new cohorts from UCSF, from Harvard, from Basal, from Amsterdam, and hopefully from many other MS centers as well. And then, with that pooled data, we'll hopefully be able to answer this question in a meaningful way. 

 

MSDF

Well, Dr. Cree, thank you very much. 

 

Dr. Cree

My pleasure. 

 

[transition music]

 

MSDF

Thank you for listening to Episode Forty-eight of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations. 

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

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Host – Dan Keller

Hello, and welcome to Episode Forty-Seven of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features the second part of a two-part interview with Dr. Hans Lassmann, who discusses oxidative stress as a mechanism of tissue injury in progressive MS. But first, here are some of the new items in the MS Discovery Forum.

 

According to our curated list of the latest scientific articles related to MS, 56 such articles were published last week. To see the list, go to msdiscovery.org and click on Papers. We selected two of those papers as Editors’ Picks. One of them includes revised guidelines from the Association of British Neurologists on prescribing disease-modifying treatments for MS. The other describes an international consensus on diagnostic criteria for neuromyelitis optica and related disorders.

 

Our Drug-Development Pipeline includes continually updated information on 44 investigational agents for MS. During the month of June, we added 10 new trials, we updated information on 6 other trials, and we’ve added 67 other pieces of information. The drugs with important additions and changes are alemtuzumab, cladribine, cyclophosphamide, daclizumab, dalfampridine, dimethyl fumarate, fingolimod, glatiramer acetate, idebenone, interferon beta-1a, interferon beta-1b, laquinimod, rituximab, natalizumab, and ocrelizumab. To find information on all 44 compounds, visit msdiscovery.org and click first on Research Resources and then on Drug-Development Pipeline.

 

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Now to our interview with Dr. Hans Lassmann of the Medical University of Vienna in Austria. Last week we spoke about biomarkers, and this week we’ll discuss oxidative stress as a mechanism of tissue injury in progressive MS.

 

Interviewer – Dan Keller

What's interesting there at this point?

 

Interviewee – Hans Lassmann

The big problem in multiple sclerosis is that we have very good therapies for the early stage of multiple sclerosis, and they all interfere with the inflammation and the immune system. But when the patients have reached a progressive stage of the disease, then all these therapies are currently noneffective. So the key points were to define what are actually the mechanisms of inflammation and tissue injury in the progressive stage of multiple sclerosis, and there are still a lot of open questions. It is clear that even in the progressive stage there is an inflammatory process, and this inflammatory process is associated with active tissue damage. From that certainly we cannot definitely conclude that the inflammatory process drives the tissue damage; however, it's clearly associated.

 

Now, we were then very interested to see what are the mechanisms of tissue injury. And this involves, first of all, studies on the nature of the inflammatory process. And here what we found is that in the progressive stage of multiple sclerosis the inflammatory reaction is predominantly hidden within the central nervous system behind a repaired blood-brain barrier. So that means this inflammatory process is no longer really under control of the peripheral immune system. And also, the therapies which we have currently mainly interfere with immune functions in the periphery, and they have actually very little access to an inflammatory process which is taking place within the central nervous system.

 

So that means that new drugs have to be developed and tested which actually exert an antiinflammatory or some neuroprotective action directly within the central nervous system. And there are now a number of the large companies fully engaged in this process, and there are new candidates coming up, which will have to be tested in proper clinical trials in patients with progressive MS.

 

The second question, which we have mainly addressed during the last year, was the mechanisms how the tissue damage is induced. And in this regard, we concentrated on cortical lesions in multiple sclerosis, which are very, very specific for the disease. And we compared in gene expression studies these cortical lesions not only with normal controls but also with inflammatory controls. And we used here a disease which has very similar inflammatory infiltrates, as you see in multiple sclerosis brain, but doesn't lead to the MS typical demyelination, and this is tuberculous meningitis. And then we also used as a control for neurodegeneration Alzheimer's disease just to see what is a reaction in gene expression due to degeneration of neurons.

 

And when we did that, actually it was interesting to see that there were relatively few genes which were specifically changed in their expression in multiple sclerosis patients in comparison to these other disease controls. And these genes were, in part, associated with inflammatory processes. A large part of the genes were associated with a more or less single pathway of tissue injury, which includes oxidative injury leading to mitochondrial injury and its secondary consequences. And then, there were also some genes involved which were MS specifically related to tissue regenerative processes.

 

We have then looked in further detail, and it now turns out that this cascade of oxidative injury leading to mitochondrial dysfunction and with that to a state of energy deficiency is actually one of the major driving forces of neurodegeneration in the progressive stage of multiple sclerosis. So this oxidative injury is, in part, driven by the inflammatory process. But it is also augmented by factors which are related to age of the patients and to the accumulation of lesion burden due to the chronic disease.

 

So here the central portion is the activation of microglial cells which can, on the one hand, be activated in the inflammatory process, but they also get activated when tissue is damaged due to completely different causes. And they also get activated just simply in an aging process. And in this respect, then they get activated in a pro-oxidative form. And then, the tissue injury can further be propagated through additional age-related changes, including, for instance, the accumulation of iron in the central nervous system and also obviously the chronic microglia activation due to retrograded and anterograde degeneration when lesions already present within the central nervous system.

 

MSDF

Are the microglia just overdoing what they normally would be expected to do? I mean macrophages use oxidative systems to get rid of pathogens.

 

Dr. Lassmann

Yeah, this is absolutely true. That is a key element of microphage and microglia function. And this is exaggerated in both the aging process, as well as in the chronic inflammatory state like multiple sclerosis. The question only remains what is really driving this massive microglia activation in MS, which is even more and more pronounced than even in very severe other inflammatory diseases of the central nervous system.

 

MSDF

Can you identify or has anyone identified factors that disappear with aging or are increased with aging that may lead to this state?

 

Dr. Lassmann

That is also not really very clear now. I think one interesting aspect is that this massive microglia activation in the direction of oxidative stress you don't really see in rodents and even not in primate experimental models; you see it in humans. And the reason for that is not completely clear, but it may very well be that environmental factors actually play a major role. I think one of the major differences between humans and these experimental animals is that the experimental animals are genetically very homogenous; they are generally inbred strains. And the second is that they are kept under a very constant pathogen-free environment. And this is very different in a human situation, and these animals also have a very … standardized diet. Now this is completely different in human situations, and there are certainly many factors, including peripheral infections but also including diet changes, and many other factors can actually have an influence on microglia in the central nervous system.

 

MSDF

And experimental animals also have optimized diets; people have figured out the nutrients they need I suppose. They're getting a good diet compared to people who knows how everybody is eating these days.

 

Dr. Lassmann

Yes, that's absolutely the case. They have a standardized diet, and they certainly are not exposed to very much of the fats, for instance, which we take into when we eat fat pork meat.

 

MSDF

Do any of the antiinflammatory agents modify the course? Things like lipoxygenase inhibitors and things like that? Not necessarily NSAIDs but now that you bring up fats?

 

Dr. Lassmann

I think there is certainly an aspect behind that is that lifestyle control certainly has a beneficial effect. One can just see that in a way that environmental lifestyle factors, which actually also increase the risk for vascular injury or other things, will be certainly deleterious in a patient with progressive multiple sclerosis where the brain is already damaged due to the original disease process and where the functional reserve capacity of the brain is already partially exhausted. So in that case, even minor changes – which are related to lifestyle or aging – will have a more dramatic effect in such a brain than in a normal aging brain.

 

MSDF

Finally, circling back to something you said at the beginning, in progressive MS I think you said that the immune system the cells have now entered the brain, but the blood-brain barrier has – once again – become a real barrier. So do you really have an immune response running autonomously in the brain no longer subject to any sort of peripheral control?

 

Dr. Lassmann

Yeah, this is certainly a very important open question. We know that the inflammatory cells are present within the central nervous system in the progressive stage and that they are associated with the degenerative processes and the demyelination. We know currently very little about the exact phenotype and functional activation of the inflammatory cells within the central nervous system. This is actually a large research project, which is running currently in my lab, to try to define exactly the functional polarization of the cells within the MS lesions and to determine their activation state, their proliferation rate, and so on.

 

What we can say from our preliminary data on that is that they are present, they are in part activated. They also express certain transcription factors, which would be associated with a proinflammatory state in the central nervous system. However, overall all these changes are relatively small in comparison to an acute, for instance, virus-induced inflammatory process in the brain. So it seems to be that there is a slow and low-grade activation state which, however, could be completely sufficient to drive the degenerative process in the patients. But that is not the final answer yet.

 

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MSDF

Thank you for listening to Episode Forty-seven of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

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