Stephen

We interviewed Dr. Stephen Krieger to discuss his research in the implementation of the topographical model of Multiple Sclerosis.

What is the concept behind the topographical model of multiple sclerosis (MS)?

DR. KRIEGER: MS is an incredibly heterogeneous, and in many ways, unpredictable disease. Some people with MS will have a relapsing course, others will take a progressive course of disease, and many will have a disease course that spans both a relapsing phase and a progressive phase.

We have traditionally divided MS into phenotypes like relapsing-remitting MS (RRMS), secondary-progressive MS (SPMS), or primary-progressive MS (PPMS), and these phenotypes have been foundational in our field and used to define clinical trial cohorts and outcomes. They also have been used for the approval of our medicines. In practice, however, it sometimes can be difficult to know precisely what kind of MS, what phenotypes of MS, that an individual patient has.

The topographical model, which was proposed four years ago, tries to unify our concepts of MS in a way that spans across those phenotypes and animates the disease course in a more dynamic way to bridge from one phenotype to another.

As an individual patient, for example, develops clinically isolated syndrome (CIS) or first attack, and then RRMS, and then later SPMS, that gets depicted in a dynamic visualization through the topographical model. The model also makes use of the idea that where an MS lesion is in the central nervous system (CNS) defines the clinical symptoms that it causes.

This is something that we have long known, and the art of localization in neurology has existed for at least a couple hundred years. But we have not used that in the way we have depicted MS clinical course in recent decades. The topographical model tries to bring this idea of mapping an individual patient’s disease topography back into the clinical picture.

 In the topographical model, the lesions are shown as different topographical peaks, via the hills and valleys of areas of MS damage across different regions of the CNS [image]. They are compensated for by reserve, by the ability that the nervous system has to compensate and to keep a disease process from crossing the clinical threshold and causing symptoms.  What the topographical model displays is that  patients with MS lose reserve as time passes.

We know that there is brain atrophy, brain stem atrophy, spinal cord atrophy, and retinal nerve fiber layer thinning in this disease. The topographical model takes the concept that MS causes a loss of tissue across the CNS and applies it to where the lesions are in the CNS. The coming together of those two things brings about the clinical picture unmasking the deficit from those lesions over time. The short version is a depiction of disease course in MS. The way it looks has been likened to a leaking swimming pool, where there is a shallow end and a deep end, and as reserve drains over time more and more of that subclinical disease becomes unmasked.

In the Laitman article (2018), you applied the model to real patients. What were the main findings from that study?

DR. KRIEGER: Until now, the topographical model has been conceptual with a visual depiction, and I think it has been important as an educational tool and an aid to help shape our thinking about MS in a unified way.

The Laitman et al research, is the first time we have applied the concepts of the model to individual patients to confirm whether we could map individual patients’ MS histories in the topographical model and see if we could depict their clinical course this way. We found that we could.

One of the most important points that the topographical model makes is the idea that as progression occurs and reserve is lost, there is an unmasking of underlying disease. Meaning, all of the signs and symptoms that a patient has had during their relapse when they were accumulating lesions should be re-revealed or recapitulated when reserve is lost and progression occurs.

To confirm this, we mapped ten patients in the topographical model. We characterized their signs and symptoms of relapses during the relapsing phase and we found that the vast majority of these symptoms had redeclared themselves at the time that these patients developed SPMS. Furthermore,  those symptoms were continuing to worsen in their pattern; that is in the pattern of their disease topography as the years have continued to pass since they developed SPMS.

This was the first empirical study in real patients to show that the principles of the topographical model held true. This recapitulation hypothesis of symptoms in progressive disease was borne out, and that can help to lay the groundwork for future empirical studies to see how this model can be used as a predictive tool.

How does this new theory of MS disease progression better inform treatment decisions than the disease course theories that currently exist?

DR. KRIEGER: We have had the clinical phenotypes for 20 years and it has been very helpful to us in the development of treatments that we have shown are effective for RRMS and in more recent years for PPMS. What we don’t really have is a way of personalizing and predicting the individual person’s disease trajectory.

Although we have prognostic factors that we know are important, such as age and MRI disease burden, there is still great uncertainty of the clinical course in the individual patient. If the topographical model can be further empirically validated using real world data, that could help us to predict what is going to happen to an individual patient. That can help us to make better treatment decisions for them because it could inform our treatment decisions in a more personalized way.

Is there any other recent research that supports these concepts?

DR. KRIEGER: We talk a lot about the need for biomarkers in MS to help us predict disease course and the topographical model makes the case that lesion location is a crucial biomarker. That is, the patient that has lesions in the spinal cord and the brain stem is more likely to have progressive signs and symptoms referable to those lesions.

A separate piece of work recently done by Keegan and colleagues that was published in Multiple Sclerosis Journal, looked at their own cohort of patients that had at least one critically located lesion, typically in the high cervical spinal cord or the lower brain stem, as being the crucial driver of the development of motor dysfunction and progressive disability.

In an editorial I wrote with my colleague, Fred Lublin, called “Location, location, location,” we point out that this is in some ways the best data in support of the concept of the topographical model that I have seen. It outlines a framework or a methodology where the importance of lesion location in defining the clinical picture and the risk of progression for an individual patient can be studied.

We interviewed Dr. Stephen Krieger to discuss his research in the implementation of the topographical model of Multiple Sclerosis.

What is the concept behind the topographical model of multiple sclerosis (MS)?

DR. KRIEGER: MS is an incredibly heterogeneous, and in many ways, unpredictable disease. Some people with MS will have a relapsing course, others will take a progressive course of disease, and many will have a disease course that spans both a relapsing phase and a progressive phase.

We have traditionally divided MS into phenotypes like relapsing-remitting MS (RRMS), secondary-progressive MS (SPMS), or primary-progressive MS (PPMS), and these phenotypes have been foundational in our field and used to define clinical trial cohorts and outcomes. They also have been used for the approval of our medicines. In practice, however, it sometimes can be difficult to know precisely what kind of MS, what phenotypes of MS, that an individual patient has.

The topographical model, which was proposed four years ago, tries to unify our concepts of MS in a way that spans across those phenotypes and animates the disease course in a more dynamic way to bridge from one phenotype to another.

As an individual patient, for example, develops clinically isolated syndrome (CIS) or first attack, and then RRMS, and then later SPMS, that gets depicted in a dynamic visualization through the topographical model. The model also makes use of the idea that where an MS lesion is in the central nervous system (CNS) defines the clinical symptoms that it causes.

This is something that we have long known, and the art of localization in neurology has existed for at least a couple hundred years. But we have not used that in the way we have depicted MS clinical course in recent decades. The topographical model tries to bring this idea of mapping an individual patient’s disease topography back into the clinical picture.

 In the topographical model, the lesions are shown as different topographical peaks, via the hills and valleys of areas of MS damage across different regions of the CNS [image]. They are compensated for by reserve, by the ability that the nervous system has to compensate and to keep a disease process from crossing the clinical threshold and causing symptoms.  What the topographical model displays is that  patients with MS lose reserve as time passes.

We know that there is brain atrophy, brain stem atrophy, spinal cord atrophy, and retinal nerve fiber layer thinning in this disease. The topographical model takes the concept that MS causes a loss of tissue across the CNS and applies it to where the lesions are in the CNS. The coming together of those two things brings about the clinical picture unmasking the deficit from those lesions over time. The short version is a depiction of disease course in MS. The way it looks has been likened to a leaking swimming pool, where there is a shallow end and a deep end, and as reserve drains over time more and more of that subclinical disease becomes unmasked.

In the Laitman article (2018), you applied the model to real patients. What were the main findings from that study?

DR. KRIEGER: Until now, the topographical model has been conceptual with a visual depiction, and I think it has been important as an educational tool and an aid to help shape our thinking about MS in a unified way.

The Laitman et al research, is the first time we have applied the concepts of the model to individual patients to confirm whether we could map individual patients’ MS histories in the topographical model and see if we could depict their clinical course this way. We found that we could.

One of the most important points that the topographical model makes is the idea that as progression occurs and reserve is lost, there is an unmasking of underlying disease. Meaning, all of the signs and symptoms that a patient has had during their relapse when they were accumulating lesions should be re-revealed or recapitulated when reserve is lost and progression occurs.

To confirm this, we mapped ten patients in the topographical model. We characterized their signs and symptoms of relapses during the relapsing phase and we found that the vast majority of these symptoms had redeclared themselves at the time that these patients developed SPMS. Furthermore,  those symptoms were continuing to worsen in their pattern; that is in the pattern of their disease topography as the years have continued to pass since they developed SPMS.

This was the first empirical study in real patients to show that the principles of the topographical model held true. This recapitulation hypothesis of symptoms in progressive disease was borne out, and that can help to lay the groundwork for future empirical studies to see how this model can be used as a predictive tool.

How does this new theory of MS disease progression better inform treatment decisions than the disease course theories that currently exist?

DR. KRIEGER: We have had the clinical phenotypes for 20 years and it has been very helpful to us in the development of treatments that we have shown are effective for RRMS and in more recent years for PPMS. What we don’t really have is a way of personalizing and predicting the individual person’s disease trajectory.

Although we have prognostic factors that we know are important, such as age and MRI disease burden, there is still great uncertainty of the clinical course in the individual patient. If the topographical model can be further empirically validated using real world data, that could help us to predict what is going to happen to an individual patient. That can help us to make better treatment decisions for them because it could inform our treatment decisions in a more personalized way.

Is there any other recent research that supports these concepts?

DR. KRIEGER: We talk a lot about the need for biomarkers in MS to help us predict disease course and the topographical model makes the case that lesion location is a crucial biomarker. That is, the patient that has lesions in the spinal cord and the brain stem is more likely to have progressive signs and symptoms referable to those lesions.

A separate piece of work recently done by Keegan and colleagues that was published in Multiple Sclerosis Journal, looked at their own cohort of patients that had at least one critically located lesion, typically in the high cervical spinal cord or the lower brain stem, as being the crucial driver of the development of motor dysfunction and progressive disability.

In an editorial I wrote with my colleague, Fred Lublin, called “Location, location, location,” we point out that this is in some ways the best data in support of the concept of the topographical model that I have seen. It outlines a framework or a methodology where the importance of lesion location in defining the clinical picture and the risk of progression for an individual patient can be studied.

We interviewed Dr. Stephen Krieger to discuss his research in the implementation of the topographical model of Multiple Sclerosis.

What is the concept behind the topographical model of multiple sclerosis (MS)?

DR. KRIEGER: MS is an incredibly heterogeneous, and in many ways, unpredictable disease. Some people with MS will have a relapsing course, others will take a progressive course of disease, and many will have a disease course that spans both a relapsing phase and a progressive phase.

We have traditionally divided MS into phenotypes like relapsing-remitting MS (RRMS), secondary-progressive MS (SPMS), or primary-progressive MS (PPMS), and these phenotypes have been foundational in our field and used to define clinical trial cohorts and outcomes. They also have been used for the approval of our medicines. In practice, however, it sometimes can be difficult to know precisely what kind of MS, what phenotypes of MS, that an individual patient has.

The topographical model, which was proposed four years ago, tries to unify our concepts of MS in a way that spans across those phenotypes and animates the disease course in a more dynamic way to bridge from one phenotype to another.

As an individual patient, for example, develops clinically isolated syndrome (CIS) or first attack, and then RRMS, and then later SPMS, that gets depicted in a dynamic visualization through the topographical model. The model also makes use of the idea that where an MS lesion is in the central nervous system (CNS) defines the clinical symptoms that it causes.

This is something that we have long known, and the art of localization in neurology has existed for at least a couple hundred years. But we have not used that in the way we have depicted MS clinical course in recent decades. The topographical model tries to bring this idea of mapping an individual patient’s disease topography back into the clinical picture.

 In the topographical model, the lesions are shown as different topographical peaks, via the hills and valleys of areas of MS damage across different regions of the CNS [image]. They are compensated for by reserve, by the ability that the nervous system has to compensate and to keep a disease process from crossing the clinical threshold and causing symptoms.  What the topographical model displays is that  patients with MS lose reserve as time passes.

We know that there is brain atrophy, brain stem atrophy, spinal cord atrophy, and retinal nerve fiber layer thinning in this disease. The topographical model takes the concept that MS causes a loss of tissue across the CNS and applies it to where the lesions are in the CNS. The coming together of those two things brings about the clinical picture unmasking the deficit from those lesions over time. The short version is a depiction of disease course in MS. The way it looks has been likened to a leaking swimming pool, where there is a shallow end and a deep end, and as reserve drains over time more and more of that subclinical disease becomes unmasked.

In the Laitman article (2018), you applied the model to real patients. What were the main findings from that study?

DR. KRIEGER: Until now, the topographical model has been conceptual with a visual depiction, and I think it has been important as an educational tool and an aid to help shape our thinking about MS in a unified way.

The Laitman et al research, is the first time we have applied the concepts of the model to individual patients to confirm whether we could map individual patients’ MS histories in the topographical model and see if we could depict their clinical course this way. We found that we could.

One of the most important points that the topographical model makes is the idea that as progression occurs and reserve is lost, there is an unmasking of underlying disease. Meaning, all of the signs and symptoms that a patient has had during their relapse when they were accumulating lesions should be re-revealed or recapitulated when reserve is lost and progression occurs.

To confirm this, we mapped ten patients in the topographical model. We characterized their signs and symptoms of relapses during the relapsing phase and we found that the vast majority of these symptoms had redeclared themselves at the time that these patients developed SPMS. Furthermore,  those symptoms were continuing to worsen in their pattern; that is in the pattern of their disease topography as the years have continued to pass since they developed SPMS.

This was the first empirical study in real patients to show that the principles of the topographical model held true. This recapitulation hypothesis of symptoms in progressive disease was borne out, and that can help to lay the groundwork for future empirical studies to see how this model can be used as a predictive tool.

How does this new theory of MS disease progression better inform treatment decisions than the disease course theories that currently exist?

DR. KRIEGER: We have had the clinical phenotypes for 20 years and it has been very helpful to us in the development of treatments that we have shown are effective for RRMS and in more recent years for PPMS. What we don’t really have is a way of personalizing and predicting the individual person’s disease trajectory.

Although we have prognostic factors that we know are important, such as age and MRI disease burden, there is still great uncertainty of the clinical course in the individual patient. If the topographical model can be further empirically validated using real world data, that could help us to predict what is going to happen to an individual patient. That can help us to make better treatment decisions for them because it could inform our treatment decisions in a more personalized way.

Is there any other recent research that supports these concepts?

DR. KRIEGER: We talk a lot about the need for biomarkers in MS to help us predict disease course and the topographical model makes the case that lesion location is a crucial biomarker. That is, the patient that has lesions in the spinal cord and the brain stem is more likely to have progressive signs and symptoms referable to those lesions.

A separate piece of work recently done by Keegan and colleagues that was published in Multiple Sclerosis Journal, looked at their own cohort of patients that had at least one critically located lesion, typically in the high cervical spinal cord or the lower brain stem, as being the crucial driver of the development of motor dysfunction and progressive disability.

In an editorial I wrote with my colleague, Fred Lublin, called “Location, location, location,” we point out that this is in some ways the best data in support of the concept of the topographical model that I have seen. It outlines a framework or a methodology where the importance of lesion location in defining the clinical picture and the risk of progression for an individual patient can be studied.