What we're doing about progressive MS
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What is progressive MS?
Most people with MS are initially diagnosed with relapsing MS, which means that they experience symptoms for a period of time (relapses), followed by periods of remission, when there are no symptoms.
But with progressive MS, there are no periods of remission and the condition gradually gets worse over time. However, the speed at which this happens varies a lot and it’s not yet possible to predict exactly how it will affect one person.
There are two types of progressive MS:
Primary progressive MS affects around 10 to 15% of people with MS. In this type of MS, clear periods when your disability stops or gets a bit better are extremely rare. Instead, your condition begins with mild symptoms that slowly get worse.
Secondary progressive MS follows relapsing MS. You no longer have clear periods when your disability stops or gets better (remissions) and your disability gets steadily worse.In the past, it usually took around 20 years for relapsing MS to change into secondary progressive MS. But thanks to disease modifying therapies (DMTs) this is changing:
- fewer people are likely to go on to secondary progressive MS
- for those that do, this could take longer to happen.
What causes MS progression?
In relapsing MS, immune cells attack the protective myelin coating around the nerves in the central nervous system. These attacks cause the messages that travel along nerve fibres to slow down, become distorted, or not get through at all. As these messages control everything the body does, any disruption will lead to the different symptoms of MS.
Fortunately, our brains have a system for repairing myelin damage. In relapsing MS, once the immune attacks die down, the myelin can start to be repaired. This allows the messages to get through once more, and the symptoms of MS subside.
In progressive MS, this system stops working as well.
We used to think that, in between relapses, nerve cells fully recovered and there was no lasting damage. We now know that with each relapse, residual damage builds up in the brain and spinal cord.
We think it’s a combination of many factors that causes this increasing nerve damage:
- continued myelin attacks
- myelin-making cells no longer responding to damage
- the build-up of harmful debris
- an increase in inflammation
Over time, this environment causes nerve fibres to die, in a process called neurodegeneration. With the nerve fibres lost, the messages can no longer get though, and can lead to any disability becoming permanent. This gradual, steady accumulation of disability is what we call MS progression.
In primary progressive MS, immune attacks aren’t as common as they are in relapsing MS. Instead, it’s thought the build-up of disability is caused by damage directly to the nerves themselves.
We’re learning more and more about how damage is caused in progressive MS. And we can use this knowledge to design new treatments.
Scientists are working on three key areas of research that together they believe can stop MS:
- stopping the immune damage
- promoting myelin repair
- protecting nerves from damage.
1. Stopping immune damage
For early progressive MS, we’ve started to see success with drugs that target the immune system.
DMTs can modify the behaviour of immune cells to prevent them from attacking myelin. These are mainly effective for relapsing MS, where immune attacks are more common.
But recent clinical trials have found that in early progressive MS, where immune attacks are still causing damage, “immunomodulatory” drugs may be able to slow MS progression.
Ocrelizumab is a DMT that targets B cells, stopping them from attacking myelin.
Ocrelizumab is now licensed to treat early primary progressive MS, though it is not available on the NHS. We’re campaigning to change this:
Another drug called siponimod traps immune cells in the lymph nodes, preventing them from crossing into the brain and attacking myelin. A phase 3 clinical trial, published in March 2018, found that in people with secondary progressive MS, siponimod reduced the risk of disability progression by 21% compared with a placebo. Novartis, the company who make the drug, have applied to the EMA to license siponimod for the treatment of secondary progressive MS.
However, for more advanced progressive MS, we don’t expect most immunomodulatory drugs to be effective. This is because the treatments stop immune attacks, and so can only help people experiencing active inflammation. DMTs can’t repair myelin damage or protect nerves. This means they can’t reverse symptoms that are due to progressive nerve loss.
2. Myelin repair
Scientists around the world are developing potential myelin repair therapies, which could enhance recovery from relapses and protect nerve fibres from damage.
In progressive MS, the cells in the brain that can repair and replace damaged myelin stop working as well as they used to. This leads to a build-up of damage in the nerves, which eventually may die.
Finding ways to kick-start the natural process of myelin repair is an important focus of our biomedical research programme. Our researchers are working to understand myelin repair in more detail, why it fails in progressive MS, and to identify targets for drug development.
Every discovery brings new opportunities for us to develop myelin repair treatments. And these could be effective for everyone with MS.
3. Protecting nerves from damage
The progression of disability in MS is not all down to myelin damage. We now know that the nerves themselves stop working properly. If we’re going to stop MS progression, we need to protect the nerves and make them as strong as possible.
Our researchers are looking at a number of different processes in the nerve cells to find out what goes wrong and ways to fix it. If we can find drugs that can protect nerves from damage then we have a real opportunity to stop MS getting worse, and even reverse disability for some people.
What we're doing about progressive MS
Our top priority, as agreed by people affected by MS and health care professionals, is to find effective treatments to slow, stop or reverse the accumulation of disability associated with MS.
We’re supporting research projects across the UK that are tackling all aspects of progressive MS, from myelin repair to finding effective symptom management programmes.
An international effort
We're a member of the Progressive MS Alliance. It’s a network of MS organisations from around the world who have come together to speed up the development of treatments for progressive MS.
By working together, we can achieve more.
Speak up for ocrelizumab for progressive MS
Ocrelizumab is the first licensed treatment for people with primary progressive MS. We're campaigning for it to be available to them on the NHS.