The future of MS course descriptors

People living with multiple sclerosis need language that reflects both the biology of the condition and the realities of daily life, delegates heard at MSIF’s Global MS Research Meeting in London and online on Tuesday 6 October 2026.

The session, led by Dr Tim Coetzee, from the National MS Society in the United States, explored ongoing work towards a more biologically informed description of MS disease course. Participants from MS organisations around the world then discussed what any future change could mean for people living with MS, their families, and the organisations that support them.

Current terms, including ‘relapsing-remitting MS’, ‘secondary progressive MS’ and ‘primary progressive MS’, were established in 1996. A 2018 review summarises the original categories and how they were later updated. These terms have provided a common language for clinicians and researchers. However, understanding of MS biology has advanced considerably since then, while disease-modifying treatments have changed the course of MS for many people.

The session considered whether the language used to describe MS should evolve to reflect this progress.

Why the discussion is taking place

In 1996, there were no clear biological markers that could define the different clinical courses of MS. The established descriptions were therefore based on clinical observation and professional consensus. The course descriptions were revisited in 2013, when the framework retained the main clinical categories and added ways to describe disease activity and progression over time.

Since then, research has improved understanding of the processes that contribute to MS, including inflammation, nerve fibre damage, loss of myelin, repair mechanisms, brain reserve and biological ageing. Researchers also increasingly understand how genetics, sex, infections, health behaviours, treatments and wider social factors can influence a person’s experience of MS.

At the same time, disease-modifying treatments can reduce relapses and alter the expected course of MS. This means the existing categories may not fully capture a person’s current disease activity, progression or underlying biology.

No new set of MS course descriptors has been introduced. The discussion is part of ongoing work to explore whether and how descriptors could better reflect what is known about MS biology. Researchers and people with MS will need to agree on which biological features are meaningful, how they can be measured reliably, and how they relate to a person’s symptoms and disease course. Any proposed framework will also need to be tested in different clinical and health-care settings, including places where specialist services, MRI scans, or biomarker testing are not readily available.

While that work continues, a transitional approach has been proposed. It would keep the familiar terms “relapsing” and “progressive” and could provide a bridge between current terminology and a future framework. The details have yet to be settled. Any transition would need clear explanations for people with MS and clinicians, and careful consideration of how changes might affect diagnosis, treatment decisions, research and access to care.

The words people use matter

Workshop participants said that people affected by MS often describe their condition through its impact on daily life, rather than clinical course descriptors alone.

They shared examples such as difficulty walking, foot drop, fatigue, brain fog, pain and changes in thinking. People may describe having good days and bad days, or explain how they are feeling at a particular moment. Several participants said that these everyday descriptions can be more meaningful than a clinical label.

Participants also raised concerns about language that can be confusing or stigmatising. Some noted that relapsing-remitting MS can be incorrectly understood as a milder form of MS. Others highlighted terms such as “aggressive MS”, “wavy MS” and “smouldering MS”, which may require careful explanation.

One group said that people do not necessarily want to be defined by a label or moved from one definition to another without a clear explanation of what it means for them.

Participants said any new framework should be clear to people with MS, useful in conversations with clinicians and respectful of different experiences. It should support communication between people living with MS and clinicians, while recognising that people’s experiences may differ across countries, languages and communities.

Science and lived experience must work together

Participants supported a framework informed by biological evidence, while stressing that biological measures alone cannot capture the full experience of living with MS. A future description should account for symptoms that may not show up on an MRI or other clinical tests, including fatigue, cognitive changes and pain. As one workshop participant put it, “The new descriptions must be built around what people actually experience, not just what is measurable on an MRI.”

A biologically informed framework that still ignores fatigue, cognitive fog, pain and invisible symptoms has not fully served the community it describes.

Workshop participant

Participants said lived experience and biological evidence should shape the language together. The classification should also be useful for people with limited access to neurologists, MRI scans, biomarker testing or treatment.

The session considered how course descriptors are used in conversations between people with MS and clinicians, treatment decisions, clinical trials, research, treatment guidelines, drug approvals and health technology assessments. Any new approach will need to work across these settings without making treatment or support harder to access.

Protecting access to treatment and care

Participants said a change in terminology must not disrupt treatment or support, particularly in places where specialist services and diagnostic tests are hard to access. One group’s message was simple: Make sure access to treatments and services is unchanged.

A participant from the Multiple Sclerosis Society of South Africa (MSSA) said:

People should not lose treatment or support because terminology changes, or because the tests needed for a new classification are unavailable.” Participants also warned that people may worry about what a new term means for their diagnosis unless the change is explained clearly.

Organisations working in settings with limited specialist care called for clear guidance for regulators, health ministries, healthcare providers and other decision-makers. Families, funders and MS organisations will also need information, while healthcare professionals are likely to be the first people many patients turn to with questions.

The support MS organisations need

Participants called for a coordinated communications toolkit that MS organisations could adapt for their own countries and communities. They said resources should use plain, accessible language, avoid unexplained acronyms and be available in multiple languages. As one workshop participant put it,

We need clear explanations in accessible language, reassurance about what the change means for their existing diagnosis, and protection of access to treatment and support.

The toolkit could explain what has changed and why, use practical illustrations or analogies, and clarify what the change does and does not mean for people’s diagnosis, treatment and care.

We need simple communications about what the change is, and why it matters.

Workshop participant

Participants also suggested that common language, aligned with existing patient-reported outcomes work where appropriate, could help provide consistency across countries. Training and guidance would help MS organisations, clinicians and decision-makers communicate clearly and respond to questions from people affected by MS.

The discussion highlighted the need for advocacy across multiple stakeholders. MS organisations could help maintain clear, consistent messages while engaging with health ministries, regulators, lawmakers, providers and researchers.

An ongoing international conversation

The work towards a more biologically informed description of MS disease course is part of an ongoing international conversation. A roadmap paper published in 2026 sets out the case for transition and the work still needed to develop new descriptors.

For now, the emphasis is on listening, learning and preparing. The Global MS Research Meeting gave MS organisations an opportunity to share how current terminology is used in their communities, identify likely questions and concerns, and consider the support people may need if the language changes in future.

The discussions showed that the words used to describe MS shape communication, access to care, research and people’s understanding of their own condition. Any future approach will need to be scientifically robust, meaningful in everyday life, and implemented in a way that protects equitable access to treatment and support.