MS traditionally has been separated into different types based on the course the disease takes with a relapsing-remitting course being the most common type. Secondary progressive MS can follow-on from this phase with a gradual accumulation of disability over time. Around 10% are diagnosed with a progressive course right from the onset, known as primary progressive MS. However, often there is no clear demarcation of the different disease stages.
It is thought that inflammation drives the relapsing stage of the disease whereas neurodegenerative processes drive the progressive forms of the disease, and this underpins the reasoning as to why the immune-modulating relapsing-remitting MS treatments have had limited effects on progressive MS.
However, results just published from a trial of relapsing MS medication, natalizumab (Tysabri) in secondary progressive MS, suggest that suppressing inflammation in the central nervous system can still help slow disability accumulation even after significant function has been lost.
The results of the phase three clinical trial with an extended follow-up has been published in the prestigious journal Lancet Neurology.
The trial enrolled 889 people with secondary progressive MS (SPMS) were randomly allocated into two groups, the first group received natalizumab for two years and the second group received a sham treatment. Participants were assessed every 12 weeks using the EDSS score (Expanded Disability Status Scale – a scoring system used to quantify disability in MS), the time it took to walk 25 metres, and what is called the nine-hole peg test which tests people’s upper limb function (arm and hand function) by timing them placing pegs into holes on a board.
Following the initial period of the trial the participants were given the opportunity to continue in the extension phase of the trial with everyone receiving natalizumab in this phase. 556 people continued in the study and were followed for an additional three years.
At the end of the first part of the trial, there was no significant difference in the number of people who had experience progression as measured by the EDSS score and the timed 25 metre walk. The scientists did, however, report a statistically significant difference in the nine-hole peg test, with natalizumab-treated people doing better, suggesting that this medication was delaying disabilities in the arms and hands.