Switching from Tysabri (natalizumab) to moderate-efficacy disease-modifying therapies (DMTs) puts patients with multiple sclerosis (MS) at a higher risk of further disease activity and disability progression compared with those who switch to a high-efficacy DMT, a new study has found.
Tysabri is often used to treat people with relapsing remitting MS and is thought to prevent immune cells from entering the brain and attacking neurons. It is high-efficacy and has been shown in clinical trials to reduce both relapses and the number of new or enlarging lesions.
The problem with Tysabri, and the reason most people are taken off it, is long-term use is associated with complications such as a very serious brain infection called progressive multifocal leukoencephalopathy (PML).
In this real-world study, all patients switched from Tysabri to either a moderate-efficacy DMT, either Tecfidera or Gilenya, or a high efficacy therapy, either Lemtrada, Ocrevus or rituximab. More than half of the patients had been taken off Tysabri because they were considered to be at risk of PML.
The amount of patients who had experienced relapses after six months of switching medication was similar in those who had switched to a moderate-efficacy DMT (11.7%) and a high-efficacy DMT (8.7%).
MRI scans showed a greater difference between the two, however, as those on moderate-efficacy DMTs were at a 2.59 times higher risk of showing disease activity.
There were no significant differences in the amount of annual relapses, or time until the first relapse, between the groups in the first two years. Despite this, those who had switched to a moderate-efficacy DMT were more likely to develop active lesions at two years compared with those taking high-efficacy. They were also seven times more likely to get their first lesion sooner than the other group.
The study also found that those in the moderate-efficacy group had around a 20% higher risk of disability progression than those in the high-efficacy group.
The researchers argue that based on these findings, people with MS should start on high-efficacy DMTs when switching from Tysabri.
Source: MS-UK 26 February 2021