Switching from Tysabri to another MS medication

August 18, 2015
There has been debate about how to switch patients with multiple sclerosis (MS) from Tysabri to other medications. This happens most often when patients on Tysabri become positive for antibodies to the JC virus. Patients that have these antibodies are at increased risk of a serious infection called progressive multifocal leukoencephalopathy (PML).

Some people believe that patients switching off Tysabri should wait until the Tysabri is completely out of their system before starting another medication to avoid being on two medications at the same time. Others believe that the new medication should be started sooner to avoid MS attacks when coming off Tysabri. The issue is further complicated by the discovery that patients stopping Tysabri may have an increase in attacks that occurs between 3 and 6 months after stopping the drug.

A recent paper from Europe (where most doctors wait until the Tysabri is completely out of a patient’s system) explored the difference in these approaches to switching off Tysabri. Patients were being switched from Tysabri to Gilenya and were divided into three groups, starting Gilenya 8, 12 or 16 weeks after the last Tysabri infusion. The results clearly showed that waiting 16 weeks resulted in more MS attacks. In the 8 week group, 12% had relapses while the 16 week group had 16%. Using MRI to identify relapses, the 16 week group had 4 times the number of active MRI lesions compared to the 8 week group. This study clearly shows that starting the new medication earlier results in better outcomes.

One important point to make is that Gilenya tends to “kick in” very fast, within a few days. Many of the other medications used for MS do not become fully effective for about 2 months. This suggests that it is even more important to switch patients to another medication earlier when using these other medications. Our practice has tried to switch patients at about 4 weeks (when the next dose of natalizumab would normally have been due) and this study supports this practice style.