Fingolimod After Natalizumab & Short-term Relapse Risk

Dr Vilija Jokubaitis et al

Natalizumab (Tysabri) is an antibody used for the treatment of multiple sclerosis (MS). It is currently the strongest drug available for the treatment of MS, however, it has also been linked to a small number of cases of progressive multifocal leukoencephalopathy (PML). Fingolimod (Gilenya) is a relatively new MS treatment and has become a common choice for people with MS who have not responded to a first-choice therapy or are at risk of developing PML. Recently, it was reported that a small number of people who transferred from Tysabri to Gilenya experienced a large increase in relapses in the first 6 months on Gilenya, whereas some people also reported having very severe relapses on Gilenya.

To determine whether this occurrence was linked to the move from Tysabri to Gilenya, this study utilised the independent MSBase registry database to examine 536 people with MS using Gilenya for the first time. The study investigated the relapse rate from people in three different groups:

1. People on Tysabri moving to Gilenya
2. People on interferon-beta/Copaxone moving to Gilenya
3. People taking Gilenya as a first ever treatment for MS

The results indicated that the relapse rate after the switch to Gilenya was low in all groups. Relapse activity in the 6 months prior to treatment with Gilenya was found to be the best predictor to future relapse rate. Based on this study, the investigators suggested a maximum 2 month gap when switching from Tysabri to Gilenya to decrease the potential for relapse (this gap is not required when switching from injectable medications). The severe relapses and increased relapse activity reported in other studies could, therefore, be a result of very long treatment gaps between Tysabri and Gilenya or it could be the result of a Gilenya-specific side effect in a very small number of patients. People with MS should be reassured that, in most cases, switching from Tysabri to Gilenya is safe and does not result in increased relapses.