How effective are second generation DMTs?
In general, both natalizumab and fingolimod are more effective than the interferons and glatiramer acetate. For natalizumab, there are significant risks. Natalizumab a monoclonal antibody that’s infused once every four weeks. In the clinical trials Natalizumab is 60% effective in reducing the frequency of relapses, compared to 33% for the interferon and glatiramer acetate. Natalizumab also decreases the risk of disability over the long term a bit more than the first generation drugs. It definitely looks more effective, so why isn’t everyone on this drug? The reason is, because of some serious side effects. The most serious is that patients taking natalizumab are at risk of developing a rare very serious viral infection of the brain called "Progressive Multifocal Leukoencephalopathy" or PML. It is caused by a virus, the JC virus and over 200 people who have received natalizumab for MS have now developed this infection. 20% of patients who develop PML die and the rest generally are quite disabled. Some other infections have been described with natalizumab and maybe associated with some lymphomas and other cancers, but the big concern is the PML. There’s a special program called the TOUCH Program that the company that markets natalizumab has in the US. Every patient in the US on this drug has to be registered in the TOUCH Program and they’re tracked and checked periodically to monitor for serious side effects. We have really good data on the occurrence in particular of the PML in patients receiving natalizumab. Because the drug looks so good in controlling the disease and we have to deal with the PML, a lot of work has gone into try to risk stratify. Is there a way we can predict who’s a greater risk in others in terms of developing the PML? We have found out that there are three factors that influence the risk.
PML Risk Factors
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