The drawback in the new immunotherapies in multiple sclerosis (MS) includMe severe infections that can be fatal. For example, treatment with natalizumab, which reduces the immune surveillance of the brain, can lead to the development of progressive multifocal leukoencephalopathy (PML), a typically fatal form of viral encephalitis. Prof. Ralf Gold (RUB Clinic for Neurology, St. Josef Hospital) and Dr. Werner Wenning (Ortenau Clinic, Offenburg-Gengebach) employed plasmapheresis to eliminate the active pharmaceutical agent and thus clear the virus from the brain. A report on their successful method of treatment has been published in the current edition of the New England Journal of Medicine.
Suppressing the destructive impact of leukocytes in MS
Natalizumab is a monoclonal antibody that has been approved for the treatment of severe RR‑MS (relapse remitting MS) in the EU since 2006. The antibody attaches to specific structures on the surface of white blood cells thus reducing their ability to attach to and pass through vascular wall into the inflamed tissue. The active agent thus suppresses the destructive effects of leukocytes that attack the myelin sheath, the insulating layer of nerve fibres. Leukocytes theoretically attack and destroy destructive foreign substances such as viruses or bacteria, thus the drawback of this medication is a decrease in the immune defense of the brain.
Unfulfilled hope: monotherapy is also not harmless
Clinical studies with Natalizumab led to progressive multifocal leukoencephalopathy (PML) in two MS patients. This severe brain infection is triggered by the JC virus found in about 80% of all adults. Normally the immune system does however control the virus. Less experienced physicians can easily mistake PML symptoms with an acute attack of MS. Prof. Gold explained that both study patients had also been administered the immune activating drug Interferon Beta, thus the hope that the monotherapy was relatively harmless had been realistic. Moreover, when the drug was approved at the beginning of summer 2006, the manufacturing company BiogenIdec had offered country-specific intensive preparatory seminars covering almost all precautionary and therapeutic measures. In July 2008, PML was diagnosed almost simultaneously in a German and Swedish MS patient, after 14 and 16 months of Natalizumab treatment respectively.
Treatment in Offenburg, supervision in Bochum
The strategies of treating the infection are the topic of the two studies that were simultaneously submitted for publication by the German and Swedish authors. The German patient was treated by Dr. Werner Wenning in Offenburg, and the therapy supervised by Prof. Gold in Bochum.
Plasmapheresis eliminates the active agent natalizumab