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RRMS Patients at Risk of PML Can Safely Switch from Tysabri to Lemtrada

September 11, 2017

Tysabri (natalizumab), an antibody with anti-inflammatory action, has been shown to increase the risk of a rare opportunistic viral infection of the brain called progressive multifocal leukoencephalopathy (PML). But an Italian study shows that another treatment, Lemtrada (alemtuzumab), may be an effective option for relapsing-remitting multiple sclerosis (RRMS) patients withdrawing from prior treatment with Tysabri. The study, “High-Risk PML Patients Switching from Natalizumab to Alemtuzumab: an Observational Study,” was published in the journal Neurology and Therapy.

The study aimed to investigate whether MS patients stopping their treatment with Tysabri could safely switch to Lemtrada. Lemtrada, an antibody therapy, specifically targets the CD52 protein, which is present on the surface of certain immune cells, such as T- and B-cells, thereby blocking their action. It is given as intravenous infusions for five consecutive days initially, and for three consecutive says one year later. The study took place at the University Hospital San Luigi Gonzaga of Orbassano and consisted of 16 patients. These patients received a median of 20 Tysabri infusions before quitting the treatment due to an increased risk of PML. Patients took Lemtrada after a median wash-out period of 70 days. Patients then had a brain MRI every three months while on Tysabri and shortly after starting Lemtrada treatment, to check for signs of PML.

The study is currently ongoing. Those who have received Lemtrada for at least six months or for one year showed no sign of disease activity or new lesions. They have also neither relapsed nor worsened on the Expanded Disability Status Scale, a measure that quantifies disability in patients with MS. Although this study includes only a small number of patients, researchers concluded that the study’s “initial data are very promising as no patient had radiological signs or clinical symptoms of disease reactivation/progression, no patient experienced severe side effects and no patient developed PML.”