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   DIR Return to: TYSABRI (natalizumab)
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       #Post#: 779--------------------------------------------------
       Tysabri review launched in Europe
   DIR By: agate
       Date: May 8, 2015, 6:55 pm
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       From Medscape Medical News, May 8, 2015:
       --- Quote ---
       > Tysabri Review Launched in Europe
       >
       > Pauline Anderson
       >
       >
       > In light of rapidly growing scientific evidence, the European
       Medicines Agency (EMA) has been asked to launch a review of the
       multiple sclerosis (MS) drug natalizumab (Tysabri, Biogen Idec
       Inc.) to assess whether advice on managing known risks for
       progressive multifocal leukoencephalopathy (PML) should be
       revised.
       >
       > PML is a rare brain infection caused by the JC virus (JCV),
       which has symptoms that may resemble those of an MS attack and
       may be fatal or result in severe disability. In addition to the
       presence of anti-JCV antibodies, other risk factors for PML in
       the setting of natalizumab therapy are treatment duration,
       especially beyond 2 years, and immunosuppressant use before
       receiving natalizumab. Patients with all of the above risk
       factors have a significantly higher risk for PML.
       >
       > ...
       >
       > The European Commission has requested the review of
       natalizumab. The review will involve evaluating the data on the
       risk for PML, with the aim of better defining the risk and
       identifying further measures to minimize it.
       >
       > The review will be carried out by the Pharmacovigilance Risk
       Assessment Committee (PRAC), which will make a set of
       recommendations. The PRAC recommendations will then be forwarded
       to the Committee for Medicinal Products for Human Use.
       >
       > The final stage of the review procedure is the adoption by the
       European Commission of a legally binding decision applicable to
       all EU member states.
       >
       > The EMA has recently been made aware of new information in
       three key related issues, a statement from the agency notes:
       >
       > Risk estimates: Natalizumab treatment decisions are based on
       an algorithm in which the estimated PML incidences are
       calculated in a static way by pooling data from all sources
       (clinical studies, registries, spontaneous reports). However,
       interim data from the STRATIFY 2 study for patients with
       positive anti-JCV antibody status with and without a history of
       immunosuppressive treatment suggested a higher risk for PML than
       currently described in the algorithm.
       >
       > "It is therefore appropriate to review the calculations to
       ensure that accurate risk estimates are available for treatment
       decisions" according to background materials provided by the
       EMA.
       >
       > Diagnosis of PML before the development of clinical symptoms:
       New data seem to suggest that asymptomatic PML cases have a
       higher survival rate (95.6%) than do symptomatic cases (77.1%).
       Current recommendations are to perform MRI within 3 months
       before initiating treatment and then annually. Recent literature
       suggests that more frequent MRI testing may detect a greater
       proportion of asymptomatic cases.
       >
       > Anti-JCV antibodies: It was thought that a negative serologic
       anti-JCV antibody test suggested a very low probability of PML
       (about 0.01%), but evidence from the AFFIRM and STRATIFY 1
       studies showed that nearly 13% of negative patients could become
       positive during follow-up.
       >
       > Currently, it's recommended that these patients be retested
       every 6 months for antibodies, but a more sensitive
       second-generation enzyme-linked immunosorbent assay was recently
       developed. Whether this affects current recommendations for
       antibody testing needs to be assessed.
       >
       > Natalizumab is a monoclonal antibody, administered through
       intravenous injection, that is designed to recognize and attach
       to a protein on the surface of leucocytes. By blocking this
       protein, the drug prevents leukocytes from going from the blood
       to the brain, thereby reducing inflammation and nerve damage
       caused by MS.
       --- End Quote ---
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