Natalizumab anti-drug antibodies

Indication

Natalizumab (Tysabri) anti-drug antibodies (ADA) has been found in 4.5 to 14.1% of natalizumab-treated multiple sclerosis (MS) patients. High levels of antibody titers indicate a risk for persistent natalizumab ADA which is associated with a negative effect on the response to treatment.

Method

Serum samples are analyzed using an immunoassay on a Meso Scale Discovery (MSD) platform. MSD assays have high detection sensitivity but it is still recommended that the sample is taken at the Cmin, when the drug concentration is lowest. The sample will be answered as negative or positive and a follow up for the level of antibody titers.

Interpretation

In the event of a positive sample it is recommended to collect a new sample within 4-8 weeks to verify the positivity and if the patient is persistent positive. Treatment with natalizumab should be continued until the follow up test is confirmed positive or negative, unless hypersensitivity noted. If the verification test is positive, treatment should be discontinued.

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References

Lundkvist et al. Characterization of anti-natalizumab antibodies in multiple sclerosis patients. Mult Scler. 2013 May;19(6):757-64

Vennegoor et al. Clinical relevance of serum natalizumab concentration and anti-natalizumab antibodies in multiple sclerosis. Mult Scler. 2013 Apr;19(5):593-600.

Clinical studies