Last Updated: 2008-06-10 15:16:37 -0400 (Reuters Health)

NEW YORK (Reuters Health) – During the initial stages of interferon beta treatment in patients with relapsing-remitting MS, monitoring by means of MRI scans and anti-interferon beta neutralizing antibodies (NAb) can be useful in predicting clinical response, Italian researchers report in the June issue of the Journal of Neurology, Neurosurgery and Psychiatry.

"Either having an MRI scan with signs of disease activity or a positive NAb test will predict a bad clinical response over the next 2 years of interferon beta treatment," lead investigator Dr. Luca Durelli told Reuters Health.

Dr. Durelli of Ospedale San Luigi Gonzaga, Turin and colleagues came to this conclusion after studying 147 patients who underwent repeated MRI scans and NAb assays during the first 6 months of interferon beta therapy.

The researchers found a positive scan had a predictive sensitivity of 52% and a specificity of 80% for clinical disease activity in the following 18 months. The negative predictive value was 73% and the positive predictive value was 62%.

For NAb positivity, the corresponding values were 71% and 66%, and 92% and 29%. The combination of an active scan and NAb positivity had a sensitivity of 71%, a specificity of 86%, a negative predictive value of 94% and a positive predictive value of 50%.

In other words, continued Dr. Durelli, "Patients developing both MRI activity as well as NAb positivity carry a 50% risk of developing clinical activity…. This could be an indication to switch them to a different immune-modulatory or immune-suppressive treatment."

In an accompanying editorial, Drs. Hans-Peter Hartung of Heinrich-Heine-University Dusseldorf and Joep Killestein of VU University, Amsterdam, express reservations about the findings, but nevertheless conclude that "it is a useful prospective study providing evidence of the existence of biomarkers that aid in identifying suboptimal interferon beta responders at an early stage."

J Neurol Neurosurg Psychiatry 2008;79:616-617.

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