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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 two 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 six months of interferon beta therapy.

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

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

In other words, continued Dr. Durelli, "Patients developing both MRI activity as well as NAb positivity carry a 50 per cent 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."