Serum samples were analyzed with an immunoassay from 239 randomly selected patients treated with interferon beta-1b, 250 micrograms, for at least 2 years in the Betaferon Efficacy Yielding Outcomes of a New Dose Study. Researchers measured the levels of IL-17F at baseline and month 6, as well as the difference between the IL-17F levels at month 6 and baseline were compared between: (1) patients with less disease activity versus more disease activity; (2) patients with no disease activity versus some disease activity; and (3) responders versus nonresponders.

According to study results,levels of IL-17F measured at baseline and month 6 did not correlate with lack of response to treatment after 2 years using clinical and magnetic resonance imaging (MRI) criteria. Relapses and new lesions on MRI were not associated with pretreatment serum IL-17F levels. When patients with neutralizing antibodies were excluded, the results did not change.

"We found that serum concentrations of IL-17F alone did not predict response to interferon beta-1b therapy in patients with relapsing-remitting multiple sclerosis." The study concludes, "Given the multifaceted pathophysiology associated with disease progression and response to treatment by patients with relapsing-remitting multiple sclerosis, using extreme patient cohorts in combination with immune-based biomarker signatures may actually be the most efficient way of initially identifying response markers."