Objective: To evaluate long-term effects of 2-year treatment with interferon beta combined with low-dose azathioprine and prednisone in multiple sclerosis. Methods: In the original 2-year ASA study, 181 patients with early relapsing-remitting multiple sclerosis were randomised into 3 treatment arms: those treated with interferon beta (n = 60), with interferon beta and low-dose azathioprine (n =58), and interferon beta, azathioprine and low-dose prednisone (n = 63).
Of these, 172 were included in this 4-year non-study extension. Three monthly clinical controls and annual MRI scans were carried out.
The primary endpoint was annual relapse activity. The secondary endpoints were disability and quantitative MRI parameters.
Results: Nine patients were lost to follow-up and 172 were included in the analyses. None of relapse activity, disability accumulation or MRI parameters differed significantly between the groups over 6 years.
Only 5.5% and 0.6% of patients were free from disease activity at year 2 and year 6 of the treatment initiation. Conclusion: The tested combined therapeutic regimen does not improve long-term outcomes in patients with multiple sclerosis.
Furthermore, interferon is not able to completely abolish disease activity.