Effect of drugs in secondary disease progression in patients with multiple sclerosis.

Secondary progressive multiple sclerosis (SPMS) is a form of MS characterized by continuously worsening disability with or without superimposed relapses that occurs after a variable period of relapsing remitting disease and results in limited ambulation for almost all patients. The use of interferon beta (IFN beta) for immunomodulation in patients with SPMS has been evaluated in four recent clinical trials: The European multicentre trial on IFN beta-1b in SPMS (EUSPMS), the Secondary Progressive Efficacy Trial of Rebif (IFN beta-1a) in MS (SPECTRIMS), the North American Study of IFN beta-1b in SPMS (NASPMS), and the International MS Secondary Progressive Avonex Clinical Trial (IMPACT). EUSPMS was the only trial to demonstrate a significant positive effect of therapy on disease progression as measured by the expanded disability status scale (EDSS). However, results from all studies demonstrated significant positive effects of treatment on relapse, T2 lesion load, and gadolinium enhancement. Immunomodulation with IFN beta has the potential to significantly slow disease progression and improve quality of life for patients with SPMS. While results with monthly i.v. Ig were disappointing, positive effects on disease progression have been reported with the application of immunosuppressants, especially Mitoxantrone. The risk-benefit ratio of these cytostatic agents remains controversial. New strategies addressing the important neurodegenerative aspects of the disease are urgently needed.