PRISMS-4

PRISMS-4: Long-term efficacy of interferon B1a in relapsing MS. The PRISMS Study Group Neurology 2001:56:1628-1636

Have 2 years double blind and another 2 years of dose blind assessment.Placeo patients at end of frist two years were rerandmoized to rebif 22 or rebif 44

90% of patients continued to PRISMS 4 . Relapse rate, time to first relapse, time to progression of disability all favored high dose rebif and initial treatment wih high dose rebif. High dose was associated with 29% fewer 1 point edss changes over 4 years compared to crossover. Time to EDSS progression was not significant in low dose rebif in ITT analysis.

Lab changes (liver, CBC) were also more common in high dose group .

Burden of disease increased in years 3 and 4 for high dose group.