Trials of extension trials PRISMS

neurology practice guidelines: "Extension trials-- limited benefit
Noseworthy JH How much can we learn from long-term extension trials in multiple sclerosis? Neurology 2006; 67: 930-931 editorial

comments on Kappos et al. Long term interferon beta 1a therapy in patients with relapsing MSNeurology 67: 944-953 2006

32 % patients randomized in PRISMS did not participate in the extension. Blinding was eliminated. Visits were in some cases conducted every two years or retrospecive evaluations were substituted. About 25 % patients entering extension did not remain on treatment. Brain atrophy was not reduced. The NTT (number to treat) early v 24 months later to prevent one point progression on EDSS was 27. Conclusion of safety is warranted, not that of efficacy.

Kappos et al-- 382 patients followed 8 years. 19 % progressed to spms. NABS generally disappeared with treatment. The authors claim 44 dose worked better than 22. 396/560 patients had EDSS < 3 at baseline; of those, 27 % went to EDSS of 4, 20 % went to an EDSS of six, 12 % to 6.5, and 6 % to edss of 7.

Relapse rate was about .61 per patient per year in treated patients."