General conclusions:
1. All of the products now appear to have evidence that they impact the progression of the disease. However variations in endpoints, definition of endpoints, patient characteristics, and differences in doses (for the interferons) make any comparative evaluation difficult.
2. Copaxone(R) (copolymer 1) possibly has a more profound effect early in the disease and may be more useful in relapsing-remitting MS with little accumulated neurological disability; i.e., possibly more useful early in the disease than later. However, further trials are required to substantiate this conclusion.
3. The new trial results for Betaseron(R) (1-b) are only available in abstract form so critical analysis is difficult. However, the placebo group appeared to be more severe at baseline (13.1% vs. 18.6% of patients at EDSS of 3 to 3.5 while 47.2% vs. 42.5% at EDSS of 6.0 to 6.5) which may account for some of the increased proportion or placebo patients becoming wheelchair bound (seen when EDSS = 7.0).
4. The impact on the rate of acute exacerbations seem to be similar among the different products (approximately 30% reduction). There is some evidence that there is a reduction of moderate and severe attacks. The cost-effectiveness of avoiding one acute exacerbation annually, mentioned in the CCOHTA report, would still be valid and is probably applicable to all the products. This value has been corroborated by an economic evaluation conducted in the UK.
5. Regardless of the methodology used (cost/QALY or cost/EDSS disability years avoided) these drugs are incrementally more expensive for the improvement expected than many interventions currently used in various health conditions.
Conclusions related to Rebif(R):
1. The effect of Rebif(R) on progression was statistically significant, although there were wide confidence intervals indicating a wide variation in individual response. More importantly, the average change of 0.48 is not considered clinically significant.
2. There is no statistically significant difference between the two doses used in the Rebif(R) trial (6 vs. 12 MIU). Since the differences in effect between the doses are not statistically significant, the higher premium for the 12 MIU dose (approximately 21,000 USD) vs. 6 MIU (approximately 17,000 USD) is probably not justified.