The clinical significance of these changes is uncertain. Changes in clinical condition were reported using measures of global impression of change. However these were minimal and reliability of the scales used has not been established. No definite changes in disability or quality of life have been demonstrated. Benefits are shown in the first few weeks of treatment, thereafter decline in condition continues at a similar rate as in controls.
Cognitive changes are probably equivalent to about a three to six month delay in progression.
A delay in progression of six months may be equivalent to a gain of approximately 0.05 to 0.08 QALYs. Disbenefits are mild, mainly affecting the gastrointestinal system, and are dose dependent. Unit cost is 891 to 1,248 per year, depending on dose. In the absence of data on treatment cessation, costs were calculated for a range of treatment durations from two to ten years. Individual costs, depending on dose used, range from approximately 2,000 to 10,000 over the expected course of treatment.