The study enrolled 36 patients who were assessed for indicators of cognitive performance such as memory, orientation, language, attention and reasoning. The results were assessed using a cognitive score on the Alzheimer's disease Assessment Scale, the so-called ADAS-cog score. The scores range from 0 to 70, with lower scores indicating a healthy adult. As dementia progresses, the score increases. Eighteen of the patients were assigned to placebo and 18 received Prana's Alzheimer's disease drug, PBT-1 (Clioquinol) (the first of Prana's metal protein attenuating compounds (MPACs) to be developed for Alzheimer's disease). PBT-1 is a chemical that binds zinc and copper, and has been shown to lower the levels of A and the associated toxicity in the brains of Transgenic mice used as a model of Alzheimer's Disease.
The more affected patients entering Prana's pilot clinical trial (i.e. those with higher ADAS-cog scores) showed an average change in score at 24 weeks of about 1.5 points on PBT-1 and about 8.9 on placebo, a difference of 7.4. Generally, untreated patients with mild to moderate disease could be expected to gain six to 12 points in their ADAS-cog score over 12 months. A panel convened by the Food and Drug Administration in the US deemed an improvement of four points would be clinically significant.
"The results of this trial have been very encouraging to a clinician," said Dr Ritchie of UCL who led the study, adding; "Our findings have led to the development by Prana Biotechnology of new, possibly more effective drugs which hit the same target as Clioquinol. UCL plans to be involved in further testing of the principal using Clioquinol in a larger, UK multi-centre study which is seeking public funding."
Dr Susanne Sorensen, Head of Research at the Alzheimer's Society says: "The Alzheimer's Society welcomes this research as the results indicate that there may be a novel use for this already existing drug in the treatment of Alzheimer's disease. The trial presented here is limited in its scale and the Alzheimer's Society believes it would be valuable to see a larger scale trial. The potential for new drugs that may interfere with or revert the progression of Alzheimer's disease gives hope to people with dementia and their carers. There are currently only limited and expensive treatment options available for Alzheimer's disease and none that revert the disease for more than a short period."