Alzheimer drugs – the evidence is (still) not convincing

In 2005 our research group (Institute for Primary Medical Care, Center of Psychosocial Medicine, University Medical Center Hamburg-Eppendorf, Hamburg) published a highly controversial paper in the British Medical Journal: Cholinesterase inhibitors for patients with Alzheimer’s disease: systematic review of randomised clinical trials.

We analyzed the evidence of 22 published trials on the drugs donepezil (marketed as Aricept), rivastigmine (marketed as Exelon) and galantamine (marketed as Reminyl) and concluded, „the scientific basis for recommending donepezil, rivastigmine, or galantamine as preferred treatment for patients with Alzheimer’s disease is questionable because minimal benefits were measured on rating scales and the methodological quality of the available trials was poor.“

Our review stood in strong contrast to the reviews of the Cochrane Library of Systematic Reviews. As these reviews are usually seen as the „Gold standard of reviews“, our paper drew a whole lot of attention. Hence, this spring the debate is carried forward in the journal International Psychogeriatrics.

We were invited by the editor of the journal, David Ames, to debate the issue and to reflect once again our point of view. Mr. Ames also invited Jacqueline Birks, one of principal investigators of the Cochrane reviews on donepezil and rivastigmine, to explain the readers her conclusions.

This time we summed our paper as follows:
1. We need to develop better methods of quality assessment of clinical trials.
2. Trial data from industry should be accessible for research purposes.
3. Further research directed at the recognition of high responders before initiation of therapy with cholinesterase inhibitors is needed.
4. Against the background of the disappointing results of the trials, we need clear rules concerning initiation, evaluation and termination of therapy.