Evaluation of clinical benefits of treatments for Alzheimer's disease.

The need for regulatory approval of new therapies for the treatment of Alzheimer's disease-a progressive neurodegenerative condition-has made the assessment of treatment efficacy an urgent priority for discussion and investigation in the field. In the first part of this Personal View, we summarise current views on what constitutes a clinically meaningful benefit from treatment for Alzheimer's disease, including the concept of a minimum treatment effect against which to compare trial outcomes and its limitations. Considering existing and divergent definitions of clinically meaningful change, we define this concept in the second part of the Personal View by proposing a new approach that consecutively considers whether a treatment benefit for Alzheimer's disease is noticeable, valuable, and worthwhile in the context of costs and risks. This approach could be a useful foundation from which the field can move forwards on this issue and address existing gaps in understanding.