Clinical trials in neuroprotection.

Neuroprotection is a therapeutic approach that aims to prevent neuronal degeneration and loss of function. Research has focused on developing neuroprotective agents for the therapy of various degenerative diseases, including Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and glaucoma. Clinical trials for the evaluation of neuroprotective agents pose unique challenges in terms of experimental design and data interpretation. In order to generate meaningful results, clinical trials on neuroprotective agents should ideally be designed to minimize the potential for bias and optimize the ability to detect the neuroprotective effect of a therapeutic intervention in as short a time as possible. Key issues for the design of clinical trials of neuroprotective therapies include identifying appropriate endpoints and determining the ideal timing of the intervention. Neuroprotection trials in glaucoma must be designed to distinguish between the neuroprotective effects of the therapy and the protective effect of intraocular pressure lowering. The choice of suitable functional endpoints in glaucoma trials is also a critical consideration. For example, visual field loss can be used as a functional endpoint; however, it occurs slowly and may require many years before meaningful changes occur. New methods for assessing visual function may be useful for assessing neuroprotective effects of therapeutic interventions. Although there have been a plethora of medications studied for neuroprotective effects in clinical trials, few have been approved by regulatory agencies for use in patients. Despite these challenges, properly designed clinical trials with validated endpoints will yield the most useful information on the neuroprotective effects of therapy, and may provide new treatment options to prevent the loss of neurologic function, including vision.