Challenges to Drug Development for Neurologic Conditions In developing treatments for neurologic disorders, researchers and clinicians face several challenges related to both disease state and conducting clinical trials. Limits in understanding the science of neuropathologies. Drug development works best when the mechanisms of a pathology are understood. When information regarding the pathology is lacking, it is difficult to develop novel mechanisms to block the disease, and it can be even more challenging to determine whether a therapy is working. For some neurologic diseases, including Alzheimer disease, few animal models exist (Pritchard, 2008). Alzheimer disease is also challenging because no single mechanism that drives disease has been found. Having limited insight into a disease’s pathology hinders application of data from animal studies to the care of humans (Brunner, 2012, Craven, 2011; Pangalos, 2007; Shineman, 2009). Dr. Mark Stacy, Vice Dean for Clinical Research at Duke University Medical Center notes that a “lack of a thorough understanding of disease pathogenesis is similar to blind-folded physicians examining different parts of an elephant with each coming to a different diagnosis.” Results of the human genome project have provided many potential targets for drug development (Preskorn, 2011). However, the potential targets are so numerous it is difficult to know which ones to pursue. Regulatory requirements. The stringent requirements imposed by regulatory bodies on all phases of drug development represent substantial barriers to developing new drugs for neurologic conditions (Craven, 2011; Kaitin, 2010; Richards, 2008; Shineman, 2009; Steinmetz, 2009). For example, researchers must decide on a research design and all safety and efficacy endpoints before beginning a study. Although this approach allows researchers to closely control variables that might affect study results, there is an inherent risk that exploration of novel endpoints may reveal effects that were not expected (Brunner, 2012). Dr. Stacy notes that “regulatory requirements such as approval by multiple institutional review boards, development of complex study designs, training investigators, and establishing contracts with other agencies and clinical centers to recruit eligible patients and implement the study protocol” are significant hurdles that many researchers simply cannot overcome without assistance.