Neuroprotection in Parkinson's disease: myth or reality?

Parkinson's disease (PD) is a chronic, progressive, neurodegenerative disorder with no cure. Therapies that delay or halt disease progression are urgently needed, but finding such therapies has been difficult. In this article, we review historical and recent clinical trial work in the field of neuroprotection. Several issues have arisen during the search for disease-modifying therapies, including challenges in selecting appropriate therapeutic targets, assessing potential therapies, and selecting the proper patient population to study. Advances in the understanding of PD pathogenesis are presented as they relate to selecting potential therapeutic targets, and issues with preclinical testing are described. We review recent innovations in clinical trial design, including futility studies and delayed-start designs that promise to make clinical testing more efficient. It is hoped that ongoing work in this field will lead to treatments that delay the progression of PD.