The evidence for disease modification in Parkinson's disease

Disease modification or slowing the progression of any neurodegenerative disorder represents a dire unmet need. There have been trials for several decades specifically designed to help evaluate whether a specific therapy might be able to slow the progression of Parkinson's disease (PD) or be disease modifying. Trials evaluating the use of coenzyme Q10, pramipexole, and levodopa suggest that these medications offer symptomatic benefit uniquely, while other studies reveal that rasagiline and selegiline may be disease modifying. This review will discuss in detail the design and results of clinical trials for varied medical therapies that were specifically undertaken to discern whether a particular treatment might be disease modifying in the treatment of PD.