DOES SELEGILINE DELAY PROGRESSION OF PARKINSONS-DISEASE - A CRITICAL REEVALUATION OF THE DATATOP STUDY

The deprenyl and tocopherol antioxidative treatment (DATATOP) study ha s shown that selegiline (deprenyl), with or without tocopherol, reduce s physical and psychological deficits in patients with Parkinson's dis ease within one month of treatment and reduces the probability of reac hing a primary endpoint, the decision to treat with levodopa. This pap er critically re-evaluates the inference that selegiline has a neuropr otective effect and thus delays progression of Parkinson's disease. An alysis is based on a simple model which assumes that clinically measur ed impairment is proportional to degree of cellular dysfunction in Par kinson's disease. The analysis suggests that the reduced probability o f reaching an endpoint was due to a direct treatment effect rather tha n to neuroprotection.