Selegiline shown to delay Parkinson's Disease symptom progression

A long-term study has confirmed earlier findings indicating that selegiline delays the progression of the signs and symptoms of Parkinson's disease (PD).The study involved a monotherapy phase and a combination phase. The previously-reported monotherapy phase compared the effect of selegiline with placebo in delaying the need for levodopa therapy in 157 de novo PD patients. The results showed that patients randomised to selegiline had a significantly slower progression of symptoms and a significantly delayed need for the addition of levodopa to therapy. The second phase was a double-blind continuation of the trial whereby 140 patients underwent an 8-week wash-out period before levodopa was added to their initial therapy (selegiline or placebo). The aim of this phase was to compare the progression of PD in patients treated with levodopa plus selegiline with those patients treated with levodopa plus placebo. The patients were followed up until they reached the stage of needing additional dopaminergic therapy or had been on therapy for a total of 7 years. The authors reported, "After 5 years of combination treatment, the mean Unified Parkinson's Disease Rating Scale (UPDRS) total score in patients receiving levodopa and placebo was 10 points (35%) higher than in patients treated with levodopa and selegiline. For the patients, this large difference in UPDRS scores reflects a clinically important difference in their functional capacity." Patients on placebo also needed progressively higher doses of levodopa than patients receiving selegiline. There was also a trend for selegiline to delay the start of wearing-off fluctuations over the 7-year study period (which incorporates the monotherapy phase of the study).The authors suggest a number of possible mechanisms underlying the delay in PD progression with selegiline, including the preservation of dopamine or inhibition of its breakdown. They say that neuroprotective effects are also a possible underlying mechanisms and note, "After 5 to 7 years of follow-up, the mean UPDRS total score remained almost the same as after the initiation of levodopa therapy."Reference...