MIAMI BEACH — Early treatment of people with Parkinson's disease with the dopamine receptor agonist pramipexole does not significantly modify the course of disease at 15 months, according to a phase I/II study with 535 participants.
“Pramipexole is an effective symptomatic drug, but this study does not show that early treatment is disease modifying,” Dr. Anthony Schapira said at the World Federation of Neurology World Congress on Parkinson's Disease and Related Disorders.
Pramipexole is approved by the Food and Drug Administration for the treatment of the signs and symptoms of idiopathic Parkinson's disease and for primary restless legs syndrome.
A total 261 patients were randomized to 6–9 months of pramipexole (Mirapex) and comprised the early treatment group. Another 274 patients took a placebo during this phase, and then all of the patients took pramipexole up to 15 months. The primary outcome of the Pramipexole on Underlying Disease (PROUD) phase I/II study was the change in Unified Parkinson's Disease Rating Scale (UPDRS) total score at the end of 15 months compared with baseline. The study was sponsored by the manufacturer of Mirapex, Boehringer Ingelheim GmbH. The drug also is available in generic form.
The mean age in each group was 62 years, and the mean duration of Parkinson's disease at baseline was 1.8 years. Total UPDRS scores were based on parts I, II, and III of the instrument. Treated patients only took the dopamine agonist; no rescue drugs were allowed.
The dopamine agonist was dosed at 1.5 mg/day. “At this dose of pramipexole, there was no difference in UPDRS or imaging finding between early and late onset,” Dr. Schapira said. The difference in adjusted mean total score between groups was only 0.4 UPDRS units at 15 months, a nonsignificant finding.
“Early improvement was seen in the early [treatment] group, but then there was a decline. In the late group, [the patients] were initially worse but responded and ultimately ended up at the same point at 15 months,” said Dr. Schapira, head of the department of clinical neurosciences at University College London. He had no relevant disclosures.