, new research suggests. Results from a phase 3 trial of P2B001, a combination of pramipexole and rasagiline at currently unavailable low doses, showed the drug was more effective than its individual components and as effective as higher-dose pramipexole ER – with far less daytime sleepiness.
The combination drug is taken once per day and does not require titration, which investigators say make it a good option for first-line treatment of Parkinson’s disease.
“I don’t think people, including me, expected intuitively that if you used small doses and combined it with a little rasagiline it would be equal to full doses of pramipexole, but it appears that it is,” said lead investigator Warren Olanow, MD, professor and chair emeritus of neurology and professor emeritus of neuroscience at Icahn School of Medicine at Mount Sinai, New York.
The findings were presented at the 2022 annual meeting of the American Academy of Neurology.
Levodopa is considered to be the most effective treatment for Parkinson’s disease, but long-term use is associated with increased risk for motor complications, such as dyskinesia. Dopamine agonists such as pramipexole have been linked in previous research to excessive daytime sleepiness and impulse control disorders. In addition, monoamine oxidase-B inhibitors such as rasagiline are not as effective at controlling Parkinson’s disease as other treatment options.
“There is no consistent agreement on how to initiate treatment because no one treatment is ideal,” Dr. Olanow said.
P2B001, developed by Pharma Two B, is a combination of 0.6 mg of pramipexole and 0.75 mg of rasagiline. The drugs work by dual mechanisms, which investigators suspected might have “synergistic effects.”
Following promising results from an earlier trial, researches launched a phase 3, 12-week, international, randomized, double-blind trial to study the efficacy, safety, and tolerability of P2B001, compared with its individual components and with a calibration arm of pramipexole ER in 519 patients with early Parkinson’s disease.
Participants received P2B001, 0.6 mg of pramipexole ER, 0.75 mg of rasagiline ER, or pramipexole ER titrated to an optimal dose for each patient (1.5-4.5 mg).
New first-line treatment?
Results showed that the adjusted mean change from baseline in total Unified Parkinson’s Disease Rating Scale (UPDRS) score was -2.66 points for P2B001 versus pramipexole (P = .0018) and -3.30 points for P2B001 versus rasagiline (P = .0001).
There was no significant difference in UPDRS scores between P2B001 and pramipexole ER, but patients who received P2B001 reported significantly less daytime sleepiness.
The adjusted mean change from baseline in Epworth Sleepiness Scale score for P2B001 versus pramipexole ER was -2.66 points (P < .0001).
In addition, fewer dopaminergic adverse events were reported with the combination drug versus pramipexole ER (44.7% vs. 66.2%), including somnolence (14.7% vs. 31.1%) and orthostatic hypotension (2.7% vs. 12.2%).
As a first-line treatment, P2B001 could offer an effective option instead of levodopa, Dr. Olanow said. “It could be really good for patients because it would delay the introduction of levodopa and allow levodopa to be used in lower doses when the time comes and hopefully reduce the risk of complications,” he added.