New Parkinson's Drug Shows Promise in Late-Stage Trial

A daily pill for Parkinson's disease, named solengepras, has shown significant benefits in a late-stage trial, offering hope for the first major new class of treatment for the condition in over 50 years.

The drug demonstrated a notable reduction in the time patients experienced "off" periods, characterized by the return of stiffness, slowness, and tremors associated with Parkinson's. The trial also indicated improvements in patient alertness, ease of performing daily tasks, and overall quality of life.

Solengepras operates differently from existing Parkinson's medications, which primarily focus on dopamine, a brain chemical crucial for movement that is depleted in individuals with the disease. Instead, solengepras targets a different part of the brain's motor system by blocking a receptor called GPR6. This receptor acts as a brake on movement, and in Parkinson's, the imbalance caused by dopamine loss can lead to this brake becoming overly strong.

The Phase 3 trial involved 341 participants who continued their existing levodopa and other dopamine-based treatments. Those receiving the higher dose of solengepras experienced approximately 37 minutes less "off" time per day compared to the placebo group. Additionally, they gained about 36 minutes of "on" time without troublesome involuntary movements, known as dyskinesia, compared to the placebo group. Patients on solengepras also performed better on scales measuring daily activities and reported less daytime sleepiness.

No serious adverse events were reported during the trial, and the rate of patients discontinuing treatment due to side effects was the same as in the placebo group.

"This is the first positive phase three study for a non-dopaminergic mechanism for a very long time," said Laurence Barker, a partner at SV Health Investors and board member of Cerevance, the biotech company behind the drug. He added that the scientific discovery of GPR6 has translated into tangible benefits for patients.

Dr. Stuart Isaacson, a principal investigator in the trial, noted that patients often need increasingly frequent and higher doses of levodopa, which can exacerbate side effects like dyskinesia. He believes the new treatment offers a much-needed alternative and "gives great hope for the future."

Parkinson's disease affects approximately 166,000 people in the UK, with an unknown number of others living with the condition undiagnosed. The progressive brain disorder develops as dopamine-producing nerve cells are gradually lost, leading to slower movement, stiffness, and tremors.

Levodopa, introduced in the 1960s, remains a cornerstone of Parkinson's treatment by replenishing dopamine. However, its effectiveness can diminish as the disease progresses, leading to unpredictable "off" periods and dyskinesia.

Cerevance plans to engage with US health regulators in the near future, with discussions with UK regulators to follow. If regulatory processes proceed smoothly, solengepras could be available to patients within two to three years.