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

A daily pill for Parkinson's disease has demonstrated significant benefits in a late-stage trial, offering hope for the first major new class of treatment in decades. The drug, solengepras, was shown to substantially reduce the time patients experience "off" periods, characterized by the return of stiffness, slowness, and tremors associated with the condition.

In addition to motor symptoms, the trial indicated that solengepras improved daytime alertness, facilitated everyday tasks such as dressing and eating, and enhanced overall quality of life for patients. This marks a departure from current treatments, which have predominantly focused on dopamine for over 50 years.

Parkinson's disease develops as dopamine-producing nerve cells in the brain are gradually lost, leading to movement impairments. While levodopa, a treatment introduced in the 1960s, and subsequent dopamine-based therapies have been effective, their efficacy can become unpredictable as the disease progresses, often resulting in "off" periods and involuntary movements known as dyskinesia.

Solengepras operates differently by targeting a receptor called GPR6, which is part of a brain circuit that regulates movement. By blocking this receptor, the drug aims to ease an overactive "brake" on movement that can occur when dopamine levels are imbalanced in Parkinson's patients.

The Phase 3 trial involved 341 participants who were randomly assigned to receive either a 75mg or 150mg dose of solengepras, or a placebo, daily for 12 weeks. All participants continued their existing levodopa and other dopamine-based medications.

Results showed that patients taking the higher dose of solengepras experienced approximately 37 minutes less "off" time per day compared to the placebo group and about 94 minutes less "off" time than before the trial. They also gained an additional 36 minutes of "on" time per day without troublesome dyskinesia, relative to the placebo group. Patients on solengepras also performed better on measures of daily activities and reported reduced daytime sleepiness and improved quality of life.

No serious adverse events were reported during the trial, and the rate of treatment discontinuation due to side effects was similar between the solengepras and placebo groups, at 3.5 percent. Dr. Stuart Isaacson, a principal investigator in the trial, highlighted that solengepras could offer a vital alternative as patients often require escalating doses of dopamine-based drugs, which can increase side effects.

Laurence Barker, a partner at SV Health Investors and board member of Cerevance, the Boston-based biotech company behind the drug, expressed enthusiasm for the findings, noting that the early scientific discovery of GPR6 has translated into tangible benefits for patients.

Discussions with US health regulators are the next step, with UK regulatory talks expected to follow. If regulatory processes proceed smoothly, the treatment could become available to patients within two to three years. Approximately 166,000 people in the UK have been diagnosed with Parkinson's disease, with many more believed to be undiagnosed.