Phase 3 trial of solengepras for Parkinson’s disease now fully enrolled

Enrollment is now complete in a Phase 3 trial assessing the safety and efficacy of solengepras (CVN424), Cerevance’s experimental non-dopaminergic therapy, in people with Parkinson’s disease.

The Phase 3 ARISE trial (NCT06553027) is assessing solengepras’ efficacy, when given with levodopa and other standard Parkinson’s medications, in 341 patients with motor fluctuations who have an average of three or more hours of total off time per day. The trial is being conducted at 94 sites in the U.S., Europe, the U.K., and Australia, and topline data are expected later this year.

“With ARISE fully enrolled and our oversubscribed Series C secured with strong support from our existing investors, we are funded through topline data and poised to deliver what could be the first non-dopaminergic therapy to reach patients in decades,” Craig Thompson, Cerevance’s CEO, said in a company press release.

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Solengepras targets off time differently

Parkinson’s disease is caused by the progressive loss of dopaminergic neurons, the nerve cells that produce dopamine, a chemical messenger essential for muscle control. Levodopa, a precursor to dopamine, is a mainstay treatment for Parkinson’s.

However, its long-term use can lead to off periods, when Parkinson’s symptoms return between treatment doses, and dyskinesia, or sudden, involuntary movements.

Solengepras is a small oral molecule designed to enter the brain and act on nerve cells in the striatum, a region critical for controlling voluntary movement. The experimental therapy works by selectively blocking GPR6, a protein receptor found on specific nerve cells within the striatum. By inhibiting GPR6, solengepras is designed to mimic some of the benefits of levodopa without directly altering dopamine levels, potentially reducing side effects such as dyskinesia.

“Motor fluctuations remain one of the most persistent and disruptive challenges in disease management, with current therapies leaving a substantial gap in care,” said Stuart H. Isaacson, MD, director of the Parkinson’s Disease and Movement Disorders Center of Boca Raton and principal investigator of the ARISE trial. “The ARISE trial is designed to rigorously evaluate solengepras’ impact on OFF time in patients receiving standard-of-care therapy, and we look forward to seeing the data later this year.”

Results from a Phase 2 trial (NCT04191577), which enrolled adults with Parkinson’s experiencing at least two hours per day of off time despite treatment, demonstrated solengepras significantly reduced off time compared with placebo when used as an add-on to levodopa. It also increased good on time, when symptoms are well controlled with levodopa without troublesome dyskinesia, and showed signs of reducing daytime sleepiness.

Earlier trials showed potential benefits

In the Phase 2 ASCEND trial (NCT06006247), which evaluated the treatment in adults with early, untreated Parkinson’s disease who had not previously received dopaminergic or other Parkinson’s therapies, solengepras showed potential benefits on functional and nonmotor symptoms when used alone.

Participants in the ARISE trial were randomly assigned to receive one of two doses of solengepras, 75 or 150 mg, or a placebo, once daily for 12 weeks (about three months). The trial’s main goal is to evaluate whether the higher treatment dose can reduce off time after three months of therapy. Secondary objectives include solengepras’ safety and tolerability, as well as its effects on on time, daytime sleepiness, cognitive function, and several quality-of-life measures.

After completing the trial, participants can enter an open-label extension study assessing solengepras’ long-term safety and efficacy.