Solengepras: a new approach to OFF periods, without dopamine

For months I have been following the phase 3 ARISE trial of solengepras, a drug from the US company Cerevance. The results are now in, and I would like to put them into context for you.

What is it about?

Almost all Parkinson's drugs act on dopamine: they replace it (levodopa), imitate it (agonists) or make it stay in the brain longer. Over the years, many people with Parkinson's get to know the problem of motor fluctuations. Good ON periods are followed by OFF periods in which the symptoms return, often together with involuntary movements (dyskinesias).

Solengepras takes a different route. It blocks the GPR6 receptor, which sits in a movement network of the brain that works independently of dopamine. It is taken once a day as a tablet and is meant as an add-on to existing treatment, not as a replacement.

The trial

• Phase 3, randomized, double-blind, placebo-controlled, international
• 341 participants with motor fluctuations and at least three hours of OFF time per day (5.65 hours on average)
• Three groups: 150 mg, 75 mg or placebo, each once a day for 12 weeks
• 91 percent completed the trial as planned
• Presented in October 2026 at the International Congress of the Movement Disorder Society in Seoul; the company published the results on 7 October

The results

• With 150 mg, daily OFF time fell by 1.56 hours, with placebo by 0.95 hours. The real benefit of the drug is therefore about 37 minutes per day. The primary goal of the trial was met.
• The effect was already visible from the second week.
• Good ON time without troublesome involuntary movements rose by about 36 minutes more than with placebo.
• Everyday functioning (MDS-UPDRS Part 2) also improved measurably.
• Tolerability: there were no serious side effects in the 150 mg group. Headaches, sleep problems and nausea were more common than with placebo. Dyskinesias occurred in 4.4 percent (placebo 1.8 percent).

My assessment

I think it is good that a drug against motor fluctuations is finally coming that does not turn yet another dopamine screw. To be honest, though, the effect is modest. 37 minutes less OFF time a day is noticeable for people with strong fluctuations, but it is not a breakthrough. It is also remarkable how strongly the placebo group responded, which shows how important well-controlled trials are.

Important: as far as we know today, solengepras does not slow the progression of the disease. It relieves symptoms, nothing more. The trial also lasted only 12 weeks, and long-term data are still missing.

For me personally the drug plays no role at the moment, because I do not take conventional Parkinson's drugs and therefore do not have OFF periods in the classic sense. For many of you who live with levodopa, however, it could become an additional option in a few years.

What happens next?

Cerevance now wants to discuss the results with the US Food and Drug Administration (FDA). There is no timetable for an application for approval yet, and in Europe the drug is still a long way off. I will stay on it. A short overview of other news is available under Research 2026.

Sources

• NeurologyLive: Solengepras meets primary endpoint in Phase 3 ARISE trial
• Cerevance: press release of 7 October 2026

Note: This article describes my personal view and is not medical advice. Please always discuss changes to your treatment with your neurologist.