Cerevance has put its Parkinson’s program back on track with a phase 3 result that the company says supports an FDA filing for solengepras, an oral non-dopaminergic therapy. The readout matters because it follows a phase 2 monotherapy failure last year, when the drug was statistically no better than placebo on a Parkinson’s disease scale by 12 weeks in untreated patients.
In the new study, Cerevance tested solengepras as an adjunctive treatment to levodopa in Parkinson’s patients experiencing motor fluctuations. The company said the GPR6 inverse agonist significantly reduced OFF time, the period when medication wears off and symptoms return or worsen between doses. That is a more commercially relevant setting than the earlier monotherapy attempt because levodopa remains the FDA-approved gold-standard treatment and motor fluctuations are a persistent problem in routine care.
The data
The phase 3 trial enrolled 341 participants who received 150 mg or 75 mg of solengepras, or placebo, orally once daily for 12 weeks. At Week 12, patients treated with 150 mg solengepras showed a reduction in average daily OFF time of 0.61 hours versus placebo, with improvements seen as early as Week 2.
The 150 mg dose also increased ON time by 0.60 hours compared with placebo. Cerevance reported additional patient benefits at that dose, including a 1.91-point increase on a Parkinson’s rating scale for daily living and a 0.98-point improvement in daytime sleepiness versus placebo.
Those added measures matter for how the program may be judged beyond the primary motor readout. Cerevance CEO Craig Thompson said in the company’s release that daily function, alertness and quality of life reflect how people with Parkinson’s experience their day. While that is company framing, it points to the strategic case for solengepras: not just shaving OFF time, but trying to show a broader symptomatic effect in an adjunctive setting.
The road here
Solengepras works through a different mechanism from dopaminergic therapies. Cerevance says it selectively targets the indirect basal ganglia pathway by inhibiting GPR6 receptors, which are enriched in dopamine-expressing neurons. In Parkinson’s, the loss of dopamine leads to hyperactivity of that indirect pathway, effectively acting like a brake on movement. Solengepras is designed to release that brake and restore more normal movement.
That mechanistic distinction is central to the investment case because the program’s value depends on offering something levodopa does not. It also helps explain why the company can present the latest result as a recovery rather than a contradiction of the earlier miss: last year’s failed study evaluated the drug as a monotherapy in untreated patients, while the new trial tested it on top of levodopa in a population already dealing with motor fluctuations.
After the phase 2 failure in April 2025, Cerevance blamed the miss in part on a physician-administered neurological exam that captures physical signs at a single point in time, while pointing to trends in improvement on two patient-reported parts of the endpoint. With the phase 3 win now in hand, the company said it plans to discuss the results with the FDA to determine next steps toward approval.
