Proof-HD (Prilenia)


about the study

PROOF-HD is a global Phase 3, randomized, double-blind, placebo-controlled, parallel arm, multicenter study evaluating the efficacy and safety of pridopidine in patients with early stage HD.

Sponsor: Prilenia Therapeutics


about the experimental drug  

Pridopidine is a highly selective Sigma-1 receptor (S1R) agonist. It binds and activates the S1R, a protein that is expressed at high levels within the brain and regulates key cellular pathways, commonly impaired in neurodegeneration.

Pridopidine, by activation of the S1R, demonstrates beneficial effects in numerous cellular and animal models of HD. For example, pridopidine rescues neurons from mutant Huntingtin (mHTT) induced cell death, in HD patient-derived induced Pluripotent Stem Cells (iPSCs) and in mouse HD neurons. Furthermore, HD mice treated with pridopidine show improvement in multiple behavioral and motor functions. 


Patients will be treated with pridopidine, administered orally in the form of two capsules, twice daily. The study will evaluate its effect on functional capacity, as well as on motor and behavioral features in participants with early-stage HD. 

study sites

PROOF-HD will take place in U.S., Canada and Europe. The study will take place at approximately 60 study centers in North America and in the EU and it will enroll 480 participants. Read More 

treatment period

The double-blind treatment period will last 78 weeks.

The study will consist of a screening period, a double-blind treatment period (Main study) and an Open-label extension (OLE).

inclusion criteria 

Eligible participants should meet the following criteria:

  • Male or female, 25 years of age and older, capable of giving informed consent.
  • Have a diagnosis of HD based on clinical features.
  • Have confirmed presence of CAG repeats of 36 or greater in the huntingtin gene.
  • Must have adult-onset HD with onset of signs and symptoms at, or later than 18 years of age
  • Stable heath conditions within 12 weeks before baseline.

Learn More 

Click here to read the FAQ on the Prilenia website