Investigating efficacy and safety of adjunctive therapy in Parkinson’s Disease patients


Parkinson’s Disease involves the loss of brain cells that produce dopamine, a messenger that sends information to the parts of the brain that control movement and coordination. Lower than normal levels of dopamine in the brain causes the symptoms of Parkinson’s, including muscle stiffness, resting tremor (uncontrollable shaking), and slowing of movements. Parkinson’s patients may have “on” periods where they are able to control their muscle movement, and “off” times when controlling these movements is harder.

Levodopa is a medication used to help treat Parkinson’s by increasing dopamine levels in the brain. We are looking for participants who have these “on” and “off” periods, and who are on Levodopa and at least one other medication. We are looking at whether adding tozadenant, a drug that hasn’t been approved by the U.S. FDA, will help improve Parkinson’s symptoms.

Keywords: parkinsons adjunctive therapy

Study Sites

Keck School of Medicine of USC, 1520 San Pablo Street, Suite 3000 90033

  • Men & Women
Age icon

What's involved?

Study length
  • 24 weeks of double blind treatment

  • 52 weeks of open label treatment

Number of visits
  • 14 office visits lasting from 3 to 7 hours

  • None

  • Blood & urine sample

  • $50 debit card per clinic visit

Medical cost coverage
  • None

Why participate?

Medical advances are impossible without volunteers.


Must have

  • Confirmed diagnosis of Parkinson’s disease for at least 3 years.
  • Be taking at least four doses of a medication containing levodopa and one other anti-Parkinson’s medication.
  • Must be on an anti-Parkinson’s medication regimen and stable for at least 4 weeks before screening.
  • Women of childbearing age must be using contraception 4 weeks prior to starting study drug.
  • Men with potentially fertile partner must be willing to use acceptable contraception or have undergone vasectomy.

Can't have

  • BMI greater than 35.
  • Pacemaker or implantable cardioverter defibrillator.
  • Known diagnosis of malignant melanoma.
  • Pregnant or planning to become pregnant during the study.
  • Grade 2 hypertension.
  • History of neurosurgical intervention for PD i.e. deep brain stimulation.
  • Previous participation in any study with tozadenant, or study of an IMP or medical device in last 3 months or 5 half-lives of IMP.

Study Team

Rvrumkrptruqnlcoxqmt Collaborate with the PI

For questions about this study, contact:

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