The entire drug development program for this molecule was sold to another company.

This is a phase 3, open-label, multiple-center, randomized cross-over study to assess the safety and efficacy of [123I]NAV5001 SPECT imaging in aiding in the differentiaion of parkinsonian syndromes from non-parkinsonian tremor.

Inclusion Criteria:

• Subject has provided written informed consent before the initiation of any study related procedures and continues to give willing consent for participation
• Age ≥ 40 years
• Have had upper extremity tremor for < 3 years duration, regardless of presumed diagnosis or etiology
• Have a UPDRS part III score upon entry of ≤ 16

Exclusion Criteria:

• Any clinically significant or unstable physical or psychological illness based on medical history or physical examination at screening, as determined by the investigator
• Structural brain abnormality affecting the entire brain (e.g., normal pressure hydrocephalus) or the striatum (e.g., local tumor or stroke)
• Any clinically significant abnormal laboratory results obtained at screening and as determined by the investigator
• Any clinically significant abnormal electrocardiogram (ECG) results obtained at screening and as determined by the investigator
• Any history of drug, narcotic, or alcohol abuse within 2 years before the date of informed consent, as defined by the Diagnostic and Statistical Manual of the American Psychiatric Association, Fourth Edition, revised (DSM-IV-TR [American Psychiatric Association, 1994])
• Positive urine drug screen for opiates, cocaine, or amphetamines at screening
• Positive pregnancy test before imaging
• Participation in an investigational drug or device clinical trial within 30 days before the date of informed consent
• Previous scan with any DAT imaging agent (e.g. [123I]NAV5001, Altropane, DaTscan, DOPASCAN)
• Any exposure to radiopharmaceuticals within 30 days before the date of informed consent
• Breast-feeding
• Inability to lie supine for 1 hour
• Any thyroid disease other than adequately treated hypothyroidism
• Known sensitivity or allergy to iodine or iodine containing products
• Treatment within the 30 days before the date of imaging with amoxapine, amphetamine, benztropine, bupropion, buspirone, cocaine, mazindol, methamphetamine, methylphenidate, norephedrine, phentermine, phenylpropanolamine, selegiline, and sertraline, paroxetine, or citalopram.