Safety, Tolerability, and Efficacy of Two Different Oral Doses of NP031112 Versus Placebo in the Treatment of Patients With Mild-to-Moderate Progressive Supranuclear Palsy

1. Men and women with diagnosis of possible or probable PSP according to clinical criteria of National Institute of Neurologic Diseases and Stroke - the Society for PSP (Appendix 1).

2. Age of 40 to 85 years (patients over 85 years could be included after previous assessment by Investigator and approved by sponsor).

3. Brain magnetic resonance imaging (MRI) study within 24 months before Baseline visit excluding other potential causes of parkinsonism, especially cerebrovascular lesions and space occupying lesions.

4. Mild-to-moderate stage of disease severity according to score of 1 to 4 in Golbe Staging System.(Appendix 2)

5. Female patients must be surgically sterilized; at least 1 year postmenopausal (confirmed by follicle-stimulating hormone [FSH] >20 international units [IUs]); using adequate birth control (implants, injectables, combined oral contraceptives, intrauterine contraceptive device, total sexual abstinence during the study or vasectomised partner). Male patients must be willing to use barrier contraception (condom) during the study and for 6 months after last treatment administration.

In European arms of study female patients must be without childbearing potential.

6. Caregiver (or dedicated nurse) living in same household or interacting with patient for >4 hours every day able to assure correct preparation and administration of study drug.

7. Patients living at home or in retirement home not requiring continuous nursing care.

8. General health status acceptable for participation in 64-week clinical trial.

9. Ability to swallow 100 mL of water suspension.

10. Any concomitant medication for PSP must be well-tolerated and unchanged for at least 1 month prior to Baseline visit and its dose and regimen should be maintained during study if there are no clinical reasons to modify it.

11. Occupational, physical, respiratory, or speech therapy is allowed but it must be stable for at least 1 month prior to screening.

12. Pharmacological treatment of any other chronic condition must be stable and well-tolerated for at least 1 month prior to screening. Analgesics, occasional per request nonsteroidal anti-inflammatory agents, and treatments for transient or emergent conditions are allowed.

13. Signed informed consent by patient and permitted prior to initiation of any study-specific procedure

1. Failure to perform screening or baseline examinations.

2. Hospitalization or change of chronic concomitant medication 1 month prior to or during screening period (apart from pre-planned hospitalization for a condition, which did not deteriorate since 1 month prior to screening period).

3. Clinical, laboratory or neuroimaging findings consistent with:

4. A current Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) diagnosis of active major depression, schizophrenia or bipolar disorder.

5. Clinically significant, advanced or unstable disease that may interfere with primary or secondary variable evaluations, may bias clinical or mental assessment or put patient at special risk, such as:

6. Disability that may prevent the patient from completing all study requirements (e.g., blindness, deafness, and severe language difficulty).

7. Chronic daily drug intake of:

8. Suspected or known history of drug abuse or excessive alcohol intake*

9. Suspected or known allergy to any components of study treatments.

10. Enrollment in another investigational drug study within 3 months before Baseline visit.

11. Any condition, which in the opinion of Investigator makes patient unsuitable for inclusion or likely to be non-compliant.