A Randomized Double-Blind Placebo-Controlled Multiple Dose Study to Assess Efficacy Safety Tolerability and Pharmacokinetics of ABBV-8E12 in Progressive Supranuclear Palsy

Inclusion Criteria
Must be able to understand the nature of the study and has had the opportunity to have any questions answered
Meets the criteria for possible or probable PSP
Presence of PSP symptoms for less than 5 years
Able to walk 5 steps with minimal assistance
Has an identified, reliable, study partner, who has frequent contact with the subject and who can accompany the subject to study visits to provide information as to the subject's functional abilities
Exclusion Criteria
Pregnant or breastfeeding
Weighing less than 44 kg (97 lbs) at screening
MMSE score less than 15 at screening, or cognitive impairment that in the investigator's opinion would preclude collection of outcome measures
Any contraindication or inability to tolerate brain MRIs
During enrollment of Cohort 1, any contraindication or inability to tolerate lumbar punctures
Resides at a skilled nursing or dementia care facility, or admission to such a facility is planned during the study period
Evidence of any neurological disorder that could explain signs of PSP
Evidence of any clinically significant neurological disorder other than PSP
History of or currently has schizophrenia, schizoaffective disorder, or bipolar disorder
In the opinion of the investigator, the subject has any clinically significant uncontrolled psychiatric illness
Significant illness or infection requiring medical intervention in the past 30 days
Positive test result for hepatitis B surface antigen or hepatitis C virus antibody, or a known history of Human Immunodeficiency Virus infection
Has a history of evidence or a malignancy within the 2 years prior to the screening visit
Has myocardial infarction, advanced chronic heart failure, unstable angina, stroke, transient ischemic attack (TIA), clinically significant conduction abnormalities, or required intervention for any of these conditions within 1 year of screening
Any clinically significant hematological, autoimmune, endocrine, cardiovascular, neoplastic, renal, gastrointestinal, or other disorder that, in the Investigator's opinion, could interfere with the subject's participation in the study, place the subject at increased risk, or confound interpretation of any study results
Has a planned major surgical procedure scheduled during the period when the subject would be participating in this study
History of serious adverse reaction to ABBV-8E12 or other monoclonal antibodies or biologics
Has received an investigational product within a time period equal to 5 half-lives, if known, or within 6 weeks (for small molecules) or 6 months (for monoclonal antibodies or other biologics) prior to study drug administration
Has any history of prior receipt of active immunotherapy directed against tau
Current enrollment in another interventional clinical study involving a therapeutic agent