Young Plasma Transfusions for Progressive Supranuclear Palsy

This is a phase 1, multi-center, open-label study of the safety, tolerability,
pharmacodynamics, and preliminary efficacy of young (<30 years of age) healthy male donor
plasma transfusions in patients with PSP. Up to 10 subjects will receive once monthly 4-unit
transfusions of young healthy male donor plasma for 6 months.

If ≥3 subjects experience drug limiting toxicity (DLT), as defined in Section 7.19, the study
will be terminated. Any subject that experiences a DLT will be discontinued from further
treatment with the study drug.

An interim futility analysis will be performed after five subjects have completed 6 months of
study drug treatment. If the criteria listed in Section 9.3 of this protocol are met, an
additional 5 subjects will be enrolled in the trial. If not, the trial will be terminated.

Inclusion Criteria:

1. Meets National Institute of Neurological Disorders and Stroke - Society for
Progressive Supranuclear Palsy (NINDS-SPSP) probable or possible PSP criteria (Litvan
et al. 1996b), as modified for the AL-108-231 davunetide trial (Boxer et al. 2014);

2. Between 50 and 85 years of age (inclusive);

3. MRI at Screening is consistent with PSP (≤ 4 microhemorrhages and no large strokes or
severe white matter disease);

4. MMSE score at Screening is between 14 and 30 (inclusive);

5. Stable medications for 2 months prior to Screening, including Food and Drug
Administration- (FDA-) approved Alzheimer's disease (AD) medications and Parkinson's
disease medications;

6. Availability of a study partner who knows the subject well and is willing to accompany
the subject to all trial visits and to participate in questionnaires;

7. Agrees to 3 MRIs;

8. Agrees to 2 lumbar punctures for CSF examination;

9. Signed and dated written informed consent obtained from the subject and subject's
caregiver in accordance with local IRB regulations;

10. Males and all WCBP agree to abstain from sex or use an adequate method of
contraception for the duration of the study and for 30 days after the last dose of
study drug.

- Adequate contraceptive methods include those with a low failure rate, i.e., less
than 1% per year, when used consistently and correctly, such as complete
abstinence from sexual intercourse with a potentially fertile partner, and some
double barrier methods (condom with spermicide) in conjunction with use by the
partner of an intrauterine device (IUD), diaphragm with spermicide, oral
contraceptives, birth control patch or vaginal ring, oral, or injectable or
implanted contraceptives;

- For this study, a woman who has been surgically sterilized or who has been in a
state of amenorrhea for more than two years will be deemed not to be of
childbearing potential.

Exclusion Criteria:

1. Meets National Institute on Aging-Alzheimer's Association Workgroups criteria for
probable AD (McKhann et al. 2011);

2. Any medical condition other than PSP that could account for cognitive deficits (e.g.,
active seizure disorder, stroke, vascular dementia);

3. A prominent and sustained response to levodopa therapy;

4. History of significant cardiovascular, hematologic, renal, or hepatic disease (or
laboratory evidence thereof);

5. History of major psychiatric illness or untreated depression;

6. Neutrophil count <1,500/mm3, platelets <100,000/mm3, serum creatinine >1.5 x upper
limit of normal (ULN), total bilirubin >1.5 x ULN, alanine aminotransferase (ALT) >3 x
ULN, aspartate aminotransferase (AST) >3 x ULN, or INR >1.2 at Screening evaluations;

7. Evidence of any clinically significant findings on Screening or baseline evaluations
which, in the opinion of the Investigator would pose a safety risk or interfere with
appropriate interpretation of study data;

8. Current or recent history (within four weeks prior to Screening) of a clinically
significant bacterial, fungal, or mycobacterial infection;

9. Current clinically significant viral infection;

10. Major surgery within four weeks prior to Screening;

11. Any contraindication to or unable to tolerate lumbar puncture at Screening, including
use of anti-coagulant medications such as warfarin. Daily administration of 81 mg
aspirin will be allowed as long as the dose is stable for 30 days prior to Screening;

12. Any contraindication to monthly plasma transfusions, including but not limited to: a.
History of significant transfusion complications; b. Lack of a competent adult in the
home to summon medical assistance if needed; c. Lack of a telephone to contact
emergency personnel or lack of easy access for emergency vehicles; d. Compatible
plasma units not available; e. Prior intolerance to intravenous (IV) fluids; f. IgA
deficiency by history or laboratory evidence at Screening; g. Uremia or bleeding; h.
Any concurrent use of an anti-coagulant therapy. Daily administration of 81 mg aspirin
will be allowed as long as the dose is stable for 30 days prior to Screening.
Anti-platelet drugs are acceptable.

13. Treatment with another investigational drug or participation in another interventional
clinical trial within 3 months of Screening;

14. Treatment with any human blood product, including IV immunoglobulin, during the 6
months prior to Screening or during the trial;

15. Pregnant or lactating;

16. Positive pregnancy test at Screening or Baseline (Day 1);

17. Cancer within 5 years of Screening, except for non-metastatic skin cancer or
non-metastatic prostate cancer not expected to cause significant morbidity or
mortality within one year of Baseline.