Donor-Alloantigen-Reactive Regulatory T Cell (darTregs) in Liver Transplantation

After liver transplantation, immunosuppressants must be taken every day to prevent the body
from injuring the transplanted liver by a process called rejection. People who take these
drugs may experience side effects.

Studies show that some of body's cells, called T regulatory cells (Tregs), may play a part in
accepting the transplanted liver. The investigators are learning about whether scientists can
take Tregs from the blood of a liver transplant recipient and teach them to protect the
transplanted liver from rejection. In the laboratory, the recipient Tregs are exposed to
cells from the liver donor. Research data suggests that giving these "donor reactive" Tregs
back to the transplant recipient might allow a liver transplant recipient to take lower doses
of immunosuppressants, or perhaps to stop them altogether, without rejecting the liver.

Inclusion Criteria:

- Subjects who meet all of the following criteria are eligible for enrollment as study
participants:

- Able to understand and provide informed consent

- End-stage liver disease and listed for primary solitary liver transplant

- Have a calculated Model for End Stage Liver Disease (MELD) score ≤ 25 at the time
of study entry/consent

- Female and male subjects with reproductive potential must agree to use effective
methods of birth control for the duration of the study.

- If history of Hepatitis C Virus (HCV), have completed or are in current treatment
for HCV AND have no detectable HCV RNA.

- Subjects with HCC meeting Milan criteria.

Exclusion Criteria:

- Below are exclusion criteria to be assessed at study enrollment, prior to Stage 1
study procedures. Subjects who meet any of these criteria are not eligible for Stage 1
study procedures. Note that subjects in Cohort 1a or 1b will NOT undergo leukapheresis
regardless of eligibility.

- End stage liver disease secondary to autoimmune etiology (autoimmune hepatitis,
primary biliary cirrhosis, or primary sclerosing cholangitis)

- History of less than 5 years remission of malignancy, except for 1) HCC or 2)
history of adequately treated in-situ cervical carcinoma, or adequately treated
basal or squamous cell carcinoma of the skin.

- History of previous organ, tissue or cell transplant

- Serologic evidence of human immunodeficiency (HIV) 1 or -2 infection

- Epstein-Barr Virus (EBV) or cytomegalovirus (CMV) sero-negativity (EBV or CMV
naïve candidates)

- Chronic use of systemic glucocorticoids or other Immunosuppression (IS), or
biologic immunomodulators

- Chronic condition requiring anti-coagulation after liver transplantation

- Any chronic illness or prior treatment which, in the opinion of the investigator,
precludes study participation

- Participation in any other studies that involved investigational drugs or
regimens in the preceding year

- Received any vaccination within 28 days prior to leukapheresis or blood
collection for Treg manufacture

- Hemoglobin <9.0 g/dL within 10 days prior to screening

- Neutrophils <1,500/μL within 10 days prior to screening

- Platelets <40,000/μL within 10 days prior to screening

- Thymoglobulin Exclusion Criteria B (Stage 2):

- Below are exclusion criteria to be assessed prior to administration of
Thymoglobulin®. Subjects who meet any of these criteria should not receive
Thymoglobulin®:

- Calculated Model for End Stage Liver Disease (MELD) score >25 at the time of
deceased donor liver transplant

- Last alpha-fetoprotein (AFP) obtained prior to liver transplantation >400
μg/L for candidates with Hepatocellular Carcinoma (HCC)

- Unacceptable Peripheral Blood Mononuclear Cells (PBMC) product for
participants enrolled in Cohorts 2, 3, or 4 per the UCSF The Human Islet and
Cellular Transplant Facility (HICTF) manufacturing specifications

- Absence of donor spleen for any participants

- Human leukocyte antigen (HLA)-DR (DR is one of class II antigens) matched to
donor at both loci

- Subject is < 21 or >70 years of age at the time of transplantation

- Located in the intensive care unit 72 hours after transplantation

- Hemoglobin <8.0 g/dL

- Absolute neutrophil count <1,200/μL

- Platelets <40,000/μL

- Positive pregnancy test for females of child bearing potential

- Unexpected histopathology on back table liver biopsy that contraindicates
the initiation of Treg supportive IS regimen.

- Development of a condition requiring chronic anti-coagulation.

- Hypersensitivity to rabbit proteins or any excipient in Thymoglobulin®.

- Detectable HCV RNA or less than six months after end of treatment for HCV at
the time of transplantation (i.e., does not meet criteria for SVR).

- Below are exclusion criteria to be assessed prior to conversion to Everolimus
(EVR)-based IS regimen. (Assessed at day 30-44 after transplantation for
continuation in the trial) All subjects regardless of eligibility for EVR
conversion, with any of the following will not receive darTregs and will move
into safety follow up:

- Explanted liver with evidence of increased risk of recurrent cancer risk
(hepatocellular (HCC) tumor burden exceeding the Milan criteria; presence of
vascular invasion; cholangiocarcinoma morphology)

- Insufficient depletion of recipient T cells, defined as a nadir CD3 count
≥50 cells μ/L (50 cells /mcL) or total lymphocyte count ≥ 0.1x 109/L if CD3
count is unavailable

- Development of a condition requiring chronic anti-coagulation.

- Clinical evidence of biliary obstruction

- Alanine Aminotransferase (ALT) >2.0 x upper limit of normal (ULN)

- Inability to taper off corticosteroids by 44 days (+/- 2 days) after
transplant

- Detectable circulating HCV RNA.

Everolimus Conversion Criteria C2 (assessed prior to conversion to EVR based IS regimen;
EVR cannot be initiated prior to 30 days after liver transplantation). Subjects with any of
the following will remain on TAC-based IS regimen.

- Evidence of hepatic artery stenosis or thrombosis by Doppler examination or
angiography within 7 days prior to conversion

- Urine protein/creatinine ratio >1.0 within 7 days prior to conversion

- Calculated GFR less than 30 ml/min per MDRD4 (Modification of Diet in Renal Disease
Study) equation within 7 days prior to conversion

- Physical examination documentation of abnormal wound healing or uncontrolled wound
infection

- Hemoglobin <8.0 g/dL within 7 days prior to conversion

- Absolute neutrophil count <1,200/μL within 7 days prior to conversion

- Platelets <50,000/μL within 7 days prior to conversion

*Below are exclusion criteria to be assessed prior to darTreg infusion for subjects in
Cohorts 2, 3, and 4 only. Subjects in Cohort 2, 3, or 4 who meet any of these criteria
should not receive a darTreg-infusion:

- Inability or unwillingness of participant to give additional written informed consent

- Unacceptable darTreg product

- Detectible circulating Epstein-Barr Virus (EBV) or cytomegalovirus (CMV) DNA within 10
days prior to darTreg infusion

- Detectible Hepatitis B Virus (HBV) DNA within 10 days prior to darTreg infusion

- Detectable circulating HCV RNA within 10 days prior to darTreg infusion.

- Alanine Aminotransferase (ALT) >1.5x upper limit of normal within 10 days of darTreg
infusion

- Most recent, but not greater than 10 days prior to darTreg infusion,12 hour TAC trough
levels of > 8 μg/L for all subjects

- Most recent, but not greater than 10 days prior to darTreg infusion,12 hour EVR trough
levels of < 5 μg/L for subjects on EVR

- For subjects on EVR-based IS, received Mycophenolate Mofetil (MMF) within 10 days
prior to darTreg infusion

- Evidence of acute rejection or chronic rejection according to Banff criteria on
protocol allograft biopsy based on local assessment

- Received any vaccination within 14 days prior to darTreg infusion

- Positive pregnancy test for females of child bearing potential

- Inability or unwillingness of participant to comply with study protocol or procedures.

- Calculated glomerular filtration rate (eGFR) less than 40 ml/min per MDRD4 equation
within 10 days prior to infusion.