Edible Hepatitis B Vaccine Therapy in Healthy Participants Who Have Undergone Previous Vaccination

OBJECTIVES: I. To evaluate the safety, tolerability, and immunogenicity of orally delivered
HBsAg that is formulated as an expressed protein in transgenic potato tubers (HBV-EPV) at
different doses and schedules. OUTLINE: Patients are randomized to 1 of 4 treatment arms.
ARM I: Participants consume placebo HBV-EPV on days 0, 14, 28, and 56. ARM II:
Participants consume HBV-EPV expressing HBsAg on days 0 and 28 and placebo HBV-EPV on days
14 and 56. ARM III: Participants consume HBV-EPV expressing HBsAg on days 0, 28, and 56
and placebo HBV-EPV on day 14. ARM IV: Participants consume HBV-EPV expressing HBsAg on
days 0, 14, 28, and 56. After completion of study treatment, patients are followed up at
days 70, 84, 98, and 114.

Inclusion Criteria:

- All Roswell Park Cancer Institute (RPCI) staff, faculty, and students, who are in
good health

- Participants confirmation of history of primary immunization series with recombinant
hepatitis B (HB) vaccine (last dose at least one year prior to screening anti-HBs
level assessment)

- Current anti-HBs levels less than or equal to 115 mIU/mL

- Major organ functions within acceptable medical limits as determined in routine
clinical laboratory screening tests

- Expected availability for the duration of the study period

- If female, then documentation that the subject is not pregnant by an acceptable
laboratory test and that the subject is using an adequate birth control method to
prevent pregnancy for at least 3 months following the last immunization in the study

- Human immunodeficiency virus (HIV) antibody negative

- Ability to provide written informed consent

- Supervisor approval

Exclusion Criteria:

- Known history of allergy or hypersensitivity to potato, potato components or potato
products

- Known history of allergy to hepatitis B vaccine in any form or to components of
hepatitis B vaccine

- Pregnancy or breast feeding

- Current anti-HBS levels greater than 115 mIU/mL

- Known immunodeficiency, cancer, or use of immunosuppressive medication including
cancer chemotherapy and systemic steroids (excluding intermittent use of topical
steroids)

- Participation in another investigational study within 30 days of enrollment in this
study

- Known and currently active gastrointestinal disease including any of the following:
peptic ulcer disease, gastroesophageal reflux, inflammatory bowel disease,
diverticulitis, or pancreatitis

- Use of prescription medication or over the counter H2 blockers or proton pump
inhibitors (PPIs) for any of the above diseases regularly and within 1 month of
enrollment

- Diagnosis of insulin-dependent diabetes or multiple sclerosis

- Significant laboratory abnormality which suggests dysfunction of hematological,
renal, or hepatic systems

- Known history of hepatitis B infection in the past

- Temporary exclusion for mild upper respiratory illness, gastrointestinal illness, or
other febrile episode that is expected and documented to resolve