A Study to Evaluate the Efficacy, Safety and Immunogenicity of a Vaccine Designed to Protect Against Infection With Shigella Sonnei in Healthy Adults

The original study protocol has been amended due to requests from the FDA, requests from the
funder of the study, Bill & Melinda Gates Foundation (BMGF), and to further align the
protocol to other GSK studies and to the challenge model established at the Cincinnati
Children's Hospital Medical Centre.

Inclusion Criteria:

- Subjects who, in the opinion of the investigator, can and will comply with the
requirements of the protocol.

- Written informed consent obtained from the subject prior to performing any study
specific procedure.

- Individuals who, after the nature of the study has been explained to them, have shown
adequate comprehension of the study procedures and knowledge of study.

- A male or female between, and including, 18 and 50 years of age at the time of the
first vaccination.

- Healthy subjects as established by medical history and clinical examination before
entering into the study.

- Seronegative for human immunodeficiency virus (HIV), hepatitis B and C.

- Female subjects of non-childbearing potential may be enrolled in the study.

- Female subjects of childbearing potential may be enrolled in the study, if the
subject:

- Has practiced adequate contraception for 30 days prior to vaccination, and

- Has a negative pregnancy test on the day of vaccination, and

- Has agreed to continue adequate contraception during the entire study period.

Exclusion Criteria:

- Received an investigational or non-registered medicinal product within 30 days prior
to informed consent, or planned use during the study period.

- Any behavioral or cognitive impairment or psychiatric disease that, in the opinion of
the investigator, may interfere with the subject's ability to participate in the
study.

- History of any neurological disorders or seizures.

- Any other clinical condition that, in the opinion of the investigator, might pose
additional risk to the subject due to participation in the study.

- Human Leukocyte Antigen (HLA)-B27 positive test at screening and/or with history of
reactive arthritis.

- Clinical conditions representing a contraindication to intramuscular vaccination and
blood draws.

- Chronic administration of immunosuppressants or other immune-modifying drugs during
the period starting six months prior to the first vaccine/placebo dose. For
corticosteroids, this will mean prednisone ≥ 20 milligrams (mg)/day, or equivalent.
Inhaled except for doses > 800 µg/day and topical steroids are allowed.

- Administration of long-acting immune-modifying drugs at any time during the study
period. Subjects may be on chronic or as needed medications if, in the opinion of the
site principal investigator or appropriate sub-investigator, they pose no additional
risk to subject safety or assessment of reactogenicity and immunogenicity and do not
indicate a worsening of medical diagnosis or condition.

- Known bleeding diathesis or any condition that may be associated with a prolonged
bleeding time.

- Concurrently participating in another clinical study, at any time during the study
period, in which the subject has been or will be exposed to an investigational or a
non-investigational vaccine/product.

- History of having participated in a previous Shigella challenge study.

- Individuals who have a previously laboratory confirmed case of disease caused by S.
sonnei or serology positive for local anti S. sonnei LPS IgG Screening-ELISA at
screening.

- History of any serious chronic or progressive disease according to judgment of the
investigator.

- History of any malignancy or lymphoproliferative disorder.

- Known to be part of study personnel or being a close family member to the personnel
conducting this study.

- History of anaphylactic reaction or allergy to vaccine/placebo or challenge agent
components or any other allergies deemed by the investigator to increase the risk of
an AE if they were to participate in the study.

- Known allergy to ciprofloxacin or the other antibiotics used for treatment as deemed
by the investigator.

- Individuals receiving a course of antibiotics within a week of the challenge will be
ineligible to receive the challenge strain.

- History of gastric acid hyper-secretory disorders as assessed and judged by the
investigator or any other significant intestinal disorder.

- Any confirmed or suspected immunosuppressive or immunodeficient condition, based on
medical history and physical examination.

- Family history of congenital or hereditary immunodeficiency.

- History of any reaction or hypersensitivity likely to be exacerbated by any component
of the vaccine/placebo or challenge agent.

- Acute disease and/or fever at the time of enrolment.

- Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal
functional abnormality, as determined by physical examination or laboratory screening
tests. Chronic medical diagnoses or conditions should be stable for the last 60 days.
This includes no change in chronic prescription medication, dose, or frequency as a
result of deterioration of the chronic medical diagnosis or condition in the 60 days
prior to enrolment.

- A clinically significant sign or symptoms of acute illness, significant anomalies in
vital signs.

- Known to handle food as part of work related activities.

- Hepatomegaly, right upper quadrant abdominal pain or tenderness.

- Received immunoglobulins or any blood products within 180 days prior to informed
consent or planned administration during the study period.

- Pregnant or lactating female.

- Female planning to become pregnant or planning to discontinue contraceptive
precautions.

- Females with history of stillbirth, neonatal loss, or previous infant with anomaly,
except those who have had a planned termination of pregnancy, hysterectomy or
bilateral tubal ligation.

- History of chronic alcohol consumption and/or drug abuse. Chronic alcohol consumption
is defined as: a prolonged period of frequent, heavy alcohol use; the inability to
control drinking once it has begun; physical dependence manifested by withdrawal
symptoms when the individual stops using alcohol; tolerance, or the need to use more
and more alcohol to achieve the same effects; a variety of social and/or legal
problems arising from alcohol use.

- Known to have close household or professional contacts with people with
immunosuppressive condition.

- Documented HIV, hepatitis B and C positive subject.

- Any condition which, in the opinion of the investigator, may pose an increased and
unreasonable safety risk to the subject if they participated in the study.

- Subjects with a baseline neutrophil below 1800 cells/micro-liters (µL) lower limit of
normal range (LLN) OR with clinically significant abnormalities in other laboratory
values, according to local reference ranges and investigator judgment.

- Previous history of Benign Ethnic Neutropenia, or drug related Neutropenia.

- Concomitant treatment with neutropenic agents.