This study seeks to determine the safety and immunogenicity of a series of 3 primary
vaccinations and a booster vaccination of Recombinant ricin toxin A-chain 1-33/44-198 (rRTA
1-33/44-198) vaccine (RVEc) at 10 or 20 μg intradermally (ID). This study is evaluating if
RVEc will display an acceptable safety profile as determined by adverse event (AE) data and
if RVEc will elicit anti-ricin antibody titers and ricin toxin-neutralizing antibodies in
- Study participants must read and sign an approved informed consent.
- Study participants must be at least 18 years old at time of screening and no older
than 50 years old at time of first study vaccination.
- Participants must weigh at least 110 pounds at time of screening.
- Participants must be in good health as judged from medical history, physical
examination, electrocardiogram, chest x-ray, hematology, clinical chemistries,
urinalysis, hepatitis serology, and human immunodeficiency virus (HIV) antibody test
and must be medically cleared for participation by an investigator.
- Females of childbearing potential must have a negative pregnancy test on screening
and the morning of each vaccination prior to receipt of the vaccine and must agree to
use a highly effective method of birth control from screening through 3 months
following last study vaccination. A highly effective method of birth control is
defined as one with a failure rate of less than 1% per year. Acceptable birth control
methods that meet this criterion include hormonal implants and injectables, combined
oral contraceptives, intrauterine devices, female sterilization (tubal ligation),
sexual abstinence, or a vasectomized partner.
- Female participants must also agree not to breastfeed from screening through 3 months
following last study vaccination.
- Study participants must be willing to return for all follow-up visits.
- Study participants must agree to report any adverse events (AE) that may or may not
be associated with administration of the investigational product through the duration
of study participation.
- Study participants must agree to abstain from excessive exercise (more than the usual
routine) and excessive alcohol consumption (exceeds 2 drinks for males or exceeds 1
drink for females daily or binge drinking) for the duration of study participation.
- Acute or chronic medical conditions or immunodeficiency from a medical condition or
medical treatment, medications, or dietary supplements that, in the investigator's
opinion, would impair the subject's ability to respond to vaccination. Use of
corticosteroids, other than inhaled or topical corticosteroids or eye drops, will not
- Severe hypersensitivity to any vaccine.
- History of asthma, chronic obstructive pulmonary disease, or other current/residual
diseases of the lungs.
- Clinically significant abnormal laboratory tests. (Normal reference ranges are
determined by the local clinical laboratory.)
- Current smoker, to include use of electronic cigarettes.
- Any known allergies to sodium succinate, Polysorbate 20 (a detergent), Alhydrogel, or
- Receipt of any vaccine or investigational product within 30 days before or after
vaccination with RVEc (the only exception is the inactivated influenza vaccine that
can be received at least 30 days after RVEc Dose 3 or 4).
- Creatine phosphokinase levels that are consistently elevated more than 2 × normal.
- Previous vaccination with RVEc or any other ricin vaccine candidate by any route.