Safety, Immunogenicity, and Dose Ranging Study of Inactivated Zika Virus Vaccine in Healthy Participants

A Phase 1, Randomized, Observer-Blind, Placebo-Controlled, Safety, Immunogenicity, and Dose Ranging Study of Purified Inactivated Zika Virus Vaccine (PIZV) Candidate in Flavivirus Naïve and Primed Healthy Adults Aged 18 to 49 Years

The purpose of this study is to describe the safety, tolerability and immunogenicity of two doses of purified inactivated Zika virus vaccine (PIZV) given 28 days apart. Three different vaccine doses containing different protein concentrations (2, 5 or 10 microgram [mcg]) each, will be given as 2 dose schedule to flavivirus naive and primed healthy adults. Participants will be followed for 7 days post each dose for tolerability and up to 6 months post dose 2 for safety. Immunogenicity assessment will be performed at 28 days post each dose and 6 months post dose 2. In addition, the selected dose group and control group will be followed till 24 months post dose 2 for safety and persistence of immunity.

The vaccine being tested in this study is called PIZV or TAK-426 adjuvanted with aluminum hydroxide. The Zika virus vaccine is being tested to provide safety and immunogenicity data to enable the vaccine to be further developed clinically.

The study will enroll approximately 240 participants. Participants will be randomly assigned (by chance, like flipping a coin) to one of the four groups-which will remain undisclosed to the study observer:

• Placebo
• PIZV: 2 microgram (mcg) Low Dose
• PIZV: 5 mcg Medium Dose
• PIZV: 10 mcg High Dose

All participants will be administered either placebo or PIZV by intramuscular (IM) injection into the middle third of the deltoid muscle, preferably in the non-dominant arm on Days 1 (Visit 1) and 29 (Visit 4).

This multi-center trial will be conducted in the United States and Puerto Rico. The overall time to participate in this study is up to 25 months. Participants will make multiple visits to the clinic on Days 1, 8, 29, 36, 57, 211, 393 and will be contacted by telephone on Day 133 (Visit 7) and Day 575 (Visit 9) and also visit the clinic on Day 757 (Visit 11) depending on the study arm, for a final follow-up assessment.

Inclusion Criteria:

1. Participants who are in good health at the time of entry into the trial as determined by medical history, physical examination (including vital signs) and eligibility screening tests (hematology, biochemistry and urinalysis) and clinical judgment of the investigator. Vital signs must be within normal limits (ie, below Grade 1 as specified in the Food and Drug Administration [FDA] Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers). Screening tests must be within normal limits or not be above Grade 1 as defined in the FDA Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers.
2. Participants who can comply with trial procedures and are available for the duration of follow-up.
3. All female participants must be willing to undergo serum beta human chorionic gonadotropin (B-hCG) pregnancy test and must test negative by urine pregnancy test prior to each study vaccination.

Exclusion Criteria:

1. Participants and participants' partners with confirmed Zika virus (ZIKV) infection by self-report.

2. Traveling to flavivirus endemic countries or flavivirus endemic regions of the United States (US) or US territories*, within 4 weeks prior to screening or planned travel through to Visit 6 (applicable only to participants to be enrolled into the flavivirus naïve cohort).

   a. Centers for Disease Control and Prevention (CDC) website define the information about the flavivirus endemic countries and US regions and territories.

3. Known hypersensitivity or allergy to any of the vaccine candidate components (including excipients of the investigational vaccine or placebo).

4. Has any history of progressive or severe neurologic disorder, seizure disorder or neuro-inflammatory disease (example, Guillain-Barré syndrome).

5. Known or suspected impairment/alteration of immune function, including:

   • Chronic use of oral steroids (equivalent to 20 milligram per day [mg/day] prednisone greater than or equal to [>=] 12 weeks / >= 2 milligram per kilogram [mg/kg] body weight / day prednisone >= 2 weeks) within 60 days prior to Day 1 (use of inhaled, intranasal, or topical corticosteroids is allowed).
   • Receipt of parenteral steroids (equivalent to 20 mg/day prednisone >= 12 weeks / >= 2 mg/kg body weight / day prednisone >= 2 weeks) within 60 days prior to Day 1.
   • Receipt of immunostimulants within 60 days prior to Day 1.
   • Receipt of parenteral, epidural or intra-articular immunoglobulin preparation, blood products, and/or plasma derived products within 3 months prior to Day 1 or planned during the full length of the trial. In addition, participants must be advised not to donate blood during the study period.
   • Known Human Immunodeficiency Virus (HIV) infection or HIV-related disease.
   • Genetic immunodeficiency.

6. Has known current or chronic hepatitis B and/or hepatitis C infections.

7. Has abnormalities of spleen or thymic function.

8. Has a known bleeding diathesis, or any condition that may be associated with a prolonged bleeding time.

9. Individuals participating in any clinical trial with another investigational product, including ZIKV vaccine clinical trial within 30 days prior to first trial visit or intent to participate in another clinical trial at any time during the conduct of this trial.

10. Individuals who received any other vaccines within 14 days (for inactivated vaccines) or 28 days (for live vaccines) prior to enrollment in this trial or who are planning to receive any vaccine within 28 days of investigational vaccine/placebo administration.

11. Female participants who are pregnant or breastfeeding, or are planning to become pregnant.

12. Any positive or indeterminate pregnancy test.

13. If female participant of childbearing potential, sexually active, and who has not used any of the "acceptable contraceptive methods" for at least 2 months prior to trial entry:

    • "Of childbearing potential" is defined as status post onset of menarche and not meeting any of the following conditions: menopausal for at least 2 years without any other alternative medical cause (as confirmed by a healthcare professional), status after bilateral tubal ligation for at least 1 year, status after bilateral oophorectomy, or status after hysterectomy.

    • Acceptable birth control methods are defined as one or more of the following:

      • Hormonal contraceptive (such as oral, injection, transdermal patch, implant, cervical ring).
      • Barrier (condom with spermicide or diaphragm with spermicide) each and every time during intercourse.
      • Intrauterine device.
      • Monogamous relationship with vasectomized partner. Partner must have been vasectomized for at least six months prior to the participants' trial entry.

14. If female participant of childbearing potential and sexually active, refusal to use an "acceptable contraceptive method" from trial entry through 2 months after the last dose of investigational vaccine/placebo. In addition female participants of childbearing potential must be advised not to donate ova during this period.

15. To avoid sexual transmission of ZIKV from natural exposure: Refusal to use latex condoms correctly and consistently by sexually active participants even if other contraceptive measures are used from signing the informed consent form (ICF) through the end of the trial. Male participants must be advised not to donate sperm during this period.