Phase I, Randomized, Double-blinded, Placebo-Controlled Dose De-escalation Study to Evaluate Safety and Immunogenicity of Alum Adjuvanted Zika Virus Purified Inactivated Vaccine (ZPIV) in Adults in a Flavivirus Endemic Area

This study is randomized, double-blinded, placebo-controlled, Phase 1, dose de-escalation study to evaluate the safety, reactogenicity, and immunogenicity of Alum Adjuvanted Zika Virus Purified Inactivated Vaccine (ZPIV) administered to healthy male and non-pregnant female adult subjects. This study will enroll 90 healthy male and non-pregnant female subjects between the ages of 21 and 49 and will be conducted at Ponce Medical School Foundation, Inc.-CAIMED in Ponce, Puerto Rico. The duration of each subject's participation is approximately 26 months from recruitment through the last study visit. The entire study is expected to take approximately 49 months to complete. Two dose levels will be evaluated. Each subject will receive either placebo or 5 mcg (Group 1) or 2.5 mcg (Group 2) of ZPIV administered by intramuscular (IM) injection on Days 1 and 29. Solicited local and systemic reactogenicity data will be collected from all subjects through Day 8 after each vaccination. All subjects will be monitored for occurrence of unsolicited adverse events until 28 days after the second vaccination. The study will consist of a screening period of up to 28 days, a vaccination period in which subjects will receive a prime dose of vaccine on Day 1 followed by a boost on Day 29, and a follow-up period of 24 months post boost vaccination. Primary objectives are: 1) Assess the safety and reactogenicity of a homologous prime boost regimen of ZPIV given at two different dose levels. 2) Compare the safety and reactogenicity of ZPIV after each vaccination, between dosage groups, and by pre-vaccination flavivirus immune status.

This study is a single-center, randomized, double-blinded, placebo-controlled, Phase 1, dose de-escalation study to evaluate the safety, reactogenicity, and immunogenicity of a purified inactivated, alum-adjuvanted ZIKV vaccine (ZPIV) administered in a homologous prime-boost regimen to healthy male and non-pregnant female adult subjects living in a flavivirus-endemic area. This study will enroll 90 subjects between the ages of 21 and 49 and will be conducted at Ponce Medical School Foundation, Inc.-CAIMED in Ponce, Puerto Rico. The entire duration of each subject's participation is approximately 26 months including recruitment and collection of data on the safety and reactogenicity of the study vaccine and collection of samples for the assessment of immunogenicity. This study is expected to take approximately 49 months to complete. Two dose levels will be evaluated. Each subject will receive either placebo or 5 mcg (Group 1) or 2.5 mcg (Group 2) of ZPIV administered by intramuscular (IM) injection on Days 1 and 29. The study will consist of a screening period of up to 28 days, a vaccination period in which subjects will receive a prime dose of vaccine on Day 1 followed by a homologous boost on Day 29, and a follow-up period of 24 months post boost vaccination. The study will begin with enrollment of 2 sentinel subjects in Group 1 who will receive 5 mcg ZPIV open label. One sentinel subject will be vaccinated, followed for one day for safety and reactogenicity, and if no halting rules are met per determination of the PI and co-PI, then the second sentinel subject will receive 5 mcg ZPIV open-label. Both sentinels will be followed for safety through Day 8 and if no predefined halting rules are met and no safety concerns are identified, then enrollment of the Group 1 non-sentinel subjects will proceed in double-blind fashion. The same procedure will be used for administration of the boost vaccination to the Group 1 sentinels: 1 sentinel (can be either) will receive 5 mcg ZPIV open-label, be followed for one day for safety and reactogenicity, and if no halting rules are met, then the 2nd sentinel will receive the boost vaccine. Both sentinels will be followed until Day 8 after 2nd vaccination for safety and reactogenicity and if no halting rules are met, then boost vaccination of the Group 1 non-sentinel subjects can proceed. Enrollment of the 2.5 mcg ZPIV group (Group 2) can begin after or at the same time non-sentinel subjects in Group 1 receive the 1st dose of vaccine. As of December 18, 2017, the majority of non-sentinel subjects in Group 1 have already received the 1st dose and have been followed until Day 8 for safety and reactogenicity, and no halting rules have been met or safety concerns identified. As this is a dose de-escalation study, concurrent enrollment of some remaining non-sentinel subjects in Groups 1 is permitted after enrollment of Group 2 subjects has begun; also, no sentinel subjects will be used in Group 2. All subjects in Group 2 will receive study product or placebo in double-blind fashion. The original study design planned to enroll 40 ZPIV recipients and 5 placebo recipients in each Group. However, due a natural disaster (hurricane Maria), 11 subjects enrolled in Group 1 had loss of samples at key timepoints. To rebalance the number of evaluable subjects between Groups, Group 1 enrollment will be increased by 5 subjects and Group 2 enrollment will be decreased by 5 subjects, for a total enrollment of 50 subjects in Group 1 and 40 in Group 2. Treatment assignments for both groups will be assigned according to the originally planned 8:1 ratio of ZPIV: placebo. Without compromising the blind of the study, we can anticipate approximately 35 evaluable ZPIV recipients and approximately 5 evaluable placebo recipients in each group. All subjects will receive a homologous boost of ZPIV or placebo 28 days post-prime if no halting rules precluding second vaccination are met (Section 9). All subjects will be monitored for occurrence of unsolicited AEs until 28 days after the second vaccination SAEs, AESIs, and history of new medical conditions with onset after the first vaccination will be collected for the duration of the study. Blood for evaluation of antibodies to ZIKV by ELISA and neutralizing antibody assays will be collected at Visit 00, prior to each vaccination, and at multiple timepoints afterward. Primary objectives are: 1) Assess the safety and reactogenicity of a homologous prime boost regimen of ZPIV given at two different dose levels in a dose de-escalation format in healthy adult subjects who live in Puerto Rico, a flavivirus endemic area. 2) Compare the safety and reactogenicity profile of ZPIV after each vaccination, between dosage groups, and by pre-vaccination flavivirus immune status. Secondary Objectives are: 1) Assess the humoral immune response to a homologous prime-boost regimen of ZPIV after each dose of vaccine as determined by kinetics of the immune responses, seroconversion rates, and Geometric Mean Titers (GMT) overall, and compare results between dosage groups and by pre-vaccination flavivirus immune status. 2) Assess the durability of the humoral immune response to ZPIV at 6, 12, 18, and 24 months after the second vaccine administration overall, and compare results between dosage groups and by pre-vaccination flavivirus immune status.

Eligibility Criteria:
Inclusion Criteria:

1. Must be a male or non-pregnant, non-breastfeeding female between the age of 21 and 49 years, inclusive at the time of screening and enrollment.
2. Must be willing and able to read, sign and date the informed consent document before study related procedures are performed.
3. Must be willing and able to comply with study requirements and available for follow-up visits for the entire study.
4. Must have a means to be contacted by telephone.
5. Must have a body mass index (BMI) \> /= 18.1 and \< 35.0 kg/m2.
6. Must have acceptable\* screening laboratory findings within 28 days before enrollment.

   * Acceptable clinical laboratory parameters include:

     * Hemoglobin: women: \> /= 11.5 g/dL; men \> /= 13.5 g/dL
     * Hemotocrit: women: \> /= 34.5%; men \> /= 40.5%
     * White blood cell count: \> /= 3.500 cells/mm3 but \< /= 10,800 cells/mm3
     * Platelets: \> /= 150,000 but \< /= 450,000 per mm3
     * Urine dipstick (clean urine sample): protein \< 1+, glucose negative
     * Serum creatinine \< /= 1 x institutional upper limit of normal (ULN)
     * Blood urea nitrogen (BUN) \< 25
     * Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) \< 1.25 x institutional ULN
     * Total bilirubin \< 1.25 x institutional ULN
   * Note: If laboratory screening tests are out of acceptable range, repeat of screening tests is permitted once, provided there is an alternative explanation for the out of range value.
7. Must be in good health based on the investigator's clinical judgment when considering findings from past medical history, medication use, vital signs, and an abbreviated physical examination.

   Note 1: Good health is defined by the absence of any medical condition described in the exclusion criteria in a subject with a normal abbreviated physical exam and vital signs. If the subject has a preexisting condition not listed in exclusion criteria, it cannot meet any of the following criteria: 1) first diagnosed in last 3 months; 2) worsening in terms of clinical outcome in last 6 months; or 3) involves need for medication that may pose a risk to subject's safety or impede assessment of adverse events or immunogenicity if they participate in study.

   Note 2: An abbreviated physical exam differs from a complete exam in that it does not include a genitourinary and rectal exam.

   Note 3: Vital signs must be normal by protocol toxicity grading scale or determined to be normal-variant by investigator. In the event of an abnormal heart rate or blood pressure due to physiological variation or activity, the subject may rest for 10 minutes in a quiet room, and then blood pressure and/or heart rate may be re-measured. Repeated vital signs may be used to determine eligibility.
8. Women of childbearing potential\* must have a negative serum pregnancy test at screening and a negative urine pregnancy test immediately prior to each vaccination.

   Note: All female subjects are considered of childbearing potential unless postmenopausal or surgically sterilized and \> /= 3 months have passed since sterilization procedure. Postmenopausal is defined as amenorrhea for \> /= 12 months without an alternative medical cause. Permanent female sterilization procedures include tubal ligation, bilateral salpingectomy, hysterectomy, bilateral oophorectomy, or successful Essure placement.
9. Women of childbearing potential must use an acceptable method of contraception\* from one month (30 days) prior to the first vaccination until the end of the study.

   \*Acceptable methods of contraception include the following:
   * Use highly effective contraceptive methods, defined by \< 1% failure rate per year independent of user adherence, including long-acting reversible contraception (LARC): progestin-releasing subdermal implants and intrauterine devices (IUD), OR
   * Use effective contraceptive methods, defined by 5-9% failure rate with typical use and \< 1% failure rate with consistent and correct use, including: prescription oral contraceptives, contraceptive injections, combined pill, progestin-only pill, hormone-releasing transdermal patch or vaginal ring, and depot medroxyprogesterone acetate injection (Depo-Provera), OR
   * Male sex partners must have had a vasectomy \> /= 3 months prior to first vaccination, OR
   * Practice abstinence defined as refraining from heterosexual intercourse from 30 days before first vaccination until the end of the study.
10. Female subjects must agree to not donate eggs (ova, oocytes) from the start of screening period until the end of the study.
11. Subjects must provide concurrent consent at the time of enrollment and 1st vaccination to future use of stored blood samples to measure immunity to ZIKV.

Exclusion Criteria:

1. Has plans to become pregnant during the course of the study, or is currently pregnant or breastfeeding.
2. Plans to receive a licensed flavivirus vaccine or participate in another flavivirus vaccine trial during the study.
3. Has positive serology for HIV 1/2, Hepatitis C virus, or Hepatitis B surface antigen.
4. Has known or suspected congenital or acquired immunodeficiency, or recent history or current use of immunosuppressive therapy\* \*Anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term (at least 2 weeks within the previous 3 months) systemic corticosteroids therapy (at a dose of at least 0.5 mg/kg/day). Intranasal or topical prednisone (or equivalent) is allowed.
5. Had organ and/or stem cell transplantation whether or not on chronic immunosuppressive therapy.
6. Has history of malignancy other than squamous cell or basal cell skin cancer, unless there has been surgical excision that is considered to have achieved cure\*.

   \*Subjects with a history of skin cancer must not be vaccinated at the previous tumor site.
7. Has history of chronic or acute severe neurologic condition\*.

   \*Including history of Guillain-Barre syndrome, seizure disorder or epilepsy, Bell's palsy, meningitis, or disease with any focal neurologic deficits.
8. Has diabetes mellitus type 1 or type 2, including cases controlled with diet alone.

   \*Note: history of isolated gestational diabetes is not an exclusion criterion.
9. Has history of thyroidectomy, or thyroid disease requiring medication during the last 12 months.
10. Has major psychiatric illness during last 12 months that in the investigator's opinion would preclude participation.
11. Has history of other chronic disease or condition\*.

    \*Includes the conditions and diagnoses defined as AESI in section 9, as well as autoimmune disease, hypercholesterolemia, chronic hepatitis or cirrhosis, chronic pulmonary disease, chronic renal disease, and chronic cardiac disease including hypertension even if medically controlled

    - Vital signs must be normal by protocol toxicity grading scale or determined to be normal-variant by investigator. In the event of an abnormal heart rate or blood pressure due to physiological variation or activity, the subject may rest for 10 minutes in a quiet room, and then blood pressure and/or heart rate may be re-measured. Repeated vital signs may be used to determine eligibility.
12. Has current or past history of substance abuse that in the investigator's opinion would preclude participation.
13. Has tattoos, scars, or other marks on both deltoid areas that would, in the opinion of the investigator, interfere with assessment of the vaccination site.
14. Has a history of chronic urticaria (recurrent hives).
15. Has known allergy or history of anaphylaxis or other serious reaction to a vaccine or vaccine component\*.

    \*Including aluminum hydroxide (alum) or aminoglycosides (e.g., neomycin and streptomycin).
16. Had major surgery (per the investigator's judgment) in the month prior to screening or plans to have major surgery during the study.
17. Received blood products or immunoglobulin in the 3 months prior to screening or planned use during the course of the study.
18. Donated a unit of blood within 8 weeks before Day 1 or plans to donate blood during the course of the study.
19. Received live attenuated vaccine from 30 days before Day 1 or plans to receive a live attenuated vaccine from Day 1 until 30 days after the last vaccination.
20. Received killed or inactivated vaccine from 14 days before Day 1 or plans to receive a killed or inactivated vaccine from Day 1 until 14 days after the last vaccination.
21. Received experimental therapeutic agents within 3 months prior to the first study vaccination or plans to receive any experimental therapeutic agents during the course of the study.
22. Is currently participating or plans to participate in another clinical study involving an investigational product, blood drawing, or an invasive procedure listed below.

    \*An invasive procedure requiring administration of anesthetics or intravenous dyes or removal of tissue would be excluded. This includes endoscopy, bronchoscopy, or administration of IV contrast.
23. Has an acute illness or temperature \> /= 38.0ºC on Day 1 or Day 29\* or within 2 days prior to vaccination.

    \*Subjects with fever or an acute illness on the day of vaccination or in the 2 days prior to vaccination may be re-assessed and enrolled if healthy or only minor residual symptoms remain within 2 days of Day 1 or Day 29.
24. Is a study site employee\* or staff paid entirely or partially by the OCRR contract or subcontract for the trial, or staff who are supervised by the PI or Sub-Investigators.

    \*Including the Principal Investigator, sub-Investigators listed in Form FDA 1572 or Investigator of Record Form
25. In the investigator's opinion, the subject cannot communicate reliably, is unlikely to adhere to the study requirements, or has a condition that would limit their ability to complete the study.