Safety and Immunogenicity of an Inactivated West Nile Virus Vaccine in Healthy Adults

NCT06745921 | Active Not Recruiting Phase 1 FDA Drug

• 2 other identifiers: 24-00085UM1AI148684-04
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

A randomized, placebo controlled, double-blind (within dosing group), sequential dose escalation study. This phase 1 trial addresses the urgent need for a vaccine to prevent disease resulting from infection with West Nile virus (WNV), a virus that is primarily spread to people by the bite of an infected mosquito. The purpose of this Phase 1 trial is to evaluate the safety and immunogenicity of the HydroVax-001B WNV vaccine in healthy adult volunteers. The study Population will consist of healthy male and non-pregnant, non-breastfeeding female adults, 18 to 49 years of age, inclusive. Potential participants with a history of prior flavivirus infection or receipt of any flavivirus vaccine or monoclonal antibody, and those who likely had a prior flavivirus infection based on exposure history will be ineligible for the study. Participants will be randomized to receive HydroVax-001B WNV vaccine or placebo in a 12:3 ratio within a dosage group. Participants will be sequentially enrolled into two dosage groups. The primary objective is to assess the safety and reactogenicity of 4 mcg versus 10 mcg dose of the HydroVax-001B WNV vaccine administered intramuscularly (IM) on Days 1, 29 and 181.

Conditions

West Nile Viral Infection

Keywords

Healthy Adults; HydroVax-001B WNV; Immunogenicity; Safety; Vaccine; West Nile Virus

Outcome Measures

Primary Outcomes (13)

• Frequency of any unsolicited adverse events (AEs)

  Day 1 through Day 29

• Frequency of related Grade 3 laboratory toxicities

  Day 1 through Day 15

• Frequency of related serious adverse events (SAE) overall and in each dose group through the end of the study

  Frequency is the number of discontinuous events

  Day 1 through study completion, approximately 13 months

• Frequency of solicited local adverse events (AEs)

  Day 1 through Day 8

• Frequency of solicited systemic adverse events (AEs)

  Day 1 through Day 8

• Incidence of any unsolicited adverse events (AEs)

  Day 1 through Day 29

• Incidence of related Grade 3 laboratory toxicities

  Day 1 through Day 15

• Incidence of related serious adverse events (SAE) overall and in each dose group through the end of the study

  Incidence is the number of participants with an event

  Day 1 through study completion, approximately 13 months

• Incidence of solicited local adverse events (AEs)

  Day 1 through Day 8

• Incidence of solicited systemic adverse events (AEs)

  Day 1 through Day 8

• Severity of any unsolicited adverse events (AEs)

  Day 1 through Day 29

• Severity of solicited local adverse events (AEs)

  Day 1 through Day 8

• Severity of solicited systemic adverse events (AEs)

  Day 1 through Day 8

Secondary Outcomes (2)

• Percentage of participants seroconverting

  Day 1 through Day 29

• West Nile Virus (WNV)-specific focus reduction neutralizing test (FRNT50) geometric mean titer (GMT)

  Day 15 through Day 181

Study Arms (4)

Group 1A

EXPERIMENTAL

A single, low dose, of 4 mcg of HydroVax-001B West Nile Virus (WNV) vaccine administered intramuscularly once on Day 1, Day 29, and Day 181. N=12

Biological: HydroVax-001B WNV; Other: Sodium Chloride, 0.9%

Group 1B

EXPERIMENTAL

A single, high dose, of 10 mcg of HydroVax-001B West Nile Virus (WNV)vaccine administered intramuscularly once on Day 1, Day 29, and Day 181. N=12

Biological: HydroVax-001B WNV; Other: Sodium Chloride, 0.9%

Group 2A

PLACEBO COMPARATOR

A 0.5 mL dose of placebo, consisting of 0.9 % of NaCl, administered intramuscularly once on Day 1, Day 29, Day 181. N=3

Other: Placebo

Group 2B

PLACEBO COMPARATOR

A 0.5 mL dose of placebo, consisting of 0.9 % of NaCl, administered intramuscularly once on Day 1, Day 29, Day 181. N=3

Other: Placebo

Interventions

HydroVax-001B WNV BIOLOGICAL

A vaccine to West Nile Virus (WNV) that is prepared by propagating naturally attenuated Kunjin strain of WNV on well characterized low-passage Vero cells. The vaccine contains 10 mcg of inactivated purified whole virion WNV formulated in a volume of 0.5 mL/dose with 0.10% aluminum hydroxide, 10% D-sorbitol, 0.001% Polysorbate 80 (Tween80) in 10 mM phosphate-buffer with 350 mM NaCl.

Group 1A; Group 1B

Placebo OTHER

Placebo

Group 2A; Group 2B

Sodium Chloride, 0.9% OTHER

0.9% Sodium Chloride Injection

Group 1A; Group 1B

Eligibility Criteria

• Age: 18 Years - 49 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Provides written informed consent prior to initiation of any study procedures.
• Is able to understand and agrees to comply with planned study procedures including being available for all study visits.
• Agrees to the collection of venous blood per protocol.
• Is a male or non-pregnant, non-lactating female 18 to 49 years of age, inclusive at time of enrollment.

You may not qualify if:

• Oral temperature is less than 100.4 degrees Fahrenheit at screening.
• Pulse is 51 to 100 beats per minute, inclusive at screening.
• Systolic blood pressure is 90 to 140 mmHg, inclusive at screening.
• Diastolic blood pressure is 55 to 90 mmHg, inclusive at screening.
• Screening labs must be within acceptable parameters at screening.\*
• Tests for human immunodeficiency virus (HIV) antigens/antibodies, hepatitis B virus (HBV) surface antigen, and hepatitis C virus (HCV) antibodies must be negative at screening.
• Females who are of childbearing potential\* must agree not to become pregnant during trial.
• \*Not of childbearing potential includes post-menopausal females (defined as no menses for at least 12 consecutive months without an alternative medical cause for amenorrhea), or surgically sterile females with documented per volunteer report history of hysterectomy, bilateral oophorectomy, tubal ligation/salpingectomy, or Essure(R) placement and at least 3 months have passed since sterilization procedure.
• Females of childbearing potential must agree to use an acceptable contraception method\* from at least 30 days before the first study vaccination and for the duration of the trial.
• \*Acceptable forms of contraception include monogamous relationship with a vasectomized male partner who has been vasectomized for 90 days or more prior to enrollment, use of intrauterine devices, birth control pills, hormonal birth control products that are injectable, implantable (subdermal), transdermal or insertable (vaginal ring), barrier methods with spermicide. Females of childbearing potential who practice abstinence (defined as no heterosexual vaginal-penile intercourse) and agree to practice abstinence consistently for the duration of the study or those who have exclusively non-male sexual relations do not need to use contraception.
• Females of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test prior to each study vaccination.
• Has body mass index (BMI) 18.5 kg/m\^2 to 34.9 kg/m\^2, inclusive.
• Has an acute illness\* (with or without fever \>/= 38 degrees Celsius \[100.4 degrees Fahrenheit\]) as determined by the PI or appropriate sub-investigator within 72 hours prior to study product administration.
• \*Participants who are afebrile (if applicable) and have either no symptoms or only minor residual symptoms in the 72 hours prior to study product administration can be enrolled if, in the opinion of the site PI or appropriate sub-investigator, the residual symptoms will not interfere with the ability to assess safety parameters as required by the protocol.
• Has medical disease or condition that, in the opinion of the site PI or appropriate sub-investigator, is a contraindication to study participation.\*

Sponsors & Collaborators

• National Institute of Allergy and Infectious Diseases (NIAID): lead

Study Sites (1)

Saint Louis University Center for Vaccine Development

St Louis, Missouri, 63104-1015, United States

Location

MeSH Terms

Interventions

Sodium Chloride

Intervention Hierarchy (Ancestors)

Chlorides; Hydrochloric Acid; Chlorine Compounds; Inorganic Chemicals; Sodium Compounds

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Masking Details: Syringe will be masked
• Purpose: PREVENTION
• Intervention Model: SEQUENTIAL
• Sponsor Type: NIH
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 12, 2024
• First Posted: December 20, 2024
• Study Start: February 24, 2025
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): November 1, 2027
• Last Updated: May 1, 2026

Record last verified: 2025-05-13

Locations

US (1)