Boostability Assessment of Three Rabies Pre-Exposure Regimens in Healthy Volunteers 5 Years Following Priming.

NCT07455318 | Not Yet Recruiting Phase 3

• 2 other identifiers: BAZOOKA_2212025-524765-24-00
• Study Type: interventional
• Target: 561
• Locations: 1 country
• Sites: 6

Brief Summary

A multicentre, open label trial in healthy volunteers to assess the boostability of three different rabies pre-exposure prophylaxis regimens (2 x 1IM regimen, 2 x 2 ID regimen, 1 x 2 ID regimen) when administering a single-dose, intramuscular vaccination as simulated post-exposure prophylaxis at least five years following priming.

Conditions

Rabies (Healthy Volunteers)

Keywords

Rabies; Vaccination regimens; rabies pre-exposure prophylaxis; boostability; prophylaxis; vaccination

Outcome Measures

Primary Outcomes (1)

• Primary: boostability

  To investigate whether the boostability of a (A) two-visit IM, (B) two-visit ID and (C) one-visit ID Pre-exposure Prophylaxis (PrEP) regimen is non-inferior to a theoretical 99% boostability when a single-dose IM simulated Post Exposure Prophylaxis (sPEP) is administered at least 5 years after the PrEP regimen. Primary Endpoint: Proportion of participants that have an adequate immune response (Rapid Fluorescent Focus Inhibition Test (RFFIT) level, WHO standard) on Day 7 after the booster.

  13 months - from First Patient In (FPI) to Last Patient Out (LPO)

Secondary Outcomes (7)

• RFFIT levels ≥ 0.5 IU/mL Day 14

  14 days following booster vaccination

• FFIT levels ≥ 0.5 IU/mL on the day of the booster (Day 0).

  Day 0 - on day of booster vaccination

• RFFIT levels ≥ 3.0 IU/mL on Day 7 after the booster

  Day 7 - following booster vaccination

• RFFIT levels ≥ 3.0 IU/mL on Day 14 after the booster.

  Day 14 after the booster vaccination

• RFFIT levels ≥ 10 IU/mL on Day 7 after the booster.

  Day 14 following the booster vaccination

Study Arms (3)

Group 1: 2 x 1IM regimen, (N = 187):

EXPERIMENTAL

Healthy volunteers that received Pre-Exposure Prohphylaxis (PrEP) (a rabies vaccination) at least 5 years ago through 1 x 1,0 mL IM injection (Day 0 and Day 7), with a 7-day interval between visits (interval of 5 to 56 days is allowed).

Biological: Booster vaccination

Group 2: 2²ID regimen (N = 187):

EXPERIMENTAL

Received PrEP vaccination (Pre-Exposure prophylaxis usinga rabies vaccine) at least 5 years ago through 2 x 0,1 mL ID injections (Day 0 and Day 7) with a 7-day interval between visits (interval of 5 to 56 days is allowed).

Biological: Booster vaccination

Group 3: 1²ID regimen (N = 187)

EXPERIMENTAL

received PrEP (Pre-Exposure prophylaxis using a rabies vaccine) at least 5 years ago through 2 x 0,1 mL ID injections on Day 0

Biological: Booster vaccination

Interventions

Booster vaccination BIOLOGICAL

To investigate whether the boostability of a (A) two-visit IM, (B) two-visit ID and (C) one-visit ID pre-exposure vaccination regimen is non-inferior to a theoretical 99% boostability by administering a single-dose IM booster to simulate exposure to rabies at least 5 years after the pre-exposure regimens regimen.

Group 1: 2 x 1IM regimen, (N = 187):; Group 2: 2²ID regimen (N = 187):; Group 3: 1²ID regimen (N = 187)

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Willingness to provide written informed consent
• Having received PrEP with a 21IM, 2²ID or 1²ID regimen at least 5 years before starting the study. For 21IM and 2²ID interval of 5 days to 56 days between the 2 visits is allowed.

You may not qualify if:

• Known allergy to one of the components of the vaccine.
• Subjects, who received immunomodulating therapy within the last 3 months (12 weeks).
• Note: See Section 6.3 for detailed guidance on immunomodulating therapies.
• Planned vaccination with any inactivated vaccine within 2 weeks before or after vaccination in the study or with any live attenuated vaccine within 1 month before or after each vaccination in the study.
• Ongoing pregnancy or active child wish at the time of booster vaccination (D0).
• Previous rabies (s)PEP
• Inability or unwillingness to comply with study procedures, including protocol-defined visits, assessments, or interventions.

Sponsors & Collaborators

• Institute of Tropical Medicine, Belgium: lead

Study Sites (6)

Clinical Trial Site Insitute of Tropical Medicine

Antwerp, 2000, Belgium

Location

Cliniques Universitaires de Saint Luc

Brussels, 1200, Belgium

Location

Centrum voor vaccinologie (CEVAC)

Ghent, 9000, Belgium

Location

UZ Brussel

Jette, 1090, Belgium

Location

Centre Hospitalier Universitaire de Liège

Liège, 4000, Belgium

Location

Military Hospital Queen Astrid

Neder-Over-Heembeek, 1120, Belgium

Location

MeSH Terms

Conditions

Rabies

Interventions

Immunization, Secondary

Condition Hierarchy (Ancestors)

Rhabdoviridae Infections; Mononegavirales Infections; RNA Virus Infections; Virus Diseases; Infections

Intervention Hierarchy (Ancestors)

Immunization; Immunotherapy; Immunomodulation; Biological Therapy; Therapeutics; Immunologic Techniques; Investigative Techniques

Central Study Contacts

Thomas Hendrickx, MsC

CONTACT

000000000000000000000000000000; thendrickx@itg.be

Clinical Trial Unit Clinical Trial Unit Insitute of Tropical Medicine Antwerp, MsC

CONTACT

000000000000000000000000000000; ctu@itg.be

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 23, 2026
• First Posted: March 6, 2026
• Study Start: May 15, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): June 1, 2027
• Last Updated: March 6, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

BE (6)