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.
This multicentre clinical trial will include 561 participants, allocated evenly across 3 groups (187 per group). Participants are assigned to one of three groups according to their prior PrEP regimen, provided their last dose was given at least 5 years prior to enrollment. • Group 1: 21IM regimen, (N = 187): received PrEP 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). • Group 2: 2²ID regimen (N = 187): received PrEP 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). • Group 3: 1²ID regimen (N = 187): received PrEP at least 5 years ago through 2 x 0,1 mL ID injections on Day 0 All subjects will receive 1 x 1,0 mL IM injection of purified chick-embryo cell-culture rabies vaccine as sPEP (booster) at least five years after primary vaccination (PrEP). Neutralizing antibody titers against rabies virus will be measured using the Rapid Fluorescent Focus Inhibition Test (RFFIT) on Day 0 (before administration of sPEP) and on Days 7 and 14 after sPEP vaccination. A titre of ≥ 0.5 IU/mL is defined as adequate (WHO standard).
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
561
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.
Clinical Trial Site Insitute of Tropical Medicine
Antwerp, Belgium
Cliniques Universitaires de Saint Luc
Brussels, Belgium
Centrum voor vaccinologie (CEVAC)
Ghent, Belgium
UZ Brussel
Jette, Belgium
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.
Time frame: 13 months - from First Patient In (FPI) to Last Patient Out (LPO)
RFFIT levels ≥ 0.5 IU/mL Day 14
To estimate per arm the proportion of participant with adequate immune response on Day 14 after the booster. RFFIT levels ≥ 0.5 IU/mL is the WHO standard for adequate immune response.
Time frame: 14 days following booster vaccination
FFIT levels ≥ 0.5 IU/mL on the day of the booster (Day 0).
To estimate per arm the proportion of participant with RFFIT levels ≥ 0.5 IU/mL on the day of the booster (Day 0). RFFIT levels ≥ 0.5 IU/mL is the WHO standard for adequate immune response.
Time frame: Day 0 - on day of booster vaccination
RFFIT levels ≥ 3.0 IU/mL on Day 7 after the booster
To estimate per arm the proportion of participant with RFFIT levels ≥ 3.0 IU/mL on Day 7 after the booster. A titre ≥ 3.0 IU/ml is considered to be a proxy for good/robust protection.
Time frame: Day 7 - following booster vaccination
RFFIT levels ≥ 3.0 IU/mL on Day 14 after the booster.
To estimate per arm the proportion of participants with RFFIT levels ≥ 3.0 IU/mL on Day 14 after the booster. A titre ≥ 3.0 IU/ml is considered to be a proxy for good/robust protection.
Time frame: Day 14 after the booster vaccination
Clinical Trial Unit Clinical Trial Unit Insitute of Tropical Medicine Antwerp, MsC
CONTACT
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Centre Hospitalier Universitaire de Liège
Liège, Belgium
Military Hospital Queen Astrid
Neder-Over-Heembeek, Belgium
RFFIT levels ≥ 10 IU/mL on Day 7 after the booster.
To estimate per arm the proportion of participants with RFFIT levels ≥ 10 IU/mL on Day 7 after the booster. A titre ≥ 10 IU/ml is considered to be a proxy for long-lasting immunity.
Time frame: Day 14 following the booster vaccination
RFFIT levels ≥ 10 IU/mL on Day 14 after the booster.
To estimate per arm the proportion of participants with RFFIT levels ≥ 10 IU/mL on Day 14 after the booster. A titre ≥ 10 IU/ml is considered to be a proxy for long-lasting immunity.
Time frame: Day 14 following the booster vaccination.
Safety objectives
Safety objectives 1. To estimate the proportion of solicited AEs (local reactions and general symptoms) occurring within 7 days after the sPEP vaccination session. 2. To estimate the proportion of unsolicited AEs occurring within 7 days after the sPEP vaccination session. 3. To estimate the proportion of Severe Adverse Events (SAE) occurring throughout the study period after sPEP vaccination session.
Time frame: 1. & 2. Day 7 following the booster vaccination. 3. 13 months - entire study duration FPI to LPO