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Lancet Infect Dis. 2015 Oct;15(10):1156-1166. doi: 10.1016/S1473-3099(15)00154-1. Epub 2015 Aug 4.

The effect of dose on the safety and immunogenicity of the VSV Ebola candidate vaccine: a randomised double-blind, placebo-controlled phase 1/2 trial.

Author information

1
Infection Control Programme, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland; Division of Infectious Diseases, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
2
Division of Infectious Diseases, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
3
Virology Laboratory, Geneva University Hospitals, Geneva, Switzerland.
4
Division of Clinical Epidemiology, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
5
WHO Collaborating Centre for Vaccinology, Faculty of Medicine, Geneva, Switzerland.
6
Centre for Clinical Research, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
7
Philipps University Marburg, Institute for Virology, Marburg, Germany.
8
Division of Rheumatology, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
9
Department of Molecular Virology and Department of Translational Sciences, US Army Medical Research, Institute for Infectious Diseases (USAMRIID), Frederick, MD, USA.
10
Division of Dermatology, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland.
11
World Health Organization, Geneva, Switzerland.
12
Division of Infectious Diseases, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland; Virology Laboratory, Geneva University Hospitals, Geneva, Switzerland.
13
WHO Collaborating Centre for Vaccinology, Faculty of Medicine, Geneva, Switzerland; Center for Vaccinology, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland. Electronic address: claire-anne.siegrist@unige.ch.

Abstract

BACKGROUND:

Safe and effective vaccines against Ebola could prevent or control outbreaks. The safe use of replication-competent vaccines requires a careful dose-selection process. We report the first safety and immunogenicity results in volunteers receiving 3 × 10(5) plaque-forming units (pfu) of the recombinant vesicular stomatitis virus-based candidate vaccine expressing the Zaire Ebola virus glycoprotein (rVSV-ZEBOV; low-dose vaccinees) compared with 59 volunteers who had received 1 ×10(7) pfu (n=35) or 5 × 10(7) pfu (n=16) of rVSV-ZEBOV (high-dose vaccinees) or placebo (n=8) before a safety-driven study hold.

METHODS:

The Geneva rVSV-ZEBOV study, an investigator-initiated phase 1/2, dose-finding, placebo-controlled, double-blind trial conducted at the University Hospitals of Geneva, Switzerland, enrolled non-pregnant, immunocompetent, and otherwise healthy adults aged 18-65 years. Participants from the low-dose group with no plans to deploy to Ebola-aff5cted regions (non-deployable) were randomised 9:1 in a double-blind fashion using randomly permuted blocks of varying sizes to a single injection of 3 × 10(5) pfu or placebo, whereas deployable participants received single-injection 3 × 10(5) pfu open-label. Primary safety and immunogenicity outcomes were the incidence of adverse events within 14 days of vaccination and day-28 antibody titres, respectively, analysed by intention to treat. After viral oligoarthritis was observed in 11 of the first 51 vaccinees (22%) receiving 10(7) or 5 × 10(7) pfu, 56 participants were given a lower dose (3 × 10(5) pfu, n=51) or placebo (n=5) to assess the effect of dose reduction on safety and immunogenicity. This trial is ongoing with a follow-up period of 12 months; all reported results are from interim databases. This study is registered with ClinicalTrials.gov, number NCT02287480.

FINDINGS:

Between Jan 5 and Jan 26, 2015, 43 non-deployable participants received low-dose rVSV-ZEBOV (3 × 10(5) pfu) or placebo in a double-blind fashion, whereas 13 deployable participants received 3 × 10(5) pfu open-label. Altogether, in the low-dose group, 51 participants received rVSV-ZEBOV and five received placebo. No serious adverse events occurred. At 3 × 10(5) pfu, early-onset reactogenicity remained frequent (45 [88%] of 51 compared with 50 [98%] of 51 high dose and two [15%] of 13 placebo recipients), but mild. Objective fever was present in one (2%) of 51 low-dose versus 13 (25%) of 51 high-dose vaccinees receiving at least 1 ×10(7) pfu (p<0·0001). Subjective fever (p<0·0001), myalgia (p=0·036), and chills (p=0·026) were significantly reduced and their time of onset delayed, reflecting significantly lower viraemia (p<0·0001) and blood monocyte-activation patterns (p=0·0233). Although seropositivity rates remained similarly high (48 [94%] of 51), day-28 EBOV-glycoprotein-binding and neutralising antibody titres were lower in low-dose versus high-dose vaccinees (geometric mean titres 344·5 [95% CI 229·7-516·4] vs 1064·2 [757·6-1495·1]; p<0·0001; and 35·1 [24·7-50·7] vs 127·0 [86·0-187·6]; p<0·0001, respectively). Furthermore, oligoarthritis again occurred on day 10 (median; IQR 9-14) in 13 (25%) of 51 low-dose vaccinees, with maculopapular, vesicular dermatitis, or both in seven (54%) of 13; arthritis was associated with increasing age in low-dose but not high-dose vaccinees. Two vaccinees presented with purpura of the lower legs; histological findings indicated cutaneous vasculitis. The presence of rVSV in synovial fluid and skin lesions confirmed causality.

INTERPRETATION:

Reducing the dose of rVSV-ZEBOV improved its early tolerability but lowered antibody responses and did not prevent vaccine-induced arthritis, dermatitis, or vasculitis. Like its efficacy, the safety of rVSV-ZEBOV requires further definition in the target populations of Africa.

FUNDING:

Wellcome Trust through WHO.

PMID:
26248510
PMCID:
PMC6624136
DOI:
10.1016/S1473-3099(15)00154-1
[Indexed for MEDLINE]
Free PMC Article

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