Trial Outcomes & Findings for Flavivirus Cross-priming Potential of IMOJEV (NCT NCT03920111)

NCT ID: NCT03920111

Last Updated: 2025-01-31

Results Overview

Plasmablast percentage of total B cells at 7 days post vaccine Number of plasmablasts sorted by flow cytometry at 7 days post vaccine

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 19 participants
• Primary outcome timeframe: 1 week
• Results posted on: 2025-01-31

Participant Flow

There was difficult in recruiting naïve participants. Therefore the target was changed to 4-8. The total number of participants was not fixed, there was flexibility across the groups, up to a total of 22 participants. The protocol allowed participant replacement if the week 1 blood sample was not collected. This happened to one participant in group 3 who had already received the vaccine, then discontinued. therefore the total number enrolled in this group was 11.

Participant milestones

Measure	Group 1 - Any Status Up to 3-4 healthy adults. Participants will be replaced if they withdraw before the one week protocol blood sample. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 2 - FlaviPrime Naive Up to 4-8 healthy adults who have never travelled to a flavivirus endemic area and are negative in screening tests for flavivirus immunity. Participants will be replaced if they withdraw before the one week protocol blood sample. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 3 - Flavivirus Exposed Up to 8-10 healthy adults who have had JE vaccine and/or are previously flavivirus exposed, either through receiving yellow fever vaccine up to 5 years before the study, or from being diagnosed with a flavivirus illness (e.g. dengue or Zika). Participants will be replaced if they withdraw before the one week protocol blood sample.. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®
Overall Study STARTED	4	4	11
Overall Study COMPLETED	4	4	10
Overall Study NOT COMPLETED	0	0	1

Reasons for withdrawal

Measure	Group 1 - Any Status Up to 3-4 healthy adults. Participants will be replaced if they withdraw before the one week protocol blood sample. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 2 - FlaviPrime Naive Up to 4-8 healthy adults who have never travelled to a flavivirus endemic area and are negative in screening tests for flavivirus immunity. Participants will be replaced if they withdraw before the one week protocol blood sample. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 3 - Flavivirus Exposed Up to 8-10 healthy adults who have had JE vaccine and/or are previously flavivirus exposed, either through receiving yellow fever vaccine up to 5 years before the study, or from being diagnosed with a flavivirus illness (e.g. dengue or Zika). Participants will be replaced if they withdraw before the one week protocol blood sample.. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®
Overall Study suspected covid - unable to attend study visit	0	0	1

Baseline Characteristics

Flavivirus Cross-priming Potential of IMOJEV

Baseline characteristics by cohort

Measure	Group 1 - Any Status n=4 Participants Up to 3-4 healthy adults IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 2 - FlaviPrime Naive n=4 Participants Up to 6-8 healthy adults who have never travelled to a flavivirus endemic area and are negative in screening tests for flavivirus immunity. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 3 - Flavivirus Exposed n=11 Participants Up to 8-10 healthy adults who have had JE vaccine and/or are previously flavivirus exposed, either through receiving yellow fever vaccine up to 5 years before the study, or from being diagnosed with a flavivirus illness (e.g. dengue or Zika). IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Total n=19 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Age, Categorical Between 18 and 65 years	4 Participants n=5 Participants	4 Participants n=7 Participants	10 Participants n=5 Participants	18 Participants n=4 Participants
Age, Categorical >=65 years	0 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants	1 Participants n=4 Participants
Sex: Female, Male Female	3 Participants n=5 Participants	3 Participants n=7 Participants	5 Participants n=5 Participants	11 Participants n=4 Participants
Sex: Female, Male Male	1 Participants n=5 Participants	1 Participants n=7 Participants	6 Participants n=5 Participants	8 Participants n=4 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Asian	1 Participants n=5 Participants	0 Participants n=7 Participants	3 Participants n=5 Participants	4 Participants n=4 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants	1 Participants n=4 Participants
Race (NIH/OMB) White	3 Participants n=5 Participants	4 Participants n=7 Participants	7 Participants n=5 Participants	14 Participants n=4 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Region of Enrollment United Kingdom	4 participants n=5 Participants	4 participants n=7 Participants	11 participants n=5 Participants	19 participants n=4 Participants

PRIMARY outcome

Timeframe: 1 week

Population: Percentage of total B cells that are plasmablasts.

Plasmablast percentage of total B cells at 7 days post vaccine Number of plasmablasts sorted by flow cytometry at 7 days post vaccine

Outcome measures

Measure	Group 2 - FlaviPrime Naive n=4 Participants Up to 6-8 healthy adults who have never travelled to a flavivirus endemic area and are negative in screening tests for flavivirus immunity. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 3 - Flavivirus Exposed n=10 Participants Up to 8-10 healthy adults who have had JE vaccine and/or are previously flavivirus exposed, either through receiving yellow fever vaccine up to 5 years before the study, or from being diagnosed with a flavivirus illness (e.g. dengue or Zika). IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 1 - Any Status n=4 Participants Up to 3-4 healthy adults IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®
Primary: Plasmablast Percentage of Total B Cells at 7 Days Post Vaccine	1.96 percent plasmablasts of B cells Interval 0.98 to 2.65	1.69 percent plasmablasts of B cells Interval 0.018 to 3.35	1.36 percent plasmablasts of B cells Interval 1.14 to 2.14

PRIMARY outcome

Timeframe: two months

Population: geometric mean +/- 95% confidence interval

Neutralising antibody titre, measured by 50% of viral plaque reduction at one and two months post vaccine

Outcome measures

Measure	Group 2 - FlaviPrime Naive n=4 Participants Up to 6-8 healthy adults who have never travelled to a flavivirus endemic area and are negative in screening tests for flavivirus immunity. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 3 - Flavivirus Exposed n=10 Participants Up to 8-10 healthy adults who have had JE vaccine and/or are previously flavivirus exposed, either through receiving yellow fever vaccine up to 5 years before the study, or from being diagnosed with a flavivirus illness (e.g. dengue or Zika). IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 1 - Any Status n=4 Participants Up to 3-4 healthy adults IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®
Primary: Neutralisation Titre, Measured by 50% of Viral Plaque Reduction at One and Two Months Post Vaccine Antibody titre at 4 weeks post vaccine	283 50% neutralisation titre Interval 72.7 to 1106.0	932 50% neutralisation titre Interval 568.0 to 1528.0	882 50% neutralisation titre Interval 302.0 to 2574.0
Primary: Neutralisation Titre, Measured by 50% of Viral Plaque Reduction at One and Two Months Post Vaccine Antibody titre at 8 weeks post vaccine	232 50% neutralisation titre Interval 85.4 to 629.0	931 50% neutralisation titre Interval 554.0 to 1566.0	705 50% neutralisation titre Interval 284.0 to 1746.0

SECONDARY outcome

Timeframe: one month

Number of adverse events occurring in all participants in one month post vaccine

Outcome measures

Measure	Group 2 - FlaviPrime Naive n=4 Participants Up to 6-8 healthy adults who have never travelled to a flavivirus endemic area and are negative in screening tests for flavivirus immunity. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 3 - Flavivirus Exposed n=11 Participants Up to 8-10 healthy adults who have had JE vaccine and/or are previously flavivirus exposed, either through receiving yellow fever vaccine up to 5 years before the study, or from being diagnosed with a flavivirus illness (e.g. dengue or Zika). IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 1 - Any Status n=4 Participants Up to 3-4 healthy adults IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®
Secondary: Number of Adverse Events Occurring in All Participants in One Month Post Vaccine	0 Number of adverse events	9 Number of adverse events	1 Number of adverse events

Adverse Events

Group 1 - Any Status

Serious events: 0 serious events

Other events: 1 other events

Deaths: 0 deaths

Group 2 - FlaviPrime Naive

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Group 3 - Flavivirus Exposed

Serious events: 0 serious events

Other events: 6 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Measure	Group 1 - Any Status n=4 participants at risk Up to 3-4 healthy adults IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 2 - FlaviPrime Naive n=4 participants at risk Up to 4-8 healthy adults who have never travelled to a flavivirus endemic area and are negative in screening tests for flavivirus immunity. IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®	Group 3 - Flavivirus Exposed n=11 participants at risk Up to 8-10 healthy adults who have had JE vaccine and/or are previously flavivirus exposed, either through receiving yellow fever vaccine up to 5 years before the study, or from being diagnosed with a flavivirus illness (e.g. dengue or Zika). IMOJEV: live attenuated Japanese encephalitis (JE) vaccine IMOJEV®
Respiratory, thoracic and mediastinal disorders Rhinorrhoea	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	9.1% 1/11 • Number of events 1 • one month post vaccination Number of adverse events
Respiratory, thoracic and mediastinal disorders Cough	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	18.2% 2/11 • Number of events 2 • one month post vaccination Number of adverse events
Blood and lymphatic system disorders Neutropenia	25.0% 1/4 • Number of events 1 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/11 • one month post vaccination Number of adverse events
Gastrointestinal disorders Diarrhoea	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	9.1% 1/11 • Number of events 1 • one month post vaccination Number of adverse events
Infections and infestations Tooth Infection	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	9.1% 1/11 • Number of events 1 • one month post vaccination Number of adverse events
Nervous system disorders Parasthesia	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	9.1% 1/11 • Number of events 1 • one month post vaccination Number of adverse events
Musculoskeletal and connective tissue disorders Pulled Right Hamstring	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	9.1% 1/11 • Number of events 1 • one month post vaccination Number of adverse events
Vascular disorders Right Leg Superficial Thrombophlebitis	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	9.1% 1/11 • Number of events 1 • one month post vaccination Number of adverse events
General disorders Malaise	0.00% 0/4 • one month post vaccination Number of adverse events	0.00% 0/4 • one month post vaccination Number of adverse events	9.1% 1/11 • Number of events 1 • one month post vaccination Number of adverse events

Additional Information

Dr Lance Turtle

University of Liverpool

Phone: 01517957554

Email: lance.turtle@liverpool.ac.uk

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place