Efficacy, Immunogenicity, and Safety Study of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers

JRCT ID: jRCT2031230744

Registered date:28/03/2024

Basic Information

• Recruitment status: Recruiting
• Health condition(s) or Problem(s) studied: RSV immunisation
• Date of first enrollment: 15/04/2024
• Target sample size: 6300
• Countries of recruitment: Argentina,Japan,Honduras,Japan,United States,Japan
• Study type: Interventional

Intervention(s)

Drug (Biological): RSVt Vaccine
- Pharmaceutical form: Suspension of virus in a nasal spray, Route of administration: Intranasal
Drug (Biological): Placebo
- Pharmaceutical form: Suspension in a nasal spray, Route of administration: Intranasal

Arm description:
Experimental: Group 1 RSVt Vaccine
Participants will receive 2 intranasal administrations of RSVt vaccine
Placebo Comparator: Group 2 Control
Participants will receive 2 intranasal administrations of placebo

Outcome(s)

Primary Outcome

1. Occurrence of lower respiratory disease (LRTD) (during respiratory syncytial virus [RSV] Season 1) associated with any reverse transcription polymerase chain reaction (RT-PCR) confirmed RSV strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of LRTD associated with any RT-PCR confirmed RSV strain, assessed up to the end of RSV season 1 (ie. up to 12 months post-dose 1)]

Secondary Outcome

<Time frame for evaluation>
#1 to #16 are assessed up to the end of RSV season 1 (ie. up to 12 months post-dose 1) and #17 to #22 are assessed up to the end of the study (ie. up to 24 months post-dose 1).

1. Occurrence of upper respiratory disease (URTD) (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of URTD associated with any RT-PCR confirmed RSV strain]
2. Occurrence of LRTD (during RSV Season 1) associated with any RT-PCR confirmed RSV strain leading to hospitalization > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of LRTD associated with any RT-PCR confirmed RSV strain leading to hospitalization]
3. Occurrence of severe LRTD (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of severe LRTD associated with any RT-PCR confirmed RSV strain]
4. Occurrence of urgent care visits, associated with an episode of LRTD over RSV Season 1, associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of urgent care visit associated with an episode of LRTD associated with any RT-PCR confirmed RSV strain]
5. Occurrence of acute respiratory disease (ARD) (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of ARD associated with any RT-PCR confirmed RSV strain]
6. Occurrence of hospitalizations, associated with an episode of ARD over RSV Season 1, associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of hospitalizations associated with an episode of ARD associated with any RT-PCR confirmed RSV strain]
7. Occurrence of urgent care visits, associated with an episode of ARD over RSV Season 1, associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of urgent care visit associated with an episode of ARD associated with any RT-PCR confirmed RSV strain]
8. Occurrence of LRTD (during RSV Season 1) associated with an RT-PCR confirmed RSV A or B strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of LRTD associated with an RT-PCR confirmed RSV A or B]
9. Occurrence of URTD (during RSV Season 1) associated with an RT-PCR confirmed RSV A or B strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of URTD associated with an RT-PCR confirmed RSV A or B]
10. Occurrence of ARD (during RSV Season 1) associated with an RT-PCR confirmed RSV A or B strain > 21 days post-dose 2
[Time Frame: from 22 days post-dose 2 up to the start date of first occurrence of ARD associated with an RT-PCR confirmed RSV A or B]
11. Occurrence of LRTD (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 1
[Time Frame: from 22 days post-dose 1 up to the start date of first occurrence of LRTD associated with any RT-PCR confirmed RSV strain]"
12. Occurrence of URTD (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 1
[Time Frame: from 22 days post-dose 1 up to the start date of first occurrence of URTD associated with any RT-PCR confirmed RSV strain]
13. Occurrence of ARD (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 1
[Time Frame: from 22 days post-dose 1 up to the start date of first occurrence of ARD associated with any RT-PCR confirmed RSV strain]
14. Occurrence of LRTD (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2, in RSV-exposed participants
[Time Frame: same as the primary outcome-1]
15. Occurrence of URTD (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2, by baseline serostatus
[Time Frame: same as the secondary outcome-1]
16. Occurrence of ARD (during RSV Season 1) associated with any RT-PCR confirmed RSV strain > 21 days post-dose 2, by baseline serostatus
[Time Frame: same as the secondary outcome-5]
17. Occurrence of LRTD (during RSV Season 2), associated with any RT-PCR confirmed RSV strain
[Time Frame: from 12 months post-dose 1 up to the start date of first occurrence of LRTD associated with any RT-PCR confirmed RSV strain]
18. Occurrence of URTD (during RSV Season 2), associated with any RT-PCR confirmed RSV strain
[Time Frame: from 12 months post-dose 1 up to the start date of first occurrence of URTD associated with any RT-PCR confirmed RSV strain]
19. Occurrence of ARD (during RSV Season 2), associated with any RT-PCR confirmed RSV strain
[Time Frame: from 12 months post-dose 1 up to the start date of first occurrence of ARD associated with any RT-PCR confirmed RSV strain]
20. Occurrence of LRTD (during RSV Season 2), associated with any RT-PCR confirmed RSV strain, by baseline serostatus
[Time Frame: same as the secondary outcome-17]
21. Occurrence of URTD (during RSV Season 2), associated with any RT-PCR confirmed RSV strain, by baseline serostatus
[Time Frame: same as the secondary outcome-18]
22. Occurrence of ARD (during RSV Season 2), associated with any RT-PCR confirmed RSV strain, by baseline serostatus
[Time Frame: same as the secondary outcome-19]
23. Presence of solicited administration site reactions within 21 days after each vaccination
[Time Frame: Within 21 days after each vaccination]
Number of participants experiencing solicited site reactions
24. Presence of solicited systemic reactions within 21 days after each vaccination
[Time Frame: Within 21 days after each vaccination]
Number of participants experiencing solicited systemic reactions
25. Presence of unsolicited systemic adverse events (AEs) reported in the 30 minutes after each vaccination
[Time Frame: Within 30 minutes after each vaccination]
Number of participants experiencing immediate unsolicited systemic AEs
26. Presence of unsolicited AEs within 28 days after each vaccination
[Time Frame: Within 28 days after each vaccination]
Number of participants experiencing unsolicited AEs
27. Presence of medically attended adverse events (MAAEs) throughout the study
[Time Frame: Throughout the study (approx. 24 months)]
Number of participants experiencing MAAEs
28. Presence of serious adverse events (SAEs) throughout the study
[Time Frame: Throughout the study (approx. 24 months)]
Number of participants experiencing SAEs
29. Presence of adverse events of special interest (AESIs) throughout the study
[Time Frame: Throughout the study (approx. 24 months)]
Number of participants experiencing AESIs
30. RSV A serum neutralizing antibody (Nab) titers at Day (D) 01
[Time Frame: D01]
Antibody (Ab) titers are expressed as geometric mean titers (GMTs) at baseline. The same goes for #31, #34, #35.
31. RSV B serum Nab titers at D01
[Time Frame: D01]
32. RSV A serum Nab titers at 28 days post-dose 2
[Time Frame: 28 days post-dose 2]
Ab titers are expressed as GMTs at post-baseline. The same goes for #33, #36, and #37.
33. RSV B serum Nab titers at 28 days post-dose 2
[Time Frame: 28 days post-dose 2]
34. RSV serum anti-F Immunoglobulin (Ig) A Electrochemiluminescence (ECL) Ab titers at D01
[Time Frame: D01]
35. RSV serum anti-F IgG ECL Ab titers at D01
[Time Frame: D01]
36. RSV serum anti-F IgA ECL Ab titers at 28 days post-dose 2
[Time Frame: 28 days post-dose 2]
37. RSV serum anti-F IgG ECL Ab titers at 28 days post-dose 2
[Time Frame: 28 days post-dose 2]

Key inclusion & exclusion criteria

• Age minimum: >= 6month old
• Age maximum: <= 21month old
• Gender: Both

Include criteria

- Aged 6 months to < 22 months on the day of inclusion (means the day of the 6-month birthday to the day before the 22-month birthday)
- Participants who are healthy as determined by medical evaluation including medical history
- Born at full term of pregnancy (>= 37 weeks)

Exclude criteria

Participants are excluded from the study if any of the following criteria apply:
- Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months)
- Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study intervention used in the study or to a product containing any of the same substances
- Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion
- History of medically diagnosed wheezing
- Any acute febrile illness in the past 48 hours that according to investigator judgment is significant enough to interfere with successful inoculation on the day of vaccination. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
- Probable or confirmed ongoing case of viral respiratory infection (including COVID-19, influenza, rhinovirus, etc.) at the time of enrollment. A prospective participant should not be included in the study until the respiratory infection has resolved.
- Member of a household that contains an immunocompromised individual, including, but not limited to:
- - a person who is human immunodeficiency virus (HIV) infected
- - a person who has received chemotherapy within the 12 months prior to study enrollment
- - a person who has received (within the past 6 months) or is receiving (at the time of enrollment) immunosuppressant agents
- - a person living with a solid organ or bone marrow transplant
- Potential close contact with other immunocompromised individual within 30 days after each vaccination as per investigator's discretion
- Participant's biological mother's previous receipt or planned administration of an investigational respiratory syncytial virus (RSV) vaccine during pregnancy and/or breastfeeding
- Receipt or planned receipt of any of the following vaccines prior to enrollment or after the first study intervention administration:
- - Any other intranasal live attenuated vaccine within the 28 days prior to and after Dose 1 study administration
- - Unless given on the day of Dose 1 study administration, any other injectable live attenuated vaccines within the 28 days prior to and after. Concomitant receipt on the day of Dose 1 study administration is allowed.
- Previous receipt of an investigational RSV vaccine or receiving any anti-RSV product (such as ribavirin or RSV immune globulin) at the time of enrollment. Previous receipt of an RSV monoclonal antibody within 6 months prior to the first study vaccine administration.
- Receipt of immune globulins, blood or blood-derived products in the past 3 months
- Receipt of intranasal and intra-ocular medications within 3 days prior to study enrollment
- Participation at the time of study enrollment or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure

Related Information

• Primary Sponsor: Tanaka Tomoyuki
• Secondary ID(s): NCT06252285,2023-505762-29