Dr John Campbell - New mRNA trial suspended - Severe respiratory disease safety signal

RELEASED DECEMBER 23, 2024

Vaccine-associated enhanced respiratory disease

Vaccines and Related Biological Products Advisory Committee December 12, 2024 Meeting Announcement

https://www.fda.gov/advisory-committees/advisory-committee-calendar/vaccines-and-related-biological-products-advisory-committee-december-12-2024-meeting-announcement

Entire briefing document

https://www.fda.gov/media/184301/download

Pediatric RSV vaccine trial enrollment on hold in US, VRBPAC says
https://www.contemporarypediatrics.com/view/pediatric-rsv-vaccine-trial-enrollment-on-hold-in-us-vrbpac-says

The halt follows a severe respiratory disease safety signal observed in a July 2024 phase 1 trial of Moderna's mRNA-1345 and mRNA-1365 vaccine candidates.

A phase I trial

The effects of the medication on about 20 to 80 healthy volunteers

To evaluating safety and ideal dosage

70% move on to phase II

This study, safety, tolerability, and immunogenicity

Who were the subjects

Children aged younger than 2 years

Respiratory syncytial virus (RSV) -naïve children aged 2 through 5 years

The halt of this mRNA RSV vaccine

Severe respiratory disease safety signal

Safety signal led to study pause

Potential safety signal for RSV severe lower respiratory tract illness (sLRTI) was identified.

An imbalance in cases of RSV sLRTI was also observed,

with more cases present among vaccine groups compared to control group counterparts,

5 cases in the mRNA-1345/1365 15 µg groups compared to 1 case in the part B placebo group.

Of these 6 cases, 5 required hospitalization, including 1 infant who required mechanical ventilation.

which raised concern for vaccine-associated enhanced respiratory disease.

The protocol’s study pause criterion of any sLRTI with positive polymerase chain reaction (PCR) for RSV in ≥2 participants was met.

One, two and three dose parts planned

Part A (Cohorts 1 and 2)

30 µg mRNA-1345, 30 µg mRNA-1365, and placebo

approximately 90 participants 8 months to less than 24 months of age

(randomized in a 1:1:1 ratio, respectively)."

"Part B (Cohorts 3 through 6)

2 dose levels of mRNA-1345 and mRNA-1365 and placebo

Approximately 120 participants 5 months to less than 8 months of age

(randomized in a 1:1:1 ratio, respectively)

Part C (Cohorts 7 and 8)

3 doses of 30 µg mRNA-1345

Approximately 100 participants 8 months to less than 12 months of age

who have (Cohort 7) or have not (Cohort 8) previously received nirsevimab.

VRBPAC meeting and outlook

Vaccines and Related Biological Products Advisory Committee

Vaccine-associated enhanced respiratory disease

Currently considering criteria for recommencement

https://www.youtube.com/watch?v=lJlq3sDL-BI