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Comprehensive Summary of Safety Data on Nirsevimab in Infants and Children from All Pivotal Randomized Clinical
Vaishali S Mankad1, Amanda Leach2, Yue Chang2
1Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Durham, NC 27703, USA.
Insights
Nirsevimab demonstrates a favorable safety profile for preventing respiratory syncytial virus (RSV) lower respiratory tract disease in infants. The incidence of adverse events was similar across nirsevimab, placebo, and palivizumab treatments.
Area of Science:
- Pediatrics
- Immunology
- Infectious Diseases
Background:
- Nirsevimab is approved for preventing respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants.
- It is indicated for infants during their first RSV season and vulnerable children up to 24 months.
- This analysis focuses on nirsevimab safety data from three key clinical trials.
Purpose of the Study:
- To evaluate the safety profile of nirsevimab in preventing RSV lower respiratory tract disease.
- To analyze safety data from a pre-specified analysis of three randomized controlled trials.
Main Methods:
- Data were pooled from three trials: Phase 2b, Phase 3 MELODY, and Phase 2/3 MEDLEY.
- Participants received a single intramuscular dose of nirsevimab or a comparator (placebo or palivizumab).
- Dosing varied based on infant weight and gestational age, with some participants in MEDLEY continuing into a second RSV season.
Main Results:
- Adverse events (AEs) were similar in incidence, severity, and nature across nirsevimab, placebo, and palivizumab groups.
- The vast majority of AEs (≥98%) were mild to moderate and unrelated to treatment.
- AEs of special interest, including anaphylaxis, thrombocytopenia, and immune complex disease, were infrequent and not treatment-related. Deaths were also unrelated to treatment.
Conclusions:
- A single seasonal dose of nirsevimab exhibits a favorable safety profile for RSV disease prevention.
- The safety profile is consistent regardless of infant's gestational age or presence of comorbidities.
- Nirsevimab offers a safe option for protecting infants against severe RSV disease.
Background:
Nirsevimab is approved in the US for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants during their first RSV season and in children aged ≤24 months who remain vulnerable to severe RSV disease through their second RSV season. We summarize a pre-specified analysis of nirsevimab safety data from three randomized controlled trials: Phase 2b (NCT02878330; healthy infants born ≥29 to <35 weeks' gestational age [wGA]); Phase 3 MELODY (NCT03979313; healthy infants born ≥35 wGA); and Phase 2/3 MEDLEY (NCT03959488; infants with congenital heart disease [CHD] and/or chronic lung disease of prematurity [CLD] or born ≤35 wGA).
Methods:
Participants (randomized 2:1) received a single intramuscular dose of nirsevimab or comparator (placebo, Phase 2b/MELODY; 5× once-monthly palivizumab, MEDLEY) before their first RSV season (recipients < 5 kg, nirsevimab 50 mg; ≥5 kg, nirsevimab 100 mg). In MEDLEY, children with CHD/CLD continued to a second RSV season: first-season nirsevimab recipients received nirsevimab 200 mg; first-season palivizumab recipients were re-randomized 1:1 to receive nirsevimab 200 mg or 5× once-monthly palivizumab.
Results:
The incidence, severity, and nature of AEs were similar across treatments (nirsevimab, n = 3184; placebo, n = 1284; palivizumab, n = 304). Most AEs were mild to moderate in severity, with ≥98% unrelated to treatment. AEs of special interest occurred infrequently (<1%): no anaphylaxis or thrombocytopenia were treatment-related, and no immune complex disease was reported. Deaths (incidence < 1.0%) were all unrelated to treatment.
Conclusions:
A single dose per season of nirsevimab for the prevention of RSV disease had a favorable safety profile, irrespective of wGA or comorbidities.
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