Therese Takas (United States of America)
AstraZeneca -Author Of 1 Presentation
POOLED EFFICACY OF NIRSEVIMAB AGAINST RSV LOWER RESPIRATORY TRACT INFECTION IN PRETERM AND TERM INFANTS
Abstract
Backgrounds:
Nirsevimab reduced medically attended (MA) respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) incidence in two double-blind, placebo-controlled studies (Phase IIb [NCT02878330]: healthy very and moderately preterm infants ≥29 to <35 weeks gestational age [wkGA], efficacy 70.1%; Phase III: MELODY [NCT03979313], healthy term and late preterm infants ≥35 wkGA, efficacy 74.5%). We report a pooled efficacy analysis of nirsevimab in term and preterm infants ≥29 wkGA through Day 151.
Methods
Infants were randomised 2:1 to receive either an intramuscular injection of nirsevimab (<5 kg, 50 mg; ≥5 kg, 100 mg) or placebo, before their first RSV season. Data were pooled from the Phase IIb and MELODY studies for those infants under the optimised dosing regimen (i.e., infants <5 kg at dosing and receiving the 50 mg dose from Phase IIb and all infants in MELODY) to evaluate efficacy (relative risk reduction versus placebo) against varying severities of MA RSV LRTI.
Results:
Overall, 860 infants from Phase IIb (median age at randomisation: 1.60 [range 0.1–6.4] months; female: 47.6%) and 1490 infants from MELODY (median age at randomisation: 2.60 [0.03–11.10] months; female: 48.4%) were included. Demographics were comparable across studies, except for GA and age at randomisation. Nirsevimab had an efficacy of 79.5% against MA RSV LRTI, 77.3% against RSV LRTI hospitalisation and 86.0% against very severe RSV LRTI through Day 151 (Figure). Consistent efficacy was observed across subgroups defined by age at randomisation, sex, ancestry, weight or geographical region and across endpoints of differing disease severity.
Conclusions/Learning Points:
In a pooled analysis of two randomised, placebo-controlled studies, prophylaxis with nirsevimab demonstrated consistent efficacy across severities of RSV LRTI through Day 151.
