RWE shows efficacy of nirsevimab for infant RSV

Infants under 12 months who received a single dose of monoclonal antibody (mAb) nirsevimab showed an 83.21 percent reduction in hospitalisations due to respiratory syncytial virus (RSV)-related lower respiratory tract disease (LRTD), according to new real-world data from a Phase IIIb trial.

Results from the Hospitalized RSV Monoclonal Antibody Prevention (HARMONIE) study were presented at 41st Annual Meeting of the European Society for Paediatric Infectious Diseases. HARMONIE investigated the efficacy and safety of a single intramuscular dose of nirsevimab.

Real-world data

The real-world data “adds to the evidence that use of long-acting monoclonal antibody may prevent moderate to severe RSV disease after a convenient single dose,” Professor Peter Openshaw, Professor of Experimental Medicine at Imperial College London commented.

With the data having been collected in a real-world (RW) setting during the 2022-2023 RSV season, it was “gathered at a time when RSV was recovering from the dip in case numbers during COVID lockdown” Professor Openshaw added.

Thomas Triomphe, Executive Vice President of Vaccines at Sanofi shared: “The HARMONIE data demonstrate the real-world impact nirsevimab has on paediatric hospitalisations.” This is important, Professor Openshaw noted, because RSV is “the major single cause of hospitalisation in this age-group”.

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The Phase III trial of the monoclonal antibody treatment

Over 8,000 infants were evaluated in the clinical trial. HARMONIE compared nirsevimab treatment to no intervention (standard of care). Nirsevimab, a long-acting antibody, is being developed jointly by Big Pharma companies Sanofi and AstraZeneca. Agreed in March 2017, AstraZeneca leads development and manufacturing activities, and Sanofi leads commercialisation activities.

Real-world data from the Phase IIIb trial also showed that nirsevimab reduced the incidence of hospitalisations due to severe RSV-related LRTD by 75.71 percent. The mAb demonstrated a reduction of 58.04 percent in the incidence of all-cause LRTD hospitalisation compared to infants who received no RSV intervention.

Throughout HARMONIE, nirsevimab maintained a favourable safety profile, consistent with the pivotal trial results. Participant follow-up will conclude at 12 months.