• [ 메디채널 김갑성 기자 ] Beyfortus (nirsevimab) is the only option that can offer RSV protection designed for all infants with proven high, sustained efficacy, favourable safety and public health impact demonstrated in the real world.^[1]
• In the recent HARMONIE trial findings, Beyfortus reduced RSV hospitalisations in infants by 82.7% (95% CI: 67.8 to 91.5; p<0,0001) through six months (180 days). ^{[2], [3]}
• Administration can be timed during the first year of life to provide protection from birth, or as early as possible.

SINGAPORE, Aug. 19, 2025 -- The Health Sciences Authority (HSA) has approved Sanofi and AstraZeneca's BEYFORTUS (nirsevimab) for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in newborns and infants born during or entering their first RSV season, and for children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.

Globally, around 2 in 3 babies will catch RSV before their first birthday^[4] and it remains the most common cause of lower respiratory tract disease, including bronchiolitis and pneumonia, in infants^[5]. RSV is also a leading cause of hospitalisation among infants in Singapore, with most cases occurring in otherwise healthy, full-term babies. Each year, approximately 1,804 children under 29 months are hospitalised due to RSV-related illness^[6-10].

A panel of leading paediatricians in Singapore recently published an expert consensus, underscoring the urgent need for RSV protection in all infants. They concur that nirsevimab is key to alleviating the RSV burden on the healthcare system and recommend that immunisation be considered for all infants under the National Immunisation Programme in Singapore.^[11]

Zainab Sadat, Head of Vaccines, Sanofi Southeast Asia & India

"Today, Singapore joins other countries worldwide where an innovative immunisation solution is now available to protect all infants against RSV. The approval of BEYFORTUS marks a critical step towards giving parents the ability to protect their babies during their first year of life, when they are most vulnerable to severe RSV disease. We are committed to working with stakeholders across the RSV care continuum to ensure seamless implementation and broad availability of this innovative preventive solution — because every baby needs protection. Our goal is simple: to help parents protect their babies, and give them peace of mind."

The approval was based on results from the extensive BEYFORTUS clinical development programme spanning three pivotal late-stage clinical trials. Across all clinical endpoints, a single dose of BEYFORTUS demonstrated high and consistent efficacy against RSV disease sustained for at least five months. BEYFORTUS was well tolerated with a favourable safety profile that was consistent across all clinical trials. The overall rates of adverse events were comparable between BEYFORTUS and placebo and the majority of adverse events were mild or moderate in severity.

In temperate countries, the single administration of BEYFORTUS was developed to correspond with the beginning of the RSV season for babies born prior to the season or at birth for those born during the RSV season. In clinical trials, BEYFORTUS helped prevent RSV disease requiring medical care in all infant populations studied, including those born healthy, at term or preterm, or with specific health conditions that make them vulnerable to severe RSV disease. RSV disease requiring medical care included physician office, urgent care, emergency room visits and hospitalisations.

About RSV

RSV is a highly contagious virus that can lead to serious respiratory illness for infants.^[5] It is a leading cause of hospitalisation in all infants, with most hospitalisations for RSV occurring in otherwise healthy infants born at term^[6-10]. Two out of three infants are infected with RSV during their first year of life and almost all children are infected by their second birthday^[4]. Globally, in 2019, there were approximately 33 million cases of acute lower respiratory infections leading to more than three million hospitalisations, and it was estimated that there were 26,300 in-hospital deaths of children younger than five years^[12]. RSV-related direct medical costs, globally — including hospital, outpatient and follow-up care — were estimated at €4.82 billion in 2017^[13].

About BEYFORTUS

BEYFORTUS (nirsevimab) is the first immunisation designed for all newborns and infants for protection against RSV disease through their first RSV season, including for those born healthy at term or preterm, or with specific health conditions. It is also indicated for children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.

As a long-acting antibody provided directly to newborns and infants as a single dose, BEYFORTUS offers rapid protection to help prevent lower respiratory tract disease caused by RSV without requiring activation of the immune system. BEYFORTUS administration can be timed to coincide with the RSV season.

BEYFORTUS has been approved for use in the European Union, the US, China, Japan, and many other countries around the world. Special designations to facilitate expedited development of BEYFORTUS were granted by several regulatory agencies, including Breakthrough Therapy Designation and Priority Review designation by The China Center for Drug Evaluation under the National Medical Products Administration; Breakthrough Therapy Designation and Fast Track Designation from the US Food and Drug Administration; access granted to the European Medicines Agency (EMA) PRIority MEdicines (PRIME) scheme and EMA accelerated assessment; Promising Innovative Medicine designation by the UK Medicines and Healthcare products Regulatory Agency; and BEYFORTUS has been named "a medicine for prioritized development" under the Project for Drug Selection to Promote New Drug Development in Pediatrics by the Japan Agency for Medical Research and Development.

About the clinical trials

The Phase 2b trial^[14] was a randomised, placebo-controlled trial designed to measure the efficacy of BEYFORTUS against medically attended lower respiratory tract disease (LRTD) caused by RSV through 150 days post-dose in healthy preterm infants of 29 to less than 35 weeks' gestation (n=1,453). Infants were randomised (2:1) to receive a single 50 mg intramuscular injection of BEYFORTUS (n=969) or placebo (n=484) regardless of weight at the RSV season start. The primary endpoint was met, significantly reducing the incidence of medically attended RSV LRTD by 70.1% (95% CI: 52.3, 81.2; P<0.001) compared to placebo. In a prespecified secondary endpoint, BEYFORTUS reduced medically attended RSV LRTD with hospitalisation by 78.4% (95% CI 51.9, 90.3) versus placebo.

The BEYFORTUS dosing regimen was determined based on further exploration of the Phase 2b data and was used in subsequent trials as a single 50 mg dose for infants who weigh less than 5 kg, or a single 100 mg dose for those who weigh 5 kg or greater. A post-hoc analysis of the Phase 2b study that applied the recommended 50 mg dose in a subgroup of infants weighing less than 5 kg showed the efficacy of BEYFORTUS against medically attended RSV LRTD and medically attended RSV LRTD with hospitalisation was 86.2% (95% CI 68.0, 94.0) and 86.5% (95% CI 53.5, 96.1), respectively.

The Phase 3 MELODY trial^[15] was a randomised, double-blind, placebo-controlled trial conducted across 21 countries designed to determine the safety and efficacy of BEYFORTUS against medically attended LRTD caused by RSV in healthy term and late preterm infants (35 weeks gestational age or greater) entering their first RSV season, including efficacy against severe disease such as hospitalisation, through 150 days after dosing. The primary endpoint was met, reducing the incidence of medically attended RSV LRTD by 74.5% (95% CI 49.6, 87.1; P<0.001) compared to placebo. The efficacy of BEYFORTUS against the secondary endpoint of hospitalisation was 62.1% (-8.6, 86.8). A pre-specified pooled analysis of the Phase 3 MELODY trial showed the efficacy of BEYFORTUS against medically attended RSV LRTD and medically attended RSV LRTD with hospitalisation was 79.5% (95% CI 65.9, 87.7; P<0.0001) and 77.3% (95% CI 50.3, 89.7; P<0.001), respectively.

MEDLEY was a Phase 2/3^[16], randomised, double-blind, palivizumab-controlled trial with the primary objective of assessing safety and tolerability for BEYFORTUS in preterm infants of less than 35 weeks' gestational age and infants with congenital heart disease (CHD) and/or chronic lung disease (CLD) of prematurity eligible to receive palivizumab. Between July 2019 and May 2021, a total of 925 infants at higher risk for severe RSV disease entering their first RSV season were randomised to receive BEYFORTUS or palivizumab. Safety was assessed by monitoring the occurrence of treatment emergent adverse events (TEAEs) and treatment emergent severe adverse events (TESAEs) through 360 days post-dose. Serum levels of BEYFORTUS following dosing (on day 151) in this trial were comparable with those observed in the Phase 3 MELODY trial, indicating similar protection in this population to that in healthy term and late preterm infants is likely.

BEYFORTUS was well tolerated with a favourable safety profile that was similar to palivizumab in the MEDLEY Phase 2/3 trial and consistent with the safety profile in healthy term and preterm infants compared to placebo across the MELODY and Phase 2b trials. The overall rates of adverse events were comparable between BEYFORTUS and placebo and the majority of adverse events were mild or moderate in severity.

The results of MELODY, Phase 2/3 MEDLEY and the Phase 2b trials illustrate that BEYFORTUS helped prevent RSV disease requiring medical care in all infant populations studied, including those born healthy at term or preterm, or with specific health conditions that make them vulnerable to severe RSV disease. RSV disease requiring medical care included physician office, urgent care, emergency room visits and hospitalisations.^[11]

These trials form the basis of regulatory submissions that began in 2022.

Another study, the Hospitalized RSV Monoclonal Antibody Prevention (HARMONIE) trial^{[2], [3]}, was a large European interventional clinical trial in 250 sites and including over 8,000 infants aiming to determine the efficacy and safety of a single intramuscular (IM) dose of BEYFORTUS (<5 kg 50 mg; ≥5 kg 100 mg), compared to no intervention (standard of care), for the prevention of hospitalisations due to RSV-related LRTD in infants under 12 months of age who are not eligible to receive palivizumab.

The data from HARMONIE show that BEYFORTUS reduced the incidence of hospitalisations due to RSV-related LRTD by 82.7% (95% CI: 67.8-91.5; p<0.0001) through 180 days after administration compared to no intervention, exceeding the typical length of the five-month RSV season. The high efficacy of 83.2% previously reported in the primary analysis was sustained over the longer follow-up period with no evidence of waning protection in infants born before or during the RSV season. BEYFORTUS maintained a favorable safety profile, consistent with clinical study results. ^{[2], [3]}

About Sanofi

Sanofi is an R&D driven, AI-powered biopharma company committed to improving people's lives and delivering compelling growth. We apply our deep understanding of the immune system to invent medicines and vaccines that treat and protect millions of people around the world, with an innovative pipeline that could benefit millions more. Our team is guided by one purpose: we chase the miracles of science to improve people's lives; this inspires us to drive progress and deliver positive impact for our people and the communities we serve, by addressing the most urgent healthcare, environmental, and societal challenges of our time.

For more information, visit www.sanofi.com.

Sanofi Forward-Looking Statements

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References

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