Nirsevimab

BEYFORTUS is a monoclonal antibody with anti-RSV activity [see Microbiology (12.4) ] .

• BEYFORTUS is indicated for the prevention of Respiratory Syncytial Virus (RSV) lower respiratory tract disease in: Neonates and infants born during or entering their first RSV season. Children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.

• BEYFORTUS is contraindicated in infants and children with a history of serious hypersensitivity reactions, including anaphylaxis, to nirsevimab-alip or to any of the excipients [see Warnings and Precautions (5.1) and Description (11) ] . BEYFORTUS is contraindicated in infants and children with a history of serious hypersensitivity reactions, including anaphylaxis, to nirsevimab-alip or to any of the excipients.contraindicated

Administer as an intramuscular injection. ( 2.1 ) Recommended dosage: Neonates and infants born during or entering their first RSV season: 50 mg if less than 5 kg in body weight. ( 2.1 ) 100 mg if greater than or equal to 5 kg in body weight. ( 2.1 ) Children who remain vulnerable through their second RSV season: 200 mg (2 × 100 mg injections). ( 2.1 ) 2.1 Recommended Dosage First RSV Season for Neonates and Infants For neonates and infants born during the RSV season, administer BEYFORTUS starting from birth. For neonates and infants born outside the RSV season, administer BEYFORTUS once prior to the start of the RSV season considering duration of protection provided by BEYFORTUS [see Clinical Pharmacology (12.2) ] . The recommended dosage of BEYFORTUS for neonates and infants born during or entering their first RSV season is based on body weight (see Table 1 ) and is administered as a single intramuscular (IM) injection. Table 1 Recommended Dosage of BEYFORTUS for the First RSV Season Body Weight at Time of Dosing Recommended Dosage Less than 5 kg 50 mg by IM injection 5 kg and greater 100 mg by IM injection Second RSV Season for Children Who Remain at Increased Risk for Severe RSV Disease For children up to 24 months of age, regardless of body weight, who remain at increased risk for severe RSV disease in their second RSV season, refer to Table 2 below for recommended dosage.

Hypersensitivity Reactions Including Anaphylaxis: Serious hypersensitivity reactions have been reported following BEYFORTUS administration. These reactions included urticaria, dyspnea, cyanosis, and/or hypotonia. Anaphylaxis has been observed with human immunoglobulin G1 (IgG1) monoclonal antibodies. If signs and symptoms of anaphylaxis or other clinically significant hypersensitivity reactions occur, initiate appropriate treatment. ( 5.1 ) 5.1 Hypersensitivity Reactions Including Anaphylaxis Serious hypersensitivity reactions have been reported following BEYFORTUS administration. These reactions included urticaria, dyspnea, cyanosis, and/or hypotonia. Anaphylaxis has been observed with human immunoglobulin G1 (IgG1) monoclonal antibodies. If signs and symptoms of anaphylaxis or other clinically significant hypersensitivity reactions occur, initiate appropriate treatment. 5.2 Use in Individuals with Clinically Significant Bleeding Disorders As with any other IM injections, BEYFORTUS should be given with caution to infants and children with thrombocytopenia, any coagulation disorder, or to individuals on anticoagulation therapy.

Most common adverse reactions were rash (0.9%) and injection site reactions (0.3%). ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Sanofi at 1-855-239-3678 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. A total of 3,224 pediatric subjects received the recommended dose of BEYFORTUS in Phase 2 and Phase 3 clinical trials (Trials 03, 04, and 05) including 2,119 infants who were born at 35 weeks gestational age (GA) or older, and 1,105 infants who were born at less than 35 weeks GA. A total of 247 infants of any GA with chronic lung disease (CLD) of prematurity or hemodynamically significant congenital heart disease (CHD) in Trial 05 received the recommended dose of BEYFORTUS. Neonates and Infants Entering Their First RSV Season (Trial 03 and Trial 04) Trial 03 was a randomized, double-blind placebo-controlled trial conducted in preterm infants born at a GA of greater than or equal to 29 weeks to less than 35 weeks. Subjects were randomized 2:1 to receive BEYFORTUS (N=968) or placebo (N=479) by IM injection. All subjects randomized to BEYFORTUS received a single 50 mg IM dose regardless of body weight.

The safety and effectiveness of BEYFORTUS in children older than 24 months of age have not been established. ( 8.4 ) 8.1 Pregnancy BEYFORTUS is not indicated for use in females of reproductive potential. 8.2 Lactation BEYFORTUS is not indicated for use in females of reproductive potential. 8.4 Pediatric Use The safety and effectiveness of BEYFORTUS have been established for the prevention of RSV lower respiratory tract disease in neonates and infants born during or entering their first RSV season and in children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season. The safety and efficacy of BEYFORTUS for this indication and populations are discussed throughout the labeling. Use of BEYFORTUS for this indication is supported by evidence from adequate and well-controlled studies in neonates and infants from birth up to 12 months of age with additional pharmacokinetic and safety data in children up to 24 months of age [see Adverse Reactions (6.1) , Clinical Pharmacology (12.3) , and Clinical Studies (14) ].

Metabolism

The PK of nirsevimab-alip is dose-proportional following a single IM administration of doses ranging from 25 mg (0.5 times the lowest approved recommended dosage) to 200 mg in pediatric subjects. Following the recommended dose, the nirsevimab-alip serum exposures were similar in neonates and infants born during or entering their first RSV season (Trials 03 and 04), and in neonates and infants born at less than 35 weeks GA (including less than 29 weeks GA) in their first RSV season (Trial 05), and in pediatric subjects up to 24 months of age with CLD or CHD in their first and second RSV season …

There is limited experience of overdose with BEYFORTUS. There is no specific treatment for an overdose with BEYFORTUS. In the event of an overdose, the individual should be monitored for the occurrence of adverse reactions and provided with symptomatic treatment as appropriate.

• Jul 17, 2023BLABLA761328Astrazeneca Ab

1. 1Drug Ineffective30820%
2. 2Respiratory Syncytial Virus Bronchiolitis28318%
3. 3Incorrect Dose Administered22514%
4. 4Respiratory Syncytial Virus Infection18112%
5. 5Bronchiolitis1358.7%
6. 6Cough966.2%
7. 7Pyrexia956.1%
8. 8Extra Dose Administered744.8%
9. 9Respiratory Syncytial Virus Test Positive503.2%
10. 10Wheezing392.5%
11. 11Product Storage Error382.4%
12. 12Dyspnoea362.3%
13. 13Oxygen Therapy352.3%
14. 14Rash352.3%
15. 15Apnoea312.0%

The 10 most recently updated of 32 ClinicalTrials.gov registrations naming Nirsevimab as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• An Observational Study to Assess Nirsevimab Immunization Rates in Eligible Infants During Their First RSV Season in the Czechia
  Not yet recruiting · Observational · 250 enrolled · Sanofi
  NCT07634692updated 2026-06-09
• RSV Immunisation Status in Queensland (Australia)
  Not yet recruiting · Observational · 1,200 enrolled · Sanofi
  NCT07615192updated 2026-05-29
• Prevention of RSV Infection in Infants by Administering Nirsevimab to Infants, With or Without Maternal RSV Vaccination
  Recruiting · Phase 3 · Interventional · 1,000 enrolled · Centre Hospitalier Annecy Genevois
  NCT07232706updated 2026-05-27
• The Immunology and Safety of Maternal RSV Vaccination (ABRYSVO), Infant Nirsevimab (BEYFORTUS) Immunization, or Both Products
  Completed · Phase 4 · Interventional · 181 enrolled · National Institute of Allergy and Infectious Diseases (NIAID)
  NCT06551506updated 2026-05-11
• THRIVE - Trial of Passive Humoral RSV Immunity for Value and Effectiveness
  Not yet recruiting · Phase 4 · Interventional · 1,000 enrolled · Menzies School of Health Research
  NCT07578298updated 2026-05-11
• A Study to Assess Safety, Pharmacokinetics Anti-Drug Antibody and Anti-RSV Antibody After 2 Doses of Nirsevimab
  Completed · Phase 3 · Interventional · 33 enrolled · AstraZeneca
  NCT06042049updated 2026-04-16
• Evaluate the Safety and Efficacy of Nirsevimab in Healthy Preterm and Term Infants in China
  Completed · Phase 3 · Interventional · 800 enrolled · AstraZeneca
  NCT05110261updated 2026-03-30
• Study of Monoclonal Antibody Nirsevimab Against Respiratory Syncytial Virus (RSV) in Participants up to 24 Months of Age in India
  Active not recruiting · Phase 4 · Interventional · 110 enrolled · Sanofi
  NCT07109297updated 2026-03-23
• Safety of RSV Preventive Monoclonal Antibody
  Recruiting · Phase 4 · Interventional · 524 enrolled · Duke University
  NCT07158814updated 2026-03-16
• Real-World Effectiveness of Nirsevimab Against RSV-Related and All-Cause Respiratory Tract Infections in Chinese Infants
  Completed · Observational · 816 enrolled · Han Tongyan
  NCT07382219updated 2026-02-03

Frequently asked questions

How does Nirsevimab work?

BEYFORTUS is a monoclonal antibody with anti-RSV activity [see Microbiology (12.4) ] .

What is Nirsevimab used for?

According to FDA labeling, Nirsevimab carries indications including: BEYFORTUS is indicated for the prevention of Respiratory Syncytial Virus (RSV) lower respiratory tract disease in: Neonates and infants born during or entering their first RSV season. Children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Nirsevimab?

Nirsevimab is classified as Antiviral monoclonal antibodies, Respiratory Syncytial Virus Anti-F Protein Monoclonal Antibody, Fusion Protein Inhibitors.

What are the brand names for Nirsevimab?

Nirsevimab is marketed under brand names including Beyfortus.

What are the contraindications for Nirsevimab?

Nirsevimab labeling lists contraindications including: BEYFORTUS is contraindicated in infants and children with a history of serious hypersensitivity reactions, including anaphylaxis, to nirsevimab-alip or to any of the excipients [see Warnings and Precautions (5.1) and Description (11) ] . BEYFORTUS is contraindicated in infants and children with a history of serious hypersensitivity reactions, including anaphylaxis, to nirsevimab-alip or to any of the excipients.. Always consult the full prescribing information and a clinician.