Study of Monoclonal Antibody Nirsevimab Against Respiratory Syncytial Virus (RSV) in Participants up to 24 Months of Age in India

A Phase 4, Open-label, Single-arm Clinical Study to Describe Safety and Efficacy Outcomes Associated With the Use of Nirsevimab in Neonates and Infants Born During or Entering Their First Respiratory Syncytial Virus (RSV) Season and in Children up to 24 Months of Age Who Remain Vulnerable to Severe RSV Disease Through Their Second RSV Season

The purpose of this study is to describe the safety and efficacy outcomes associated with the use of nirsevimab, administered as per routine clinical practice, in neonates and infants aged 0 to 12 months 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.

Study Overview

• Status: Active, not recruiting
• Conditions: RSV Immunization
• Intervention / Treatment: Biological: Nirsevimab

Detailed Description

Study duration: up to 16 months, including 10 months of enrollment and 6 months of follow-up

• Treatment duration: 1 day; 1 intramuscular (IM) injection

• Visit frequency:

  • 1 in-person visit for immunization (Visit [V] 01) at Day (D) 1.
  • 3 phone call visits (V2, V3 and V4) at D31 (+ 14 days), D91 (+ 14 days) and D181 (+14 days) respectively.

• Study Type: Interventional
• Enrollment (Actual): 110
• Phase: Phase 4

Contacts and Locations

Study Locations

• India
  • Bengaluru, India, 560011
    • Investigational Site Number : 3560002
  • Jaipur, India, 302007
    • Investigational Site Number : 3560008
  • Kolkata, India, 700017
    • Investigational Site Number : 3560003
  • Nagpur, India, 441108
    • Investigational Site Number : 3560007
  • New Delhi, India, 110060
    • Investigational Site Number : 3560001
  • Pune, India, 411007
    • Investigational Site Number : 3560004
  • Vizianagaram, India, 535003
    • Investigational Site Number : 3560006

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Neonates and infants aged 0 to 12 months on the day of inclusion and born during or entering their first RSV season OR children up to 24 months of age on the day of inclusion who remain vulnerable to severe RSV disease through their second RSV season

Exclusion Criteria:

Participants are excluded from the study if any of the following criteria apply:

• Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study intervention used in the study or to a product containing any of the same substances
• Known thrombocytopenia, as reported by the parent(s)/legally acceptable representative(s), contraindicating intramuscular injection
• Known bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular injection
• Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion
• Active LRTI on the day of study intervention administration
• Active RSV infection on the day of study intervention administration
• Moderate or severe acute illness/infection (according to investigator judgment) or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of study intervention administration. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided
• Receipt of palivizumab or other RSV monoclonal antibody or any RSV vaccine in the same RSV season than inclusion in the study
• Mother of the participant was administered an RSV vaccine during her pregnancy with the participant
• Receipt of immune globulins, blood or blood-derived products in the past 3 months
• Receipt of any investigational drug in the last 30 days prior to the inclusion in the study
• Participation at the time of study enrollment or in the 4 weeks preceding the study intervention administration or planned participation during the present study period, in another clinical study investigating a vaccine, drug, medical device, or medical procedure

Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Nirsevimab; Participants will receive: 1 intramuscular (IM) injection for neonates and infants aged 0 to 12 months born or entering their first RSV season at Day 01; 2 IM injections for children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season at Day 01	Biological: Nirsevimab; Pharmaceutical form:Sterile solution for injection-Route of administration:Intramuscular; Other Names: 526; Beyfortus®

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Presence of immediate adverse events (AEs)	Number of participants experiencing immediate AEs	Within 30 minutes after immunization
Presence of non-serious AEs	Number of participants experiencing non-serious AEs	From Day 01 through Day 31
Presence of adverse events of special interest (AESIs) throughout the study	Number of participants experiencing AESIs	Throughout the study (approximately 6 months)
Presence of medically attended adverse events (MAAEs) throughout the study	Number of participants experiencing MAAEs	Throughout the study (approximately 6 months)
Presence of serious adverse events (SAEs) throughout the study	Number of participants experiencing SAEs	Throughout the study (approximately 6 months)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of medically attended lower respiratory tract infection (LRTI) (outpatient and inpatient) due to reverse transcription--polymerase chain reaction (RT-PCR) confirmed RSV	Incidence of medically attended LRTI (outpatient and inpatient) due to reverse transcription--polymerase chain reaction (RT-PCR) confirmed RSV	Through 180 days after dosing
Incidence of LRTI hospitalizations due to RT-PCR confirmed RSV through 180 days after dosing	Incidence of LRTI hospitalizations due to RT-PCR confirmed RSV through 180 days after dosing	Through 180 days after dosing

Collaborators and Investigators

• Sponsor: Sanofi

Publications and helpful links

Helpful Links

• VAS00017 Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): July 31, 2025
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): June 30, 2026

Study Registration Dates

• First Submitted: July 31, 2025
• First Submitted That Met QC Criteria: July 31, 2025
• First Posted (Actual): August 7, 2025

Study Record Updates

• Last Update Posted (Actual): March 23, 2026
• Last Update Submitted That Met QC Criteria: March 19, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: nirsevimab
• Other Study ID Numbers: VAS00017; U1111-1310-0978 (Other Identifier: WHO ICTRP)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes