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ENFLONSIATM (clesrovimab-cfor) storage & handling

A 30-month shelf life from date of manufacture when following storage instructions below1

Purchased ENFLONSIA doses may be used for the next RSV season for infants entering their first RSV season.

Before storing for next season, it is important to check the expiration date to ensure the product won’t expire during off season storage.

Storage & handling

  • Store prefilled syringes under refrigeration at 36°F to 46°F (2°C to 8°C)
  • Keep the prefilled syringe in the original carton to protect from light until time of use
  • ENFLONSIA may be kept at room temperature between 68°F to 77°F (20°C to 25°C) for a maximum of 48 hours
  • After removal from the refrigerator, ENFLONSIA must be used within 48 hours or discarded
  • Do not freeze. Do not shake
  • 30-month shelf life1
  • Package dimensions: Pack of 1: 44 x 105 x 29 mm, Pack of 10: 105 x 133 x 41 mm

Single doses available!

Not actual size shown

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Frequently asked questions

See clinical data for ENFLONSIA

Reference:

  1. US Food & Drug Administration Center for Drug Evaluation and Research. BLA Approval Letter. Published June 9, 2025. Accessed October 21, 2025. https://www.accessdata.fda.gov/drugsatfda_docs/nda/2025/761432Orig1s000Approv.pdf

Indications and Usage

ENFLONSIA is indicated for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants who are born during or entering their first RSV season.

Selected Safety Information

  • Do not administer ENFLONSIA to infants with a history of serious hypersensitivity reactions, including anaphylaxis, to any component of ENFLONSIA.
  • Serious hypersensitivity reactions, including anaphylaxis, have been observed with other human immunoglobulin G1 (IgG1) monoclonal antibodies. If signs or symptoms of a clinically significant hypersensitivity reaction or anaphylaxis occur, initiate appropriate medications and/or supportive therapy.
  • ENFLONSIA may interfere with some immunologically-based RSV diagnostic assays (i.e., rapid antigen tests) as observed in laboratory studies. Confirmation using a reverse transcriptase polymerase chain reaction (RT-PCR) assay is recommended when rapid antigen assay results are negative and clinical observations are consistent with RSV infection.
  • The most common adverse reactions were injection-site erythema (3.8%), injection-site swelling (2.7%), and rash (2.3%).

 

Dosage and Administration

  • The recommended dose is 105 mg administered as a single intramuscular (IM) injection.
  • For neonates and infants born during the RSV season, administer ENFLONSIA once starting from birth. For infants born outside the RSV season, administer ENFLONSIA once prior to the start of their first RSV season considering 5 months duration of protection by ENFLONSIA.
  • For infants undergoing cardiac surgery with cardiopulmonary bypass during or entering their first RSV season, an additional 105 mg dose is recommended as soon as the infant is stable after surgery to ensure adequate clesrovimab-cfor serum levels.

 

Before administering ENFLONSIA, please read the accompanying Prescribing Information. The Patient Information also is available.

Indications and Usage
Selected Safety Information

ENFLONSIA is indicated for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants who are born during or entering their first RSV season.

Selected Safety Information

  • Do not administer ENFLONSIA to infants with a history of serious hypersensitivity reactions, including anaphylaxis, to any component of ENFLONSIA.
  • Serious hypersensitivity reactions, including anaphylaxis, have been observed with other human immunoglobulin G1 (IgG1) monoclonal antibodies. If signs or symptoms of a clinically significant hypersensitivity reaction or anaphylaxis occur, initiate appropriate medications and/or supportive therapy.
  • ENFLONSIA may interfere with some immunologically-based RSV diagnostic assays (i.e., rapid antigen tests) as observed in laboratory studies. Confirmation using a reverse transcriptase polymerase chain reaction (RT-PCR) assay is recommended when rapid antigen assay results are negative and clinical observations are consistent with RSV infection.
  • The most common adverse reactions were injection-site erythema (3.8%), injection-site swelling (2.7%), and rash (2.3%).

 

Dosage and Administration

  • The recommended dose is 105 mg administered as a single intramuscular (IM) injection.
  • For neonates and infants born during the RSV season, administer ENFLONSIA once starting from birth. For infants born outside the RSV season, administer ENFLONSIA once prior to the start of their first RSV season considering 5 months duration of protection by ENFLONSIA.
  • For infants undergoing cardiac surgery with cardiopulmonary bypass during or entering their first RSV season, an additional 105 mg dose is recommended as soon as the infant is stable after surgery to ensure adequate clesrovimab-cfor serum levels.

 

Before administering ENFLONSIA, please read the accompanying Prescribing Information. The Patient Information also is available.