SYNAGIS

What it is

Synagis (palivizumab) is a humanized IgG1 monoclonal antibody directed to an epitope in the A antigenic site of the fusion protein of respiratory syncytial virus (RSV). This humanized monoclonal antibody is composed of 95% human and 5% murine amino acid sequences. Synagis is supplied as a clear or slightly opalescent sterile solution in clear glass vials. It is available as 50 mg/0.5 mL and 100 mg/1 mL single-use vials.

Approved indications

Synagis is indicated for the prevention of serious lower respiratory tract disease caused by respiratory syncytial virus (RSV) in children at high risk of RSV disease. Safety and efficacy were established in the following patient populations: — Children with bronchopulmonary dysplasia (BPD) — Infants with a history of prematurity (gestational age less than or equal to 35 weeks at birth) — Children with haemodynamically significant congenital heart disease (CHD)

Dosing overview

The recommended dose of Synagis is 15 mg/kg of body weight, given once a month during anticipated periods of RSV risk in the community. Palivizumab is administered intramuscularly, preferably in the anterolateral aspect of the thigh. Where possible, the first dose should be administered prior to commencement of the RSV season and subsequent doses should be administered monthly throughout the RSV season. Injection volumes over 1 mL should be given as a divided dose.

Key safety warnings

Allergic reactions including very rare anaphylaxis and anaphylactic shock have been reported following palivizumab administration, and in some cases, fatalities have been reported. Medications for the treatment of severe hypersensitivity reactions, including anaphylaxis and anaphylactic shock, should be available for immediate use following administration of Synagis. As with any intramuscular injection, Synagis should be given with caution to patients with thrombocytopenia or any coagulation disorder. Palivizumab may interfere with immune-based RSV diagnostic tests such as some antigen detection-based assays and viral culture assays, but does not interfere with reverse transcriptase polymerase chain reaction-based assays, and assay interference could lead to false-negative RSV diagnostic test results.

Contraindications

Synagis is contraindicated in patients with known hypersensitivity to Synagis or to any of its excipients, and is also contraindicated in patients with known hypersensitivity to other humanised monoclonal antibodies.

Regulatory history

Synagis palivizumab 100 mg/1 mL solution for injection vial and 50 mg/0.5 mL solution for injection vial were first listed on the Australian Register of Therapeutic Goods on 24 September 2015.