Palivizumab (Monograph)

Brand name: Synagis
Drug class: Monoclonal Antibodies
VA class: AM800
CAS number: 188039-54-5

Medically reviewed by Drugs.com on Dec 11, 2024. Written by ASHP.

Introduction

Antiviral; recombinant humanized monoclonal antibody directed against the F surface glycoprotein of respiratory syncytial virus (RSV).

Uses for Palivizumab

Respiratory Syncytial Virus (RSV) Infections

Prevention of serious lower respiratory tract infections caused by RSV in pediatric patients at high risk for RSV disease. May reduce severity of RSV infection and reduce frequency and duration of RSV-related hospitalizations in these high-risk patients.

FDA-approved labeling defines high risk pediatric patients as infants with a history of premature birth (≤35 weeks gestational age) and who are ≤6 months of age at the beginning of RSV season; infants and young children ≤24 months of age with chronic lung disease of prematurity (CLD) (e.g., bronchopulmonary dysplasia [BPD]) that required medical treatment within the previous 6 months; and infants and young children with hemodynamically significant congenital heart disease (CHD) who are <24 months of age at the beginning of the RSV season.

The American Academy of Pediatrics (AAP) has published guidelines on the use of palivizumab. The guidelines state that palivizumab may be considered to reduce the risk of RSV-associated hospitalizations in carefully selected children at significantly increased risk of severe disease. For the most recent updates, consult the AAP website at [Web]

Palivizumab is not indicated and should not be used for treatment of RSV infection.

Palivizumab Dosage and Administration

General

Administration Precautions

Infants and children with thrombocytopenia or any coagulation disorder should be given IM injections with caution.

Administration

IM Administration

Administer IM, preferably in anterolateral aspect of the thigh. Avoid gluteal muscle because of risk of damage to sciatic nerve.

Has been administered by IV infusion^{† [off-label]} over 3–5 minutes in a limited number of infants, but manufacturer states the currently available formulation is intended for IM injection only.

Do not shake or agitate the vial.

Supplied as a clear, or slightly opalescent, solution in single-dose vials. Do not use if particulate matter or discoloration is observed.

Administer immediately after withdrawal from vial. Vial is for single use only; discard any unused portion.

Dosing volumes >1 mL should be divided and injected IM at different sites.

Dosage

Pediatric Patients

Prevention of Respiratory Syncytial Virus (RSV) Infections

Preterm Infants, Infants and Young Children with CLD, Infants and Young Children with CHD

15 mg/kg once monthly. Administer first dose prior to beginning of RSV season and subsequent doses once monthly until end of season.

AAP states that for most seasons and in most regions of the northern hemisphere, give first dose at beginning of November and the last dose at beginning of March; these 5 doses usually provide protection during the entire season. However, decisions about the specific duration of prophylaxis should be individualized according to the duration of the local RSV season.

Children undergoing cardiopulmonary bypass should receive a supplemental 15-mg/kg dose as soon as possible after the procedure (even if this is <1 month after the last dose). Thereafter, administer usual doses once monthly.

Manufacturer states that children who develop RSV infection should continue receiving monthly doses for the duration of the RSV season. However, AAP recommends to discontinue monthly prophylaxis in such patients because of the low likelihood of a second RSV hospitalization in the same season.

Cautions for Palivizumab

Contraindications

History of a previous significant hypersensitivity reaction to the drug.

Warnings/Precautions

Hypersensitivity Reactions

Severe acute hypersensitivity reactions, including fatal anaphylaxis, reported.

Signs and symptoms may include urticaria, pruritus, angioedema, dyspnea, respiratory failure, cyanosis, hypotonia, hypotension, and unresponsiveness.

If a severe hypersensitivity reaction occurs, permanently discontinue palivizumab and initiate appropriate supportive care and therapy (e.g., epinephrine). Palivizumab may be continued with caution based on clinical judgment in patients who experience a milder reaction.

Coagulation Disorders

Infants and children with thrombocytopenia or any coagulation disorder should be given IM injections with caution.

RSV Diagnostic Test Interference

May interfere with immunological-based RSV diagnostic tests such as some antigen detection-based assays and could lead to false-negative RSV diagnostic test results. Does not interfere with reverse transcriptase-polymerase chain reaction based assays.

Inhibits virus replication in cell culture, and therefore may also interfere with viral culture assays, which could lead to false-negative RSV diagnostic test results.

Specific Populations

Pregnancy

Not indicated for use in females of reproductive potential.

Lactation

Not indicated for use in females of reproductive potential.

Pediatric Use

Safety and efficacy not established in pediatric patients >24 months of age at the start of dosing.

Common Adverse Effects

Adverse effects (≥10%): fever, rash.

Injection site reactions (e.g., erythema, pain, induration/swelling, bruising) also reported.

Drug Interactions

Formal studies have not been conducted to evaluate potential interactions between palivizumab and other drugs.

Specific Drugs

Drug	Interaction
Bronchodilators	Not specifically studied, but no apparent increase in adverse effects when used concomitantly
Corticosteroids	Not specifically studied, but no apparent increase in adverse effects when used concomitantly
Vaccines	No evidence that palivizumab interferes with the immune response to vaccines; no apparent increase in adverse effects when given concomitantly with routine childhood vaccines

Palivizumab Pharmacokinetics

Absorption

Bioavailability

Well absorbed following IM injection in infants.

Plasma Concentrations

Concentrations >40 mcg/mL attained within 2 days after a single 15-mg/kg IM dose; peak concentrations attained within 5–7 days after a dose.

Monthly 15-mg/kg IM doses usually adequate to maintain trough serum concentrations exceeding the ideal target throughout the dosing period (except in children undergoing cardiopulmonary bypass). Lower doses (i.e., 3 or 10 mg/kg IV, 5 or 10 mg/kg IM) result in inadequate trough concentrations.

Surgical procedures involving cardiopulmonary bypass result in a mean 58% decrease in serum palivizumab concentrations.

Elimination

Half-life

Pediatric patients ≤24 months of age (including patients ≤6 months of age born at ≤35 weeks gestation): 19–27 days.

Stability

Storage

Parenteral

Injection

2–8°C in original container; do not freeze.

Actions and Spectrum

A highly selective antiviral agent active only against RSV.
Potent, RSV-neutralizing, monoclonal antibody that neutralizes and inhibits fusion of RSV, resulting in inhibition of viral replication.
Active against both major strains of RSV (subgroup A and B). In vivo neutralizing activity of the drug was confirmed in a clinical trial in RSV-infected pediatric patients as evidenced by lower recovery of RSV from lower respiratory tract secretions in palivizumab-treated patients compared with placebo recipients.

Advice to Patients

Inform the patient's caregiver of the symptoms of a hypersensitivity reaction (e.g., dyspnea, cyanosis, respiratory failure, urticaria, pruritus, angioedema, hypotonia, unresponsiveness). Advise the caregiver to seek medical attention immediately if the patient experiences a severe hypersensitivity reaction to palivizumab.
Advise the patient's caregiver that palivizumab should be administered by a healthcare provider once a month during the RSV season by IM injection and the importance of compliance with the full course of therapy.
Importance of informing clinician of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal products, and any concomitant illnesses.
Importance of advising caregivers of other important precautionary information. (See Cautions.)

Additional Information

The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer’s labeling should be consulted for more detailed information. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.