Zamerovimab and Mazorelvimab Injection Application Scope

Indicated for passive post-exposure prophylaxis (PEP) of rabies in adults (aged ≥18 years) who have been exposed to rabies virus, particularly WHO/CDC Category III exposures (deep bites, multiple wounds, mucosal exposure, high-risk anatomical sites).

Used as part of rabies PEP together with active immunization (rabies vaccine).

Zamerovimab and Mazorelvimab Injection Characteristics

Ingredients: Zamerovimab and mazorelvimab
Properties: Clear, nearly colorless solution
Packaging Specification: 6 mg (2 mL) / vial and 15 mg (5 mL) / vial
Storage: Store and transport at 2–8°C (refrigerated), protected from light. Do not freeze
Expiry Date: 24 months (as stated in product information)
Executive Standard: Approved and regulated by local health authorities
Approval Number: Approved by China NMPA
Date of Revision: This is product-specific and should be checked on the latest package insert
Manufacturer: Synermore Biologics (Suzhou) Co., Ltd.

Guidelines for the Use of Zamerovimab and Mazorelvimab Injection

Dosage and Administration:
- Recommended Dose: 0.3 mg/kg (total dose = zamerovimab + mazorelvimab combined) administered once as an infiltration dose covering wound sites (local wound infiltration). This is a single adequate dose calculated by body weight (0.3 mg/kg).
- Administration:
  - Primary route: Local wound infiltration (infiltrate wounds thoroughly after prompt and thorough wound cleaning and debridement).
  - If residual volume remains after wound infiltration, administer remaining volume by intramuscular (IM) injection at a site distant from rabies vaccine administration.
  - If total calculated dose is insufficient to infiltrate all wounds, dilute with normal saline as needed to infiltrate all wounds.
  - Important: Vaccine and SYN023 must be administered at different anatomical sites with different syringes; do not use the same syringe for vaccine and mAb injection.
- Missed Dose: Missed dose concept is not applicable in the usual sense because SYN023 is a single-administration, weight-based passive immunotherapy given at the time of PEP initiation; if not given at time 0, it should be administered as soon as possible after exposure per clinical judgment. (Clinical guidance: administer promptly after exposure and after wound care.)
Adverse Reactions:
- Common Adverse Reactions:
  - Injection site reactions: swelling (very common), pain, erythema, pruritus.
  - Systemic: fever, headache, cough.
    (The manufacturer reports local reactions are common but overall reactogenicity compares favorably vs HRIG.)
- Serious Adverse Reactions: Serious hypersensitivity or anaphylactic reactions may occur in individuals with prior severe allergic history to components—contraindicated in known hypersensitivity. Clinical trials reported overall good safety; serious adverse events attributable to the product were rare. Always observe patients after parenteral antibody administration and be prepared to treat anaphylaxis.
Contraindications:
- Known hypersensitivity to zamerovimab, mazorelvimab, or any excipient in the formulation (e.g., polysorbate 80).
- History of severe allergic reactions to monoclonal antibody products may be considered a contraindication; follow local label and clinician judgment.
Precautions:
- Use only as part of a complete PEP regimen—must be combined with rabies vaccine (does not replace the vaccine).
- Inject at a different site from rabies vaccine and use separate syringes.
- For special populations (pregnancy, breastfeeding, pediatric patients <18 years, immunocompromised), follow local label/regulatory guidance—the current product indication per manufacturer is for adults; pediatric use and pregnant/breastfeeding data may be limited.
- Monitor for immediate hypersensitivity following injection.

Zamerovimab and Mazorelvimab Injection Interactions

No direct pharmacokinetic drug-drug interactions described in the product summary. Main practical interaction: do not mix or co-administer from the same syringe with rabies vaccine; administer at separate sites.
Concomitant immunoglobulin/antibody therapies may theoretically interact with vaccine immune responses—clinical trials indicate SYN023 does not impair subsequent vaccine-induced seroconversion, but follow label instructions regarding timing and coadministration.

Note:

If there is a new packaging for the drug, the new packaging shall prevail. The above information is sourced from DengYue Medicine.
This content is for reference only. Prescription drugs must be used under a doctor’s guidance and purchased from authorized sources.