Raxibacumab

Pregnancy Category: B

Lactation: Human immunoglobulins are excreted in human milk, published data suggest that neonatal consumption of human milk does not result in substantial absorption of these maternal immunoglobulins into circulation; exposure to breastfeeding infant unknown

Pregnancy Categories

A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA:Information not available.

Contraindications

None.1

Warnings/Precautions

Infusion Reactions

Infusion-related reactions were reported during administration of raxibacumab in clinical trials, including reports of rash, urticaria, and pruritus. If these reactions occur, slow or interrupt raxibacumab infusion and administer appropriate treatment based on severity of the reaction.1

Premedicate with diphenhydramine within 1 hour prior to administering raxibacumab to reduce the risk of infusion reactions.1

Specific Populations

Pregnancy category B.1

A single embryonic-fetal development study was conducted in pregnant, healthy New Zealand White rabbits administered 2 intravenous doses of raxibacumab up to 120 mg/kg (3 times the human dose on a mg/kg basis) on gestation days 7 and 14. No evidence of harm to the pregnant dam or the fetuses due to raxibacumab was observed. Cmaxvalues in rabbits after dosing with 120 mg/kg were 3,629 mcg/mL and 4,337 mcg/mL after the first and second doses of raxibacumab, respectively; these are more than 3 and 4 times the mean Cmax values in humans. Estimates of exposure (AUC) were not generated in the embryo-fetal rabbit study. No adequate and well-controlled studies in pregnant women were conducted. Because animal reproduction studies are not always predictive of human response, raxibacumab should be used during pregnancy only if clearly needed.1

Raxibacumab has not been evaluated in nursing women. Although human immunoglobulins are excreted in human milk, published data suggest that neonatal consumption of human milk does not result in substantial absorption of these maternal immunoglobulins into circulation. Inform a nursing woman that the effects of local gastrointestinal and systemic exposure to raxibacumab on a nursing infant are unknown.1

As in adults, the effectiveness of raxibacumab in pediatric patients is based solely on efficacy studies in animal models of inhalational anthrax. As exposure of healthy children to raxibacumab is not ethical, a population PK approach was used to derive dosing regimens that are predicted to provide pediatric patients with exposure comparable to the observed exposure in adults receiving 40 mg/kg. The dose for pediatric patients is based on weight.1

Safety or PK of raxibacumab have not been studied in the pediatric population.1

Clinical trials of raxibacumab did not include sufficient numbers of subjects aged 65 years and older to determine whether they respond differently from younger subjects. Of the total number of subjects in clinical trials of raxibacumab, 6.4% (21/326) were 65 years and older, while 1.5% (5/326) were 75 years and older. However, no alteration of dosing is needed for patients ≥65 years of age.1

Common Adverse Effects

Common adverse reactions in healthy adult subjects (≥1.5%) were rash, pain in extremity, pruritus, and somnolence.1

See FDA-approved patient labeling (Patient Information).

Efficacy Based on Animal Models

Inform patients that the efficacy of raxibacumab is based solely on efficacy studies demonstrating a survival benefit in animals and that the effectiveness of raxibacumab has not been tested in humans with anthrax. The safety of raxibacumab has been tested in healthy adults, but no safety data are available in children or pregnant women. Limited data are available in geriatric patients.1

Pregnancy and Nursing Mothers

Inform patients that raxibacumab has not been studied in pregnant women or nursing mothers so the effects of raxibacumab on pregnant women or nursing infants are not known. Instruct patients to tell their healthcare professional if they are pregnant, become pregnant, or are thinking about becoming pregnant. Instruct patients to tell their healthcare professional if they plan to breastfeed their infant.1

Infusion Reactions

Infusion-related reactions were reported during administration of raxibacumab in clinical trials, including reports of rash, urticaria, and pruritus.1

Prophylactic administration of diphenhydramine is recommended within 1 hour prior to administering raxibacumab. Diphenhydramine route of administration (oral or IV) should be based on the temporal proximity to the start of raxibacumab infusion.1

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.

Raxibacumab is stored in the US Strategic National Stockpile (SNS). FDA-approved vial and carton labeling and separate NDC numbers distinguish stockpile units of the drug from any units intended for commercial use.1 2