Obiltoxaximab

FDA Drug Information • Also known as: Anthim

Brand Names: Anthim
Drug Class: Anthrax Protective Antigen-directed Antibody [EPC]
Route: INTRAVENOUS
Dosage Form: SOLUTION
Product Type: HUMAN PRESCRIPTION DRUG

⚠ Boxed Warning (Black Box)

WARNING: HYPERSENSITIVITY and ANAPHYLAXIS Hypersensitivity and anaphylaxis have been reported during the intravenous infusion of ANTHIM. Due to the risk of hypersensitivity and anaphylaxis, ANTHIM should be administered in monitored settings by personnel trained and equipped to manage anaphylaxis. Monitor individuals who receive ANTHIM closely for signs and symptoms of hypersensitivity reactions throughout the infusion and for a period of time after administration. Stop ANTHIM infusion immediately and treat appropriately if hypersensitivity or anaphylaxis occurs [see Indications and Usage ( 1.2 ), Dosage and Administration ( 2.4 ) and Warnings and Precautions ( 5.1 )]. WARNING: HYPERSENSITIVITY and ANAPHYLAXIS See full prescribing information for complete boxed warning. Hypersensitivity reactions, including anaphylaxis, have been reported during ANTHIM infusion ( 5.1 ) ANTHIM should be administered in monitored settings by personnel trained and equipped to manage anaphylaxis ( 1.2 , 2.4 , 5.1 ) Stop ANTHIM infusion immediately and treat appropriately if hypersensitivity or anaphylaxis occurs ( 2.4 , 5.1 )

Description

11 DESCRIPTION Obiltoxaximab is a chimeric IgG1 kappa monoclonal antibody (mAb) that binds the PA component of B. anthracis toxin. It has an approximate molecular weight of 148 kDa. ANTHIM injection is a sterile, preservative-free, clear to opalescent, colorless to pale yellow to pale brownish-yellow solution that may contain few translucent-to-white proteinaceous particulates. ANTHIM is supplied as 600 mg/6 mL in single-dose vials for intravenous infusion. Each mL contains 100 mg obiltoxaximab in L-histidine (6.2 mg), polysorbate 80 (0.1 mg), sorbitol (36 mg) with a pH of 5.5.

What Is Obiltoxaximab Used For?

1 INDICATIONS AND USAGE ANTHIM ® is a monoclonal antibody directed against the protective antigen of Bacillus anthracis . It is indicated in adult and pediatric patients for treatment of inhalational anthrax due to B. anthracis in combination with appropriate antibacterial drugs and, for prophylaxis of inhalational anthrax when alternative therapies are not available or are not appropriate. ( 1.1 ) Limitations of Use ANTHIM should only be used for prophylaxis when its benefit for prevention of inhalational anthrax outweighs the risk of hypersensitivity and anaphylaxis. ( 1.2 , 5.1 ) The effectiveness of ANTHIM is based solely on efficacy studies in animal models of inhalational anthrax. ( 1.2 , 14 ) There have been no studies of the safety or pharmacokinetics (PK) of ANTHIM in the pediatric population. Dosing in pediatric patients was derived using a population PK approach. ( 1.2 , 8.4 ) ANTHIM does not have direct antibacterial activity. ANTHIM should be used in combination with appropriate antibacterial drugs. ( 1.2 ) ANTHIM is not expected to cross the blood-brain barrier and does not prevent or treat meningitis. ( 1.2 ) 1.1 Inhalational Anthrax ANTHIM is indicated in adult and pediatric patients for the treatment of inhalational anthrax due to Bacillus anthracis in combination with appropriate antibacterial drugs. ANTHIM is indicated for prophylaxis of inhalational anthrax due to B. anthracis when alternative therapies are not available or not appropriate [see Indications and Usage ( 1.2 )] . 1.2 Limitations of Use ANTHIM should only be used for prophylaxis when its benefit for prevention of inhalational anthrax outweighs the risk of hypersensitivity and anaphylaxis [see Warnings and Precautions ( 5.1 )] . The effectiveness of ANTHIM is based solely on efficacy studies in animal models of inhalational anthrax. It is not ethical or feasible to conduct controlled clinical trials with intentional exposure of humans to anthrax [see Clinical Studies ( 14 )] . Safety and PK of ANTHIM have been studied in adult healthy volunteers. There have been no studies of safety or PK of ANTHIM in the pediatric population. A population PK approach was used to derive intravenous infusion dosing regimens that are predicted to provide pediatric patients with exposure comparable to the observed exposure in adults [see Use in Specific Populations ( 8.4 )] . ANTHIM binds to the protective antigen (PA) component of B. anthracis toxin; it does not have direct antibacterial activity. ANTHIM is not expected to cross the blood-brain barrier and does not prevent or treat meningitis. ANTHIM should be used in combination with appropriate antibacterial drugs.

Dosage and Administration

2 DOSAGE AND ADMINISTRATION Pre-medicate with diphenhydramine. ( 2.1 , 5.1 ) Recommended Dosage of ANTHIM: Adult Patients: 16 mg/kg. ( 2.1 ) Pediatric Patients: ( 2.2 ) ➢ Greater than 40 kg: 16 mg/kg ➢ Greater than 15 kg to 40 kg: 24 mg/kg ➢ Less than or equal to 15 kg: 32 mg/kg Dilute the injection in 0.9% Sodium Chloride Injection, USP, before administering as an intravenous (IV) infusion over 1 hour and 30 minutes. ( 2.3 ) Administer ANTHIM in a monitored setting equipped to manage anaphylaxis. ( 2.4 , 5.1 ) See Full Prescribing Information for instructions on preparation, dilution and administration of ANTHIM injection. ( 2.3 , 2.4 ) 2.1 Dosage for Adult Patients Pre-medicate with diphenhydramine prior to administering ANTHIM [see Warnings and Precautions ( 5.1 )] . Dilute the injection in 0.9% Sodium Chloride Injection, USP, before administering as an intravenous infusion [see Dosage and Administration ( 2.3 )] . The recommended dosage of ANTHIM in adult patients is a single dose of 16 mg/kg administered intravenously over 90 minutes (1 hour and 30 minutes) [see Dosage and Administration ( 2.4 )] . For adult patients weighing less than 40 kg, see Table 1 below. 2.2 Dosage for Pediatric Patients Pre-medicate with diphenhydramine prior to administering ANTHIM [see Warnings and Precautions ( 5.1 )]. Dilute the injection in 0.9% Sodium Chloride Injection, USP, before administering as an intravenous infusion [see Dosage and Administration ( 2.3 )]. The recommended dose for pediatric patients is based on weight as shown in Table 1 below. Table 1. Recommended Pediatric Dose of ANTHIM (weight-based dosing) Body Weight Dose Greater than 40 kg 16 mg/kg Greater than 15 kg to 40 kg 24 mg/kg Less than or equal to 15 kg 32 mg/kg Administer the recommended dose of ANTHIM intravenously over 90 minutes (1 hour and 30 minutes) [see Dosage and Administration ( 2.4 )] . There have been no studies of the safety or PK of ANTHIM conducted in the pediatric population. The dosing recommendations in Table 1 are derived from simulations using a population PK approach designed to match the observed adult exposure to ANTHIM at a 16 mg/kg dose [see Use in Specific Populations ( 8.4 )] . 2.3 Preparation and Dilution for Administration Important Preparation Instructions Keep vials in their cartons prior to preparation of an infusion solution to protect ANTHIM from light. ANTHIM vials contain no preservative. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Discard the vial if the solution is discolored or contains extraneous particles other than a few translucent-to- white, proteinaceous particles [see Description ( 11 )] . Do not shake the vial. Table 2. ANTHIM Dose, Total Infusion Volume and Infusion Rate by Body Weight Body Weight (weight-based dosing) Total Infusion Volume Infusion Rate Greater than 40 kg or adult (16 mg/kg) Greater than 40 kg 250 mL 167...

Side Effects (Adverse Reactions)

6 ADVERSE REACTIONS The following clinically important adverse reactions are described elsewhere in the labeling: Hypersensitivity and Anaphylaxis [see Warnings and Precautions ( 5.1 )]. Most frequently reported adverse reactions in healthy adult subjects (≥1.5%) were headache, pruritus, infections of the upper respiratory tract, cough, vessel puncture site bruise, infusion site swelling, nasal congestion, infusion site pain, urticaria and pain in extremity. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Elusys Therapeutics, Inc. at 1-844-808-0222 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of ANTHIM has been studied only in healthy volunteers. It has not been studied in patients with inhalational anthrax. The safety of ANTHIM was evaluated in 320 healthy subjects treated with one or more 16 mg/kg IV doses in three clinical studies. Study 1 was a placebo-controlled study evaluating a single dose of ANTHIM vs. placebo (210 subjects received ANTHIM, 70 received placebo). Study 2 was a repeat-dose study in which 70 subjects received the first dose, but 34 and 31 subjects received a second dose of ANTHIM in sequences A (2 weeks apart) and B (≥ 4 months apart), respectively. Study 3 was a drug interaction study of a single dose of ANTHIM with ciprofloxacin in 40 subjects (20 subjects received ANTHIM alone and 20 subjects received ANTHIM plus ciprofloxacin for 9 days). Subjects were 18 to 79 years of age, 54% were male, 70% Caucasian, 26% Black/African American, 2% American Indian/Alaska Native, 1% Asian and 10% Hispanic. Adverse Reactions Leading to Discontinuation of ANTHIM Infusion ANTHIM infusion was discontinued in 8/320 healthy subjects (2.5%) in clinical trials due to hypersensitivity reactions or anaphylaxis [see Warnings and Precautions ( 5.1 )] . Most Frequently Reported Adverse Reactions The most frequently reported adverse reactions were headache, pruritus, infections of the upper respiratory tract, cough, vessel puncture site bruise, infusion site swelling, urticaria, nasal congestion, infusion site pain, and pain in extremity. Table 3 shows the adverse reactions that occurred in ≥1.5% of healthy subjects receiving a single dose of ANTHIM (16 mg/kg IV) and more frequently than those receiving placebo. Table 3. Adverse Reactions Reported in ≥1.5% of Healthy Adult Subjects Exposed to a Single Dose of ANTHIM 16 mg/kg IV *Single-dose population: 210 subjects in study 1 plus 70 subjects in the first treatment period of study 2 plus 20 subjects in the ANTHIM alone treatment arm of study 3 Adverse Reactions Placebo N = 70 (%) Single Dose ANTHIM N = 300 * (%) Headache 4 (6%) 24 (8%) Pruritus 1 (1%) 11 (4%) Infections of the upper respiratory tract 2 (3%) 14 (5%) Cough 0 9 (3%) Vessel puncture site bruise 1 (1%) 8 (3%) Infusion site swelling 1 (1%) 8 (3%) Nasal congestion 1 (1%) 5 (2%) Infusion site pain 0 7 (2%) Urticaria 0 5 (2%) Pain in extremity 1 (1%) 5 (2%) Effect of Diphenhydramine on the Incidence of Adverse Reactions Overall in the single-dose population, subjects who received pre-medication with diphenhydramine were less likely to experience adverse reactions with administration of ANTHIM compared to those who did not (42% vs. 58% respectively). Specifically, the incidence of the following adverse reactions was lower in the subjects who received diphenhydramine prior to ANTHIM infusion compared to those who did not: headache (5% vs. 16%), cough (1% vs. 8%), rash (2% vs. 7%), pruritus (3% vs. 4%) throat irritation (0 vs. 3%), rhinorrhea (0 vs. 3%), and infusion site erythema (0% vs. 4%). Somnolence was only reported in subjects who were pretreated with diphenhydramine. Less Common Adverse Reactions...

Drug Interactions

7 DRUG INTERACTIONS 7.1 Ciprofloxacin Co-administration of 16 mg/kg ANTHIM intravenously with intravenous or oral ciprofloxacin in human subjects did not alter the PK of either ciprofloxacin or obiltoxaximab [see Clinical Pharmacology ( 12.3 )] .

Contraindications

4 CONTRAINDICATIONS None. None ( 4 )

Pregnancy and Breastfeeding

8.1 Pregnancy Risk Summary There are no data on the use of ANTHIM in pregnant women to inform on drug-associated risk. There are adverse effects on maternal and fetal outcomes associated with anthrax in pregnancy (see Clinical Considerations ). In pregnant rabbits, intravenous administration of obiltoxaximab during organogenesis was not associated with adverse developmental outcomes at up to 0.62 times the human systemic exposure at the maximum recommended adult dose (see Data ). The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk: Limited data in the form of case reports of anthrax infection in pregnant women indicate that maternal infection is associated with a high risk of maternal, fetal, and neonatal deaths, particularly in the absence of treatment. Data Animal Data: A study was conducted in pregnant, healthy, New Zealand White rabbits administered intravenous obiltoxaximab at dose levels of 16 or 32 mg/kg during organogenesis on Gestation Days 6, 10, 13 and 17. No maternal toxicity or adverse developmental outcomes were observed at the highest tested dose, 32 mg/kg. In those rabbits, mean maternal maximum plasma concentration (C max = 1180 mcg/mL) and mean maternal AUC inf (3220 mcg

day/mL) were approximately 3 times and 0.62 times the respective values for C max and AUC reported in clinical trial subjects at the maximum recommended adult dose of 16 mg/kg.

Overdosage

10 OVERDOSAGE There is no clinical experience with overdosage of ANTHIM. In case of overdosage, monitor patients for any signs or symptoms of adverse effects.

How Supplied

16 HOW SUPPLIED/STORAGE AND HANDLING ANTHIM injection is a sterile, preservative-free, clear to opalescent, colorless to pale yellow to pale brownish-yellow solution that may contain few translucent-to-white proteinaceous particulates in single-dose vials containing 600 mg/6 mL (100 mg/mL) and is available in the following packaging configuration: Carton: Contains one (1) single-dose vial of ANTHIM 600 mg/6 mL (NDC 69604-204-02). Store in refrigerator at 2°C to 8°C (36°F to 46°F) in original carton to protect from light. Do Not Freeze. Do Not Shake .

About This Information

This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.

What are side effects?

Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.

What are drug interactions?

Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.