Idarucizumab

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# Overview
Idarucizumab is a humanized monoclonal antibody fragment (Fab) that is FDA approved for the treatment of patients treated with dabigatran when reversal of the anticoagulant effects of dabigatran is needed for emergency surgery/urgent procedures or in life-threatening or uncontrolled bleeding.   Common adverse reactions include headache (5%) in healthy volunteers and hypokalemia, delirium, constipation, pyrexia, and pneumonia (5%) in patients.

# Adult Indications and Dosage

## FDA-Labeled Indications and Dosage (Adult)
Idarucizumab is indicated in patients treated with dabigatran when reversal of the anticoagulant effects of this drug is needed:
- For emergency surgery/urgent procedures
- In life-threatening or uncontrolled bleeding
This indication is approved under accelerated approval based on a reduction in unbound dabigatran and normalization of coagulation parameters in healthy volunteers. Continued approval for this indication may be contingent upon the results of an ongoing cohort case series study.
- For intravenous use only.
- The recommended dose of Idarucizumab is 5 g, provided as two separate vials each containing 2.5 g/50 mL idarucizumab (see Figure 1).
- There is limited data to support administration of an additional 5 g of Idarucizumab.
- Restarting Antithrombotic Therapy
- Patients being treated with dabigatran therapy have underlying disease states that predispose them to thromboembolic events. Reversing dabigatran therapy exposes patients to the thrombotic risk of their underlying disease. To reduce this risk, resumption of anticoagulant therapy should be considered as soon as medically appropriate.
- Idarucizumab is a specific reversal agent for dabigatran, with no impact on the effect of other anticoagulant or antithrombotic therapies.
- Dabigatran treatment can be initiated 24 hours after administration of Idarucizumab.

## Off-Label Use and Dosage (Adult)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Idarucizumab in adult patients.

### NonGuideline-Supported Use
There is limited information regarding Off-Label NonGuideline-Supported Use of Idarucizumab in adult patients.

# Pediatric Indications and Dosage

## FDA-Labeled Indications and Dosage (Pediatric)
Safety and effectiveness have not been established in pediatric patients.

## Off-Label Use and Dosage (Pediatric)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Idarucizumab in pediatric patients.

### NonGuideline-Supported Use
There is limited information regarding Off-Label NonGuideline-Supported Use of Idarucizumab in pediatric patients.

# Contraindications
None

# Warnings
Patients being treated with dabigatran therapy have underlying disease states that predispose them to thromboembolic events. Reversing dabigatran therapy exposes patients to the thrombotic risk of their underlying disease. To reduce this risk, resumption of anticoagulant therapy should be considered as soon as medically appropriate.
In a limited number of patients in the clinical program, between 12 and 24 hours after administration of 5 g idarucizumab, elevated coagulation parameters (e.g., activated partial thromboplastin time (aPTT) or ecarin clotting time (ECT)) have been observed.
If reappearance of clinically relevant bleeding together with elevated coagulation parameters is observed after administration of 5 g Idarucizumab, administration of an additional 5 g dose of Idarucizumab may be considered. Similarly, patients who require a second emergency surgery/urgent procedure and have elevated coagulation parameters may receive an additional 5 g dose of Idarucizumab.
The safety and effectiveness of repeat treatment with Idarucizumab have not been established.
There is insufficient clinical experience with Idarucizumab in patients to evaluate risk of hypersensitivity to idarucizumab. In clinical studies adverse events possibly indicative of hypersensitivity reactions where a possible relationship could not be excluded were reported. The risk of using Idarucizumab in patients with known hypersensitivity (e.g., anaphylactoid reaction) to idarucizumab or to any of the excipients needs to be weighed cautiously against the potential benefit of such an emergency treatment. If an anaphylactic reaction or other serious allergic reaction occurs, immediately discontinue administration of Idarucizumab and institute appropriate treatment.
In patients with the condition of hereditary fructose intolerance who have received parenteral administration of sorbitol, serious adverse reactions, including fatal reactions, have been reported. Reactions have included hypoglycemia, hypophosphatemia, metabolic acidosis, increase in uric acid, acute liver failure with breakdown of excretory and synthetic function.
The recommended dose of Idarucizumab contains 4 g sorbitol as an excipient. When prescribing Idarucizumab to patients with hereditary fructose intolerance consider the combined daily metabolic load of sorbitol/fructose from all sources, including Idarucizumab and other drugs containing sorbitol. The minimum amount of sorbitol at which serious adverse reactions may occur in these patients is not known.

# Adverse Reactions

## Clinical Trials Experience
The following serious adverse reactions are described in more detail elsewhere in the labeling:
- Thromboembolic Risk
- Hypersensitivity Reactions
- Risks of Serious Adverse Reactions in Patients with Hereditary Fructose Intolerance due to Sorbitol Excipient
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 clinical practice.
Three clinical trials in healthy volunteers have been completed, in which 224 subjects were treated with idarucizumab. In these trials during the treatment period the overall frequency of adverse events was similar between idarucizumab-treated subjects (55/224, 25%) and placebo-treated subjects (26/105, 25%). Among those subjects treated with idarucizumab, adverse reactions reported in greater than or equal to 5% of subjects was headache (12/224, 5%).
In the interim analysis of the RE-VERSE ADTM (RE-VERSal Effects of idarucizumab on Active Dabigatran) trial, a total of 123 dabigatran-treated patients were administered idarucizumab either because they required an emergency surgery or urgent procedure, or because they presented with life-threatening or uncontrolled bleeding. Adverse reactions reported in greater than or equal to 5% of patients were: hypokalemia (9/123, 7%), delirium (9/123, 7%), constipation (8/123, 7%), pyrexia (7/123, 6%), pneumonia (7/123, 6%). Of the total, 26 patients died, 11 within the first day after idarucizumab dosing; each of these deaths could be attributed either as a complication of the index event or associated with co-morbidities.
- Thromboembolic Events
- In the interim analysis of the RE-VERSE AD trial, 5 of 123 patients reported thrombotic events, 1 patient 2 days after treatment with idarucizumab and 4 patients 7 days or more after treatment with idarucizumab. None of these patients were on antithrombotic therapy at the time of the event, and in each of these cases, the thrombotic event could be attributed to the underlying medical condition of the patient.
- Hypersensitivity
- Pyrexia, bronchospasm, hyperventilation, rash, and pruritus have been reported in clinical trials with idarucizumab.
As with all proteins there is a potential for immunogenicity with idarucizumab. Using an electro-chemiluminescence (ECL) based assay, plasma samples from 283 subjects (224 treated with idarucizumab) were tested for antibodies cross-reacting with idarucizumab. Pre-existing antibodies with cross-reactivity to idarucizumab were detected in approximately 13% (36/283) of the subjects. The majority of pre-existing antibodies were shown to have low titers. No impact on the pharmacokinetics or the reversal effect of idarucizumab or hypersensitivity reactions were observed in these subjects. Treatment-emergent possibly persisting anti-idarucizumab antibodies with low titers were observed in 4% (9/224) of the subjects treated with idarucizumab.
The epitope specificity of antibodies to idarucizumab was characterized using probe molecules. For pre-existing antibodies, 97% (35/36) had specificity for the C-terminus, a region of idarucizumab to which dabigatran does not bind. For treatment emergent possibly persisting antibodies, 56% (5/9) had specificity for the C-terminus, 22% (2/9) had specificity for the variable region, 11% (1/9) had mixed specificity and 11% (1/9) was indeterminate.
Detection of antibody formation is dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody positivity may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications and underlying disease. For these reasons, comparison of the incidence of antibodies to idarucizumab with the incidence of antibodies to other products may be misleading.

## Postmarketing Experience
There is limited information regarding Idarucizumab Postmarketing Experience in the drug label.

# Drug Interactions
There is limited information regarding Idarucizumab Drug Interactions in the drug label.

# Use in Specific Populations

### Pregnancy
Pregnancy Category (FDA): N
- Risk Summary
- There are no adequate and well-controlled studies of Idarucizumab in pregnant women to inform on associated risks. Animal reproductive and development studies have not been conducted with idarucizumab. It is also not known whether Idarucizumab can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Idarucizumab should be given to a pregnant woman only if clearly needed.
- The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.
Pregnancy Category (AUS): 
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Idarucizumab in women who are pregnant.

### Labor and Delivery
Idarucizumab has not been studied for use during labor and delivery. Safety and effectiveness of Idarucizumab during labor and delivery have not been studied in clinical trials.

### Nursing Mothers
There are no data on the effects of Idarucizumab on the breastfed child or on milk production.
It is not known whether idarucizumab is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Idarucizumab is administered to a nursing woman.
The developmental and health benefits of breastfeeding should be considered along with the mothers clinical need for Idarucizumab and any potential adverse effects on the breastfed child from Idarucizumab or from the underlying maternal condition.

### Pediatric Use
Safety and effectiveness have not been established in pediatric patients.

### Geriatic Use
A total of 111 (90%) patients treated with idarucizumab in the case series trial were 65 years of age and older, and 74 (60%) were 75 years of age and older. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

### Gender
There is no FDA guidance on the use of Idarucizumab with respect to specific gender populations.

### Race
There is no FDA guidance on the use of Idarucizumab with respect to specific racial populations.

### Renal Impairment
Renal impairment did not impact the reversal effect of idarucizumab. No dose adjustment is required in renally impaired patients.

### Hepatic Impairment
No formal studies of Idarucizumab in patients with hepatic impairment have been conducted.

### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Idarucizumab in women of reproductive potentials and males.

### Immunocompromised Patients
There is no FDA guidance one the use of Idarucizumab in patients who are immunocompromised.

# Administration and Monitoring

### Administration
- Preparation
- Ensure aseptic handling when preparing the infusion.
- Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
- Once solution has been removed from the vial, administration should begin promptly or within 1 hour.
- Administration
- Do not mix with other medicinal products. Use aseptic technique when administering Idarucizumab.
- Intravenously administer the dose of 5 g (2 vials, each contains 2.5 g) as
- Two consecutive infusions (see Figure 2) or
- Bolus injection by injecting both vials consecutively one after another via syringe (see Figure 3).
- A pre-existing intravenous line may be used for administration of Idarucizumab. The line must be flushed with sterile 0.9% Sodium Chloride Injection, USP solution prior to infusion. No other infusion should be administered in parallel via the same intravenous access.
- Idarucizumab treatment can be used in conjunction with standard supportive measures, which should be considered as medically appropriate.

### Monitoring
There is limited information regarding Idarucizumab Monitoring in the drug label.

# IV Compatibility
There is limited information regarding the compatibility of Idarucizumab and IV administrations.

# Overdosage
There is limited information regarding Idarucizumab overdosage.  If you suspect drug poisoning or overdose, please contact the National Poison Help hotline (1-800-222-1222) immediately.

# Pharmacology

## Mechanism of Action
Idarucizumab is a specific reversal agent for dabigatran. It is a humanized monoclonal antibody fragment (Fab) that binds to dabigatran and its acylglucuronide metabolites with higher affinity than the binding affinity of dabigatran to thrombin, neutralizing their anticoagulant effect.

## Structure
Idarucizumab is a humanized monoclonal antibody fragment (Fab) derived from an IgG1 isotype molecule, whose target is the direct thrombin inhibitor dabigatran. Using recombinant expression technology, idarucizumab is produced in a well characterized recombinant (mammalian) CHO cell line and is purified using standard technology. Idarucizumab is composed of a light chain of 219 amino acids and a heavy chain fragment of 225 amino acids, covalently linked together by one disulfide bond between cysteine 225 of the heavy chain fragment and cysteine 219 of the light chain, and has an estimated molecular mass of approximately 47,766 Daltons.
Idarucizumab is a sterile, preservative-free, colorless to slightly yellow, clear to slightly opalescent solution for intravenous administration. Idarucizumab is supplied in 2 single-use vials, each containing 2.5 g of idarucizumab in 50 mL formulated as a buffered, isotonic, solution containing acetic acid glacial (10.05 mg), polysorbate 20 (10 mg), sodium acetate trihydrate (147.35 mg), sorbitol (2004.20 mg), and water for injection with an osmolality of 270-330 mOsm/kg and a pH of 5.3-5.7.

## Pharmacodynamics
In healthy subjects aged 45 to 64 years, the plasma concentrations of unbound dabigatran were reduced to below the lower limit of quantification immediately after the administration of 5 g idarucizumab. Subjects diluted thrombin time (dTT), ECT, aPTT, thrombin time (TT), and activated clotting time (ACT) parameters returned to baseline levels (see Figure 4 and Figure 5). This reduction of dabigatran plasma concentration was observed over the entire observation period of at least 24 hours. Similar findings were also observed in elderly subjects (aged 65 to 80 years) as well as subjects with mild and moderate renal impairment.
In a limited number of patients, re-distribution of dabigatran from the periphery to plasma led to re-elevation of dTT, ECT, aPTT, and TT.
Re-dosing with 2.5 g idarucizumab in 6 healthy subjects aged 45-64 years at 2 months after first infusion revealed no differences in safety and no indication of allergic reactions.
No changes in the pharmacokinetics or pharmacodynamics of dabigatran were noted upon re-initiation 24 hours after the administration of idarucizumab.
- Thrombin Generation Parameters
- Idarucizumab alone has shown no procoagulant effect measured as endogenous thrombin potential (ETP).
- Cardiac Electrophysiology
- Clinical trials with idarucizumab in healthy subjects measured heart rate and electrocardiogram (ECG) parameters (waveform morphology, P wave duration, and PR, QRS, QT, and QTc intervals). There were no clinically relevant abnormal findings related to ECG.
- Drug Interactions
- In vitro Assessment of Drug Interactions
- In vitro data suggest that the inhibition of dabigatran by idarucizumab is not affected by coagulation factor concentrates .
- Assessment of Drug Interactions in Animal Studies
- The potential effect of the binding of idarucizumab to dabigatran in the presence of volume replacement agents (e.g., crystalloids, colloids, and retransfusion of washed red blood cells) was investigated in swine. The results of this study suggest that neutralization of dabigatran anticoagulant activity is not influenced by 50% hemodilution with routinely used volume replacement strategies.

## Pharmacokinetics
There were no obvious differences in the idarucizumab plasma concentration time profiles when idarucizumab was administered alone or after pretreatment with dabigatran. A dose-dependent increase in the fraction of unchanged idarucizumab excreted in urine was observed.
- Distribution
- Idarucizumab exhibited multiphasic disposition kinetics and limited extravascular distribution. Following the intravenous infusion of a 5 g dose, the geometric mean volume of distribution at steady state (Vss) was 8.9 L (geometric coefficient of variation (gCV 24.8%)).
- Elimination
- Idarucizumab was rapidly eliminated with a total clearance of 47.0 mL/min (gCV 18.4%), an initial half-life of 47 minutes (gCV 11.4%), and a terminal half-life of 10.3 h (gCV 18.9%). After intravenous administration of 5 g idarucizumab, 32.1% (gCV 60.0%) of the dose was recovered in urine within a collection period of 6 hours and less than 1% in the following 18 hours. The remaining part of the dose is assumed to be eliminated via protein catabolism, mainly in the kidney.
- Metabolism
- Several pathways have been described that may contribute to the metabolism of antibodies. All of these pathways involve biodegradation of the antibody to smaller molecules, i.e., small peptides or amino acids which are then reabsorbed and incorporated in the general protein synthesis.
- Specific Populations
- Age, Sex, Race and Body Weight
- Age, sex, race (Caucasian vs Asian) and body weight had no clinically important effect on systemic exposure of idarucizumab based on population pharmacokinetic analyses in a healthy volunteer cohort of 201 males and 19 females.
- Renal Impairment
- Idarucizumab has been studied in 12 subjects with mild renal impairment (creatinine clearance 60 to <90 mL/min, by Cockcroft-Gault equation) and 6 subjects with moderate impairment (creatinine clearance 30 to <60 mL/min). Compared to healthy subjects, the total clearance was reduced, leading to an increase in idarucizumabs area under the curve (AUC) by 43.5% and 83.5% in mild and moderate renal impairment, respectively.

## Nonclinical Toxicology
No carcinogenicity or genotoxicity studies have been conducted with idarucizumab. No animal studies have been performed to evaluate the potential effects of idarucizumab on fertility in males or females or on reproduction and development.

# Clinical Studies
The safety and effectiveness of Idarucizumab has been investigated in pharmacokinetic/pharmacodynamic trials with healthy volunteers and in an ongoing single cohort case series trial with dabigatran-treated patients who have life-threatening or uncontrolled bleeding, or who require emergency surgery or urgent procedure (RE-VERSE AD).
- Healthy Volunteers
- Three randomized, placebo-controlled trials in a total of 283 subjects assessed the safety, dose-response, and effect of idarucizumab on reducing unbound dabigatran and coagulation parameters. Of the 283 subjects, 224 received at least one dose of idarucizumab. These trials included 19 females and 30 subjects aged 65 years or older (median age 36 years).
- The tables below summarize the idarucizumab effect on coagulation parameters dTT, aPTT, ECT, TT, and ACT over time for 14 subjects treated in one of the healthy volunteer trials. Fourteen subjects received dabigatran 220 mg orally twice daily for three days and an additional single 220 mg dose of dabigatran on day four, two hours before receiving idarucizumab. Idarucizumab was administered as one 5 g intravenous infusion over five minutes. Table 1 shows the results of the idarucizumab treatment group and Table 2 shows the results of the placebo treatment group.
The effect of idarucizumab on reducing unbound dabigatran in healthy volunteers is summarized in Pharmacodynamics section.
- RE-VERSE AD Patient Experience
- In an ongoing single cohort case series trial, 5 g idarucizumab was administered to patients treated with dabigatran who presented with dabigatran-related life-threatening or uncontrolled bleeding (Group A) or who required emergency surgery or urgent procedures (Group B). The primary endpoint was the maximum percentage reversal of the pharmacodynamic anticoagulant effect of dabigatran within 4 hours after the administration of idarucizumab, based on central laboratory determination of dTT or ECT.
- An interim analysis of the ongoing single cohort case series trial included data for 123 patients: 66 patients with serious bleeding (Group A) and 57 requiring an urgent procedure (Group B). Approximately half of the patients in each group were male. The median age was 77 years and the median creatinine clearance was 55 mL/min. Approximately 67% of patients in Group A and 63% of patients in Group B had been treated with dabigatran 110 mg BID. Results of central laboratory evaluations were available for a subset of 90 patients (51 in Group A, 39 in Group B).
- Among the 90 patients with available data, the median maximum reversal of the pharmacodynamic anticoagulant effect of dabigatran as measured by ECT or dTT in the first 4 hours after administration of 5 g idarucizumab was 100%, with most patients (>89%) achieving complete reversal. Reversal of the pharmacodynamics effects was evident immediately after administration. Results for Groups A and B were similar. In a limited number of patients, between 12 and 24 hours after administration of 5 g idarucizumab, elevated coagulation parameters (e.g., aPTT or ECT) have been observed. ECT measures over the 24-hour observation time are shown in Figure 6.
Activated partial thromboplastin time (aPTT) showed similar results to ECT (see Figure 7).

# How Supplied
- Idarucizumab is a sterile, preservative-free, colorless to slightly yellow, clear to slightly opalescent solution supplied as 2 single-use vials each containing 2.5 g/50 mL of idarucizumab.
- NDC number 0597-0197-05: Carton containing two 2.5 g/50 mL vials.

## Storage
- Store Idarucizumab vials in the refrigerator at 2oC to 8oC (36oF to 46oF). Do not freeze. Do not shake.
- Prior to use, the unopened vial may be kept at room temperature 25C (77F) for up to 48 hours, if stored in the original package in order to protect from light, or up to 6 hours when exposed to light.

# Images

## Drug Images

## Package and Label Display Panel

# Patient Counseling Information
- Thromboembolic Risk
- Inform patients that reversing dabigatran therapy exposes them to the thromboembolic risk of their underlying disease. To reduce this risk, resumption of anticoagulant therapy should be considered as soon as the patient is sufficiently stable.
- Recurrence of Bleeding
- Inform patients to get immediate medical attention for any signs or symptoms of bleeding.
- Hypersensitivity Reactions
- Inform patients of signs and symptoms of allergic hypersensitivity reactions such as anaphylactoid reactions that may be experienced during or after injection of Idarucizumab.
- Risk of Serious Adverse Reactions in Patients with Hereditary Fructose Intolerance due to Sorbitol Excipient
- Inform patients with hereditary fructose intolerance (HFI) that Idarucizumab contains sorbitol. Parenteral administration of sorbitol in patients who have HFI has been associated with reports of hypoglycemia, hypophosphatemia, metabolic acidosis, increase in uric acid, acute liver failure with breakdown of excretory and synthetic function, and death and may occur during or after injection of Idarucizumab.

# Precautions with Alcohol
Alcohol-Idarucizumab interaction has not been established. Talk to your doctor regarding the effects of taking alcohol with this medication.

# Brand Names
PRAXBIND

# Look-Alike Drug Names
There is limited information regarding Idarucizumab Look-Alike Drug Names in the drug label.

# Drug Shortage Status

# Price