Lepirudin (injection)

Lepirudin (injection)
Adult Indications & Dosage
Pediatric Indications & Dosage
Contraindications
Warnings & Precautions
Adverse Reactions
Drug Interactions
Use in Specific Populations
Administration & Monitoring
Overdosage
Pharmacology
Clinical Studies
How Supplied
Images
Patient Counseling Information
Precautions with Alcohol
Brand Names
Look-Alike Names

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sheng Shi, M.D. [2]

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Overview

Lepirudin (injection) is a direct thrombin inhibitor that is FDA approved for the prophylaxis of anticoagulation. Common adverse reactions include Bleeding.

Adult Indications and Dosage

FDA-Labeled Indications and Dosage (Adult)

Coagulation

• Indication

• Refludan is indicated for anticoagulation in patients with heparin-induced thrombocytopenia (HIT) and associated thromboembolic disease in order to prevent further thromboembolic complications.

• Initial Dosage

• 0.4 mg/kg body weight (up to 110 kg) slowly intravenously (eg, over 15 to 20 seconds) as a bolus dose.

• CAUTION: Preparation of a Refludan bolus injection requires dilution following reconstitution in order to obtain the final concentration of 5 mg/mL.

• Followed by 0.15 mg/kg body weight (up to 110 kg)/hour as a continuous intravenous infusion for 2 to 10 days or longer if clinically needed.

• Normally the initial dosage depends on the patient's body weight.
• This is valid up to a body weight of 110 kg.
• In patients with a body weight exceeding 110 kg

• Initial dosage should not be increased beyond the 110 kg body weight dose (maximal initial bolus dose of 44 mg, maximal initial infusion dose of 16.5 mg/h; Initial Intravenous Bolus, Table 7 and DOSAGE AND ADMINISTRATION: Administration; Intravenous Infusion, Table 8).

• In general, therapy with REFLUDAN is monitored using the aPTT ratio (patient aPTT at a given time over an aPTT reference value, usually median of the laboratory normal range for aPTT, see DOSAGE AND ADMINISTRATION: Monitoring and Adjusting Therapy; Standard Recommendations). A patient baseline aPTT should be determined prior to initiation of therapy with REFLUDAN, since REFLUDAN should not be started in patients presenting with a baseline aPTT ratio of 2.5 or more, in order to avoid initial overdosing.

• Dose Modifications

• Any aPTT ratio out of the target range is to be confirmed at once before drawing conclusions with respect to dose modifications, unless there is a clinical need to react immediately.
• If the confirmed aPTT ratio is above the target range, the infusion should be stopped for two hours. At restart, the infusion rate should be decreased by 50% (no additional intravenous bolus should be administered). The aPTT ratio should be determined again 4 hours later.
• If the confirmed aPTT ratio is below the target range, the infusion rate should be increased in steps of 20%. The aPTT ratio should be determined again 4 hours later.
• In general, an infusion rate of 0.21 mg/kg/h should not be exceeded without checking for coagulation abnormalities which might be preventive of an appropriate aPTT response.

• Concomitant Use With Thrombolytic Therapy

Clinical trials in HIT patients have provided only limited information on the combined use of REFLUDAN and thrombolytic agents. The following dosage regimen of REFLUDAN was used in a total of 9 HIT patients in the HAT-1 and HAT-2 studies who presented with TECs at baseline and were started on both REFLUDAN and thrombolytic therapy (rt-PA, urokinase or streptokinase):

• Initial intravenous bolus: 0.2 mg/kg body weight. CAUTION: Preparation of a Refludan bolus injection requires dilution following reconstitution in order to obtain the final concentration of 5 mg/mL
• Continuous intravenous infusion: 0.1 mg/kg body weight/h

The number of patients receiving combined therapy was too small to identify differences in clinical outcome of patients who were started on both REFLUDAN and thrombolytic therapy as compared to those who were started on REFLUDAN alone. The combined incidences of death, limb amputation, or new TEC were 22.2% and 20.7%, respectively. While there was a 47% relative increase in the overall bleeding rate in patients who were started on both REFLUDAN and thrombolytic therapy (55.6% vs. 37.9%), there were no differences in the rates of serious bleeding events (fatal or life-threatening bleeds, bleeds that were permanently or significantly disabling, overt bleeds requiring transfusion of 2 or more units of packed red blood cells, bleeds necessitating surgical intervention, intracranial bleeds) between the groups (11.1% vs. 11.2%). Although no intracranial bleeding has been observed in any of these patients, there have been reports of intracranial bleeding in the presence or absence of concomitant thrombolytic therapy. (See WARNINGS and ADVERSE REACTIONS.) Special attention should be paid to the fact that thrombolytic agents per se may increase the aPTT ratio. Therefore, aPTT ratios with a given plasma level of lepirudin are usually higher in patients who receive concomitant thrombolysis than in those who do not (see also CLINICAL PHARMACOLOGY: Pharmacodynamic Properties).

Off-Label Use and Dosage (Adult)

Guideline-Supported Use

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

Non–Guideline-Supported Use

There is limited information regarding Off-Label Non–Guideline-Supported Use of Lepirudin in adult patients.

Pediatric Indications and Dosage

FDA-Labeled Indications and Dosage (Pediatric)

Safety and effectiveness in pediatric patients have not been established

Off-Label Use and Dosage (Pediatric)

Guideline-Supported Use

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

Non–Guideline-Supported Use

There is limited information regarding Off-Label Non–Guideline-Supported Use of Lepirudin in pediatric patients.

Contraindications

REFLUDAN is contraindicated in patients with known hypersensitivity to hirudins or to any of the components in REFLUDAN [lepirudin (rDNA) for injection].

Warnings

Hemorrhagic Events

As with other anticoagulants, hemorrhage can occur at any site in patients receiving REFLUDAN. An unexpected fall in hemoglobin, fall in blood pressure or any unexplained symptom should lead to consideration of a hemorrhagic event. While patients are being anticoagulated with REFLUDAN, the anticoagulation status should be monitored closely using an appropriate measure such as the aPTT (see ADVERSE REACTIONS and DOSAGE AND ADMINISTRATION: Monitoring section.) Intracranial bleeding following concomitant thrombolytic therapy with rt-PA or streptokinase may be life-threatening. There have been reports of intracranial bleeding with REFLUDAN in the absence of concomitant thrombolytic therapy (see ADVERSE REACTIONS.) For patients with increased risk of bleeding, a careful assessment weighing the risk of REFLUDAN administration vs its anticipated benefit has to be made by the treating physician: In particular, this includes the following conditions:

• Recent puncture of large vessels or organ biopsy
• Anomaly of vessels or organs
• Recent cerebrovascular accident, stroke, intracerebral surgery, or other neuraxail procedures
• Severe uncontrolled hypertension
• Bacterial endocarditis
• Advanced renal impairment (see also WARNINGS: Renal Impairment)
• Hemorrhagic diathesis
• Recent major surgery
• Recent major bleeding (eg, intracranial, gastrointestinal, intraocular, or pulmonary bleeding)
• Recent active peptic ulcer

Renal Impairment

With renal impairment, relative overdose might occur even with standard dosage regimen. Therefore, the bolus dose and the rate of infusion must be reduced in patients with known or suspected renal insufficiency CAUTION: Preparation of a Refludan bolus injection requires dilution following reconstitution in order to obtain the final concentration of 5 mg/mL. (see CLINICAL PHARMACOLOGY: Pharmacokinetic Properties and DOSAGE AND ADMINISTRATION: Monitoring and Adjusting Therapy; Use in Renal Impairment).

General

Antibodies

Formation of antihirudin antibodies was observed in about 40% of HIT patients treated with REFLUDAN. This may increase the anticoagulant effect of REFLUDAN possibly due to delayed renal elimination of active lepirudin-antihirudin complexes (see also PRECAUTIONS: Animal Pharmacology and Toxicology). Therefore, strict monitoring of aPTT is necessary also during prolonged therapy (see also PRECAUTIONS: Laboratory tests and DOSAGE AND ADMINISTRATION: Monitoring and Adjusting Therapy; Standard Recommendations). No evidence of neutralization of REFLUDAN or of allergic reactions associated with positive antibody test results was found.

Liver Injury

Serious liver injury (eg, liver cirrhosis) may enhance the anticoagulant effect of REFLUDAN due to coagulation defects secondary to reduced generation of vitamin K-dependent coagulation factors.

Reexposure

During the HAT-1 and HAT-2 studies, a total of 13 patients were reexposed to REFLUDAN. One of these patients experienced a mild allergic skin reaction during the second treatment cycle. In post marketing experience, anaphylaxis after reexposure has been reported. (see PRECAUTIONS—Allergic Reactions below and ADVERSE REACTIONS—Adverse Events from Post Marketing Reports.)

Allergic Reactions

There have been reports of allergic and hypersensitivity reactions including anaphylactic reactions. Serious anaphylactic reactions that have resulted in shock or death have been reported. These reactions have been reported during initial administration or upon second or subsequent reexposure(s).

Laboratory tests

In general, the dosage (infusion rate) should be adjusted according to the aPTT ratio (patient aPTT at a given time over an aPTT reference value, usually median of the laboratory normal range for aPTT); for full information, see DOSAGE AND ADMINISTRATION: Monitoring and Adjusting Therapy; Standard Recommendations. Other thrombin-dependent coagulation assays are changed by REFLUDAN (see also DESCRIPTION).

Adverse Reactions

Clinical Trials Experience

Adverse Events Reported in Clinical Trials in HIT Patients

The following safety information is based on all 198 patients treated with REFLUDAN in the HAT-1 and HAT-2 studies. The safety profile of 113 REFLUDAN patients from these studies who presented with TECs at baseline is compared to 91 such patients in the historical control.

Hemorrhagic Events

Bleeding was the most frequent adverse event observed in patients treated with REFLUDAN. Table 4 gives an overview of all hemorrhagic events which occurred in at least two patients.

This image is provided by the National Library of Medicine.

Other hemorrhagic events (hemoperitoneum, hemoptysis, liver bleeding, lung bleeding, mouth bleeding, retroperitoneal bleeding) each occurred in one individual among all 198 patients treated with REFLUDAN.

Nonhemorrhagic events

Table 5 gives an overview of the most frequently observed nonhemorrhagic events.

This image is provided by the National Library of Medicine.

Adverse Events Reported in Clinical Trials in Other Populations

The following safety information is based on a total of 2302 individuals who were treated with REFLUDAN in clinical pharmacology studies (n = 323) or for clinical indications other than HIT (n = 1979).

Intracranial Bleeding

Intracranial bleeding was the most serious adverse reaction found in populations other than HIT patients. It occurred in patients with acute myocardial infarction who were started on both REFLUDAN and thrombolytic therapy with rt-PA or streptokinase. The overall frequency of this potentially life-threatening complication among patients receiving both REFLUDAN and thrombolytic therapy was 0.6% (7 out of 1134 patients). Although no intracranial bleeding was observed in 1168 subjects or patients who did not receive concomitant thrombolysis, there have been post marketing reports of intracranial bleeding with REFLUDAN in the absence of concomitant thrombolytic therapy (seeADVERSE REACTIONS—Adverse Events from Post Marketing Reports and WARNINGS.)

Allergic Reactions

(See PRECAUTIONS.)

Allergic reactions or suspected allergic reactions in populations other than HIT patients include (in descending order of frequency*):

This image is provided by the National Library of Medicine.

• The CIOMS (Council for International Organization of Medical Sciences) III standard categories are used for classification of frequencies:

File:Lepirudin adverse 04.png

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About 53% (n = 46) of all allergic reactions or suspected allergic reactions occurred in patients who concomitantly received thrombolytic therapy (eg, streptokinase) for acute myocardial infarction and/or contrast media for coronary angiography.

Postmarketing Experience

Serious anaphylactic reactions that have resulted in shock or death have been reported. (See PRECAUTIONS.) Intracranial bleeding has been reported in patients treated with REFLUDAN with or without concomitant thrombolytic therapy. (SeeWARNINGS.) Although no intracranial bleeding was observed in Clinical Trials in those patients who did not receive concomitant thrombolytic therapy (see Adverse Events Reported in Clinical Trials in HIT Patients and Adverse Events Reported in Clinical Trials in Other Populations below), there have been post marketing reports of intracranial bleeding in patients who received REFLUDAN without concomitant thrombolytic therapy.

Drug Interactions

Concomitant treatment with thrombolytics (eg, rt-PA or streptokinase) may

• increase the risk of bleeding complications
• considerably enhance the effect of REFLUDAN on aPTT prolongation.

Use in Specific Populations

Pregnancy

Pregnancy Category (FDA): B Teratology studies with lepirudin performed in pregnant rats at intravenous doses up to 30 mg/kg/day (180 mg/m2/day, 1.2 times the recommended maximum human total daily dose based on body surface area) and in pregnant rabbits at intravenous doses up to 30 mg/kg/day (360 mg/m2/day, 2.4 times the recommended maximum human total daily dose based on body surface area) have revealed no evidence of harm to the fetus due to lepirudin. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Lepirudin (1 mg/kg) by intravenous administration crosses the placental barrier in pregnant rats. It is not known whether the drug crosses the placental barrier in humans. Following intravenous administration of lepirudin at 30 mg/kg/day (180 mg/m2/day, 1.2 times the recommended maximum human total daily dose based on body surface area) during organogenesis and perinatal-postnatal periods, pregnant rats showed an increased maternal mortality due to undetermined causes.
Pregnancy Category (AUS): There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Lepirudin (injection) in women who are pregnant.

Labor and Delivery

There is no FDA guidance on use of Lepirudin (injection) during labor and delivery.

Nursing Mothers

It is not known whether REFLUDAN is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from REFLUDAN, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established. In the HAT-2 study, two children, an 11-year-old girl and a 12-year-old boy, were treated with REFLUDAN. Both children presented with TECs at baseline. REFLUDAN doses given ranged from 0.15 mg/kg/h to 0.22 mg/kg/h for the girl, and from 0.1 mg/kg/h (in conjunction with urokinase) to 0.7 mg/kg/h for the boy. Treatment with REFLUDAN was completed after 8 and 58 days, respectively, without serious adverse events (Schiffmann 1997).

Geriatic Use

There is no FDA guidance on the use of Lepirudin (injection) in geriatric settings.

Gender

There is no FDA guidance on the use of Lepirudin (injection) with respect to specific gender populations.

Race

There is no FDA guidance on the use of Lepirudin (injection) with respect to specific racial populations.

Renal Impairment

As REFLUDAN is almost exclusively excreted in the kidneys (see also CLINICAL PHARMACOLOGY: Pharmacokinetic Properties), individual renal function should be considered prior to administration. In case of renal impairment, relative overdose might occur even with the standard dosage regimen. Therefore, the bolus dose and the infusion rate must be reduced in case of known or suspected renal insufficiency (creatinine clearance below 60 mL/min or serum creatinine above 1.5 mg/dL). CAUTION: Preparation of a Refludan bolus injection requires dilution following reconstitution in order to obtain the final concentration of 5 mg/mL. There is only limited information on the therapeutic use of REFLUDAN in HIT patients with significant renal impairment. The following dosage recommendations are mainly based on single-dose studies in a small number of patients with renal impairment. Therefore, these recommendations are only tentative and aPTT monitoring should be used along with monitoring of renal status. Dose adjustments should be based on creatinine clearance values, whenever available, as obtained from a reliable method (24 h urine sampling). If creatinine clearance is not available, the dose adjustments should be based on the serum creatinine. In all patients with renal insufficiency, the bolus dose is to be reduced to 0.2 mg/kg body weight. CAUTION: Preparation of a Refludan bolus injection requires dilution following reconstitution in order to obtain the final concentration of 5 mg/mL. The standard initial infusion rate given in DOSAGE AND ADMINISTRATION: Initial Dosage and DOSAGE AND ADMINISTRATION: Administration; Intravenous Infusion, Table 8 must be reduced according to the recommendations given in Table 6. Additional aPTT monitoring is highly recommended.

This image is provided by the National Library of Medicine.

Hepatic Impairment

There is no FDA guidance on the use of Lepirudin (injection) in patients with hepatic impairment.

Females of Reproductive Potential and Males

There is no FDA guidance on the use of Lepirudin (injection) in women of reproductive potentials and males.

Immunocompromised Patients

There is no FDA guidance one the use of Lepirudin (injection) in patients who are immunocompromised.

Administration and Monitoring

Administration

Directions on Preparation and Dilution REFLUDAN should not be mixed with other drugs except for Sterile Water for Injection USP, 0.9% Sodium Chloride Injection USP or 5% Dextrose Injection. Use REFLUDAN before the expiration date given on the carton and container. Reconstitution and further dilution are to be carried out under sterile conditions:

• For reconstitution, Sterile Water for Injection USP or 0.9% Sodium Chloride Injection USP are to be used.
• For further dilution, 0.9% Sodium Chloride Injection USP or 5% Dextrose Injection are suitable.
• For rapid, complete reconstitution, inject 1 mL of diluent into the vial and shake it gently. After reconstitution a clear, colorless solution is usually obtained in a few seconds, but definitely in less than 3 minutes. CAUTION: Preparation of a bolus injection requires dilution following reconstitution in order to obtain the final concentration of 5 mg/mL.
• Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. Do not use solutions that are cloudy or contain particles.
• The reconstituted solution is to be used immediately. It remains stable for up to 24 hours at room temperature (eg, during infusion).
• The preparation should be warmed to room temperature before administration.
• Discard any unused solution appropriately.

Initial Intravenous Bolus

CAUTION: Preparation of a Refludan bolus injection requires dilution following reconstitution in order to obtain the final concentration of 5 mg/mL. For intravenous bolus injection, use a solution with a concentration of 5 mg/mL. Preparation of a REFLUDAN solution with a concentration of 5 mg/mL:

• Reconstitute one vial (50 mg of lepirudin) with 1 mL of Sterile Water for Injection USP or 0.9% Sodium Chloride Injection USP. Reconstitution with 1 mL of diluent results in a concentration of 50 mg/mL. Once reconstituted, this product must be further diluted prior to administration.
• The final concentration of 5 mg/mL is obtained by transferring the contents of the vial into a sterile, single-use syringe (of at least 10 mL capacity) and diluting the solution to a total volume of 10 mL, using Sterile Water for injection USP, 0.9% Sodium Chloride Injection USP or 5% Dextrose Injection.
• The final solution is to be administered according to body weight (see Table 7 below and DOSAGE AND ADMINISTRATION: Initial Dosage).
• Intravenous injection of the bolus is to be carried out slowly (eg, over 15 to 20 seconds).

File:Lepirudin administration 01.png

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Intravenous Infusion

For continuous intravenous infusion, solutions with concentration of 0.2 mg/mL or 0.4 mg/mL may be used. Preparation of a REFLUDAN solution with a concentration of 0.2 or 0.4 mg/mL:

• Reconstitute two vials (each containing 50 mg of lepirudin) with 1 mL each using either Sterile Water for Injection USP or 0.9% Sodium Chloride Injection USP.
• The final concentrations of 0.2 mg/mL or 0.4 mg/mL are obtained by transferring the contents of both vials into an infusion bag containing 500 mL or 250 mL of 0.9% Sodium Chloride Injection USP or 5% Dextrose Injection.

The infusion rate [mL/h] is to be set according to body weight (see Table 8 below and DOSAGE AND ADMINISTRATION: Initial Dosage).

File:Lepirudin administration 02.png

This image is provided by the National Library of Medicine.

Monitoring

• In general, the dosage (infusion rate) should be adjusted according to the aPTT ratio (patient aPTT at a given time over an aPTT reference value, usually median of the laboratory normal range for aPTT).
• The target range for the aPTT ratio during treatment (therapeutic window) should be 1.5 to 2.5. Data from clinical trials in HIT patients suggest that with aPTT ratios higher than this target range, the risk of bleeding increases, while there is no incremental increase in clinical efficacy.
• As stated in DOSAGE AND ADMINISTRATION: Initial Dosage, REFLUDAN should not be started in patients presenting with a baseline aPTT ratio of 2.5 or more, in order to avoid initial overdosing.
• The first aPTT determination for monitoring treatment should be done 4 hours after start of the REFLUDAN infusion.
• Follow-up aPTT determinations are recommended at least once daily, as long as treatment with REFLUDAN is ongoing.
• More frequent aPTT monitoring is highly recommended in patients with renal impairment or serious liver injury (see DOSAGE AND ADMINISTRATION: Monitoring and Adjusting Therapy; Use in Renal Impairment) or with an increased risk of bleeding.

IV Compatibility

There is limited information about the IV Compatibility.

Overdosage

In case of overdose (eg, suggested by excessively high aPTT values) the risk of bleeding is increased. No specific antidote for REFLUDAN is available. If life-threatening bleeding occurs and excessive plasma levels of lepirudin are suspected, the following steps should be followed: Immediately STOP REFLUDAN administration Determine aPTT and other coagulation levels as appropriate Determine hemoglobin and prepare for blood transfusion Follow the current guidelines for treating patients with shock Individual clinical case reports and in vitro data suggest that either hemofiltration or hemodialysis (using high-flux dialysis membranes with a cutoff point of 50,000 daltons, eg, AN/69) may be useful in this situation. In studies in pigs, the application of von Willebrand Factor (vWF, 66 IU/kg body weight) markedly reduced the bleeding time. The clinical significance of this data is unknown.

Pharmacology

Mechanism of Action

FDA Package Insert for Abcixmab contains no information regarding mechanism of action.

Structure

REFLUDAN [lepirudin (rDNA) for injection] is a highly specific direct inhibitor of thrombin. Lepirudin, (chemical designation: [Leu1, Thr2]-63-desulfohirudin) is a recombinant hirudin derived from yeast cells. The polypeptide composed of 65 amino acids has a molecular weight of 6979.5 daltons. Natural hirudin is produced in trace amounts as a family of highly homologous isopolypeptides by the leech Hirudo medicinalis. The biosynthetic molecule (lepirudin) is identical to natural hirudin except for substitution of leucine for isoleucine at the N-terminal end of the molecule and the absence of a sulfate group on the tyrosine at position 63.

The activity of lepirudin is measured in a chromogenic assay. One antithrombin unit (ATU) is the amount of lepirudin that neutralizes one unit of World Health Organization preparation 89/588 of thrombin. The specific activity of lepirudin is approximately 16,000 ATU/mg. Its mode of action is independent of antithrombin III. Platelet factor 4 does not inhibit lepirudin. One molecule of lepirudin binds to one molecule of thrombin and thereby blocks the thrombogenic activity of thrombin. As a result, all thrombin-dependent coagulation assays are affected, eg, activated partial thromboplastin time (aPTT) and prothrombin time (PT /INR) values increase in a dose-dependent fashion (Roethig 1991).

REFLUDAN is supplied as a sterile, white, freeze-dried powder for injection or infusion and is freely soluble in Sterile Water for Injection USP or 0.9% Sodium Chloride Injection USP.

Each vial of REFLUDAN contains 50 mg lepirudin. Other ingredients are 40 mg mannitol and sodium hydroxide for adjustment of pH to approximately 7.

Pharmacodynamics

The pharmacodynamic effect of REFLUDAN on the proteolytic activity of thrombin was routinely assessed as an increase in aPTT. This was observed with increasing plasma concentrations of lepirudin, with no saturable effect up to the highest tested dose (0.5 mg/kg body weight intravenous bolus). Thrombin time (TT) frequently exceeded 200 seconds even at low plasma concentrations of lepirudin, which renders this test unsuitable for routine monitoring of REFLUDAN therapy. The pharmacodynamic response defined by the aPTT ratio (aPTT at a time after REFLUDAN administration over an aPTT reference value, usually median of the laboratory normal range for aPTT) depends on plasma drug levels which in turn depend on the individual patient's renal function (see CLINICAL PHARMACOLOGY:Pharmacokinetic Properties). For patients undergoing additional thrombolysis, elevated aPTT ratios were already observed at low lepirudin plasma concentrations, and further response to increasing plasma concentrations was relatively flat. In other populations, the response was steeper. At plasma concentrations of 1500 ng/mL, aPTT ratios were nearly 3.0 for healthy volunteers, 2.3 for patients with heparin-associated thrombocytopenia, and 2.1 for patients with deep venous thrombosis.

Pharmacokinetics

The pharmacokinetic properties of lepirudin following intravenous administration are well described by a two-compartment model. Distribution is essentially confined to extracellular fluids and is characterized by an initial half-life of approximately 10 minutes. Elimination follows a first-order process and is characterized by a terminal half-life of about 1.3 hours in young healthy volunteers. As the intravenous dose is increased over the range of 0.1 to 0.4 mg/kg, the maximum plasma concentration and the area-under-the-curve increase proportionally. Lepirudin is thought to be metabolized by release of amino acids via catabolic hydrolysis of the parent drug. However, conclusive data are not available. About 48% of the administration dose is excreted in the urine which consists of unchanged drug (35%) and other fragments of the parent drug. The systemic clearance of lepirudin is proportional to the glomerular filtration rate or creatinine clearance. Dose adjustment based on creatinine clearance is recommended (see DOSAGE AND ADMINISTRATION:Monitoring and Adjusting Therapy; Use in Renal Impairment). In patients with marked renal insufficiency (creatinine clearance below 15 mL/min), and on hemodialysis, elimination half-lives are prolonged up to 2 days. Lepirudin is thought to be metabolized by release of amino acids via catabolic hydrolysis of the parent drug. However, conclusive data are not available. About 48% of the administration dose is excreted in the urine which consists of unchanged drug (35%) and other fragments of the parent drug. The systemic clearance of lepirudin in women is about 25% lower than in men. In elderly patients, the systemic clearance of lepirudin is 20% lower than in younger patients. This may be explained by the lower creatinine clearance in elderly patients compared to younger patients. Table 1 summarizes systemic clearance (Cl) and volume of distribution at steady state (Vss) of lepirudin for various study populations.

This image is provided by the National Library of Medicine.

Nonclinical Toxicology

General Toxicity

Lepirudin caused bleeding in animal toxicity studies. Antibodies against hirudin which appeared in several monkeys treated with lepirudin resulted in a prolongation of the terminal half-life and an increase of AUC plasma values of lepirudin.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term animal studies to evaluate the potential for carcinogenesis have not been performed with lepirudin. Lepirudin was not genotoxic in the Ames test, the Chinese hamster cell (V79/HGPRT) forward mutation test, the A549 human cell line unscheduled DNA synthesis (UDS) test, the Chinese hamster V79 cell chromosome aberration test, or the mouse micronucleus test. An effect on fertility and reproductive performance of male and female rats was not seen with lepirudin at intravenous doses up to 30 mg/kg/day (180 mg/m2/day, 1.2 times the recommended maximum human total daily dose based on body surface area of 1.45m2 for a 50 kg subject).

Clinical Studies

Heparin-induced thrombocytopenia (HIT) is described as an allergy-like adverse reaction to heparin. It can be found in about 1% to 2% of patients treated with heparin for more than 4 days. The clinical picture of HIT is characterized by thrombocytopenia alone or in combination with thromboembolic complications (TECs). These complications comprise the entire spectrum of venous and arterial thromboembolism including deep venous thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke, and occlusion of limb arteries, which may ultimately result in necroses requiring amputation. Furthermore, there is evidence to suggest that warfarin-induced venous limb gangrene may be associated with HIT. Without further treatment, the mortality in HIT patients with new TECs is about 20% to 30% (Fondu 1995; Greinacher 1995; Warkentin, Chong, et al., Warkentin, Elavathil, et al. 1997). The conclusion that REFLUDAN is an effective treatment for HIT is based upon the data of two prospective, historically controlled clinical trials ("HAT-1" study and "HAT-2" study). The trials were comparable with regard to study design, primary and secondary objectives, and dosing regimens, as well as general study outline and organization. They both used the same historical control group for comparison. This historical control was mainly compiled from a recent retrospective registry of HIT patients. Overall, 198 (HAT-1: 82, HAT-2: 116) patients were treated with REFLUDAN and 182 historical control patients were treated with other therapies. All except 5 (HAT-1: 1, HAT-2: 4) prospective patients and all historical control patients were diagnosed with HIT using the heparin-induced platelet activation assay (HIPAA) or equivalent assays for testing. In total, 113 (HAT-1: 54, HAT-2: 59) prospective patients ("REFLUDAN") and 91 historical control patients ("historical control") presented with TECs at baseline (day of positive test result) and qualified for direct comparison of clinical endpoints. The gender distribution was found to be similar in REFLUDAN patients and historical control patients. Overall, REFLUDAN patients tended to be younger than historical control patients. Table 2 summarizes the demographic baseline characteristics of patients presenting with TECs at baseline.

How Supplied

REFLUDAN [lepirudin (rDNA) for injection] is supplied in boxes of 10 vials, each vial containing 50 mg lepirudin (NDC 50419-150-57).

Storage

Store unopened vials at 2 to 25°c (35.6 to 77°f). Use Refludan before the expiration date given on the carton and container. Once reconstituted, use refludan immediately.

Images

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Patient Counseling Information

FDA Package Insert for Lepirudin contains no information regarding Patient Counseling Information.

Precautions with Alcohol

Alcohol-Lepirudin interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

Brand Names

Refludan

Look-Alike Drug Names

There is limited information about the Look Alike Drug Names

Drug Shortage Status

Price

References

The contents of this FDA label are provided by the National Library of Medicine.

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{{#subobject:

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