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{{drugbox
{{DrugProjectFormSinglePage
| IUPAC_name =  
|authorTag={{MN}}
| image =  
|genericName=Defibrotide
| CAS_number = 83712-60-1
|aOrAn=an
| ATC_prefix =
|drugClass=[[oligonucleotide]] mixture with [[profibrinolytic]] properties
| ATC_suffix =  
|indicationType=treatment
|indication=adult and pediatric patients with [[hepatic veno-occlusive disease]] (VOD), with renal or pulmonary dysfunction following [[Hematopoietic stem cell transplantation|hematopoietic stem-cell transplantation]] (HSCT)
|adverseReactions=[[hypotension]], [[diarrhea]], [[vomiting]], [[nausea]], and [[epistaxis]] (≥10%)
|fdaLIADAdult=======Indications======
Defibrotide is indicated for the treatment of adult and pediatric patients with [[hepatic veno-occlusive disease]] (VOD), also known as [[sinusoidal obstruction syndrome]] (SOS), with renal or pulmonary dysfunction following [[Hematopoietic stem cell transplantation|hematopoietic stem-cell transplantation]] (HSCT).
 
======Dosage======
The recommended dosage of Defibrotide for adult and pediatric patients is 6.25 mg/kg every 6 hours given as a 2‑hour [[intravenous infusion]]. The dose should be based on patient’s baseline body weight, defined as the patient’s weight prior to the preparative regimen for [[HSCT]].
 
Administer Defibrotide for a minimum of 21 days. If after 21 days signs and symptoms of hepatic VOD have not resolved, continue Defibrotide until resolution of VOD or up to a maximum of 60 days.
 
:*Treatment Modification
Treatment modification, including temporary or permanent discontinuation of Defibrotide, should follow the recommendations in Table 1.
 
:*'''Table 1: Treatment Modifications for Toxicity or Invasive Procedures'''
[[File:table1_def.png|thumb|none|400px|This image is provided by the National Library of Medicine.]]
<SMALL>DEFITELIO: Defibrotide's Brand name</SMALL>
|fdaLIADPed=======Indications======
Defibrotide is indicated for the treatment of adult and pediatric patients with [[hepatic veno-occlusive disease]] (VOD), also known as [[sinusoidal obstruction syndrome]] (SOS), with renal or pulmonary dysfunction following [[Hematopoietic stem cell transplantation|hematopoietic stem-cell transplantation]] (HSCT).
 
======Dosage======
The recommended dosage of Defibrotide for adult and pediatric patients is 6.25 mg/kg every 6 hours given as a 2‑hour [[intravenous infusion]]. The dose should be based on patient’s baseline body weight, defined as the patient’s weight prior to the preparative regimen for [[HSCT]].
 
Administer Defibrotide for a minimum of 21 days. If after 21 days signs and symptoms of hepatic VOD have not resolved, continue Defibrotide until resolution of VOD or up to a maximum of 60 days.
 
:*Treatment Modification
Treatment modification, including temporary or permanent discontinuation of Defibrotide, should follow the recommendations in Table 1.
|contraindications=The use of Defibrotide is contraindicated in the following conditions:
 
:Concomitant administration with systemic [[anticoagulant]] or [[fibrinolytic]] therapy.
:Known [[hypersensitivity]] to Defibrotide or to any of its excipients.
|warnings=:*'''[[Hemorrhage]]'''
Defibrotide increased the activity of [[fibrinolytic]] [[enzymes]] [[in vitro]], and it may increase the risk of bleeding in patients with [[VOD]] after hematopoietic stem-cell transplantation ([[HSCT]]). Do not initiate Defibrotide in patients with active bleeding. Monitor patients for signs of bleeding. If patients on Defibrotide develop bleeding, discontinue Defibrotide, treat the underlying cause, and provide [[supportive care]] until the bleeding has stopped.
 
Concomitant use of Defibrotide and a systemic anticoagulant or fibrinolytic therapy (not including use for routine maintenance or reopening of [[central venous line]]s) may increase the risk of bleeding. Discontinue anticoagulants and fibrinolytic agents prior to Defibrotide treatment, and consider delaying the start of Defibrotide administration until the effects of the anticoagulant have abated.
 
:*'''[[Hypersensitivity]] Reactions'''
Hypersensitivity reactions have occurred in less than 2% of patients treated with Defibrotide. These reactions include [[rash]], [[urticaria]] and [[angioedema]]. One case of an [[anaphylactic]] reaction was reported in a patient who had previously received Defibrotide. Monitor patients for hypersensitivity reactions, especially if there is a history of previous exposure. If a severe hypersensitivity reaction occurs, discontinue Defibrotide, treat according to the standard of care, and monitor until symptoms resolve.
|clinicalTrials=The following adverse reactions are discussed in greater detail in other sections of the labeling:
 
:*Hemorrhage
:*Hypersensitivity Reactions
 
Because [[clinical trial]]s 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 Defibrotide was determined in 176 adult and pediatric patients with hepatic [[VOD]] with pulmonary and/or renal dysfunction following [[HSCT]] who were treated with Defibrotide 6.25 mg/kg every 6 hours. Patients were excluded from these trials if at time of study entry they had significant acute bleeding, active grades B-D graft-versus-host disease, or a requirement for multiple [[vasopressors]] to provide [[blood pressure]] support. For the purposes of adverse event recording in the clinical trials, events were not required to be reported if they were related to the hepatic [[VOD]], or if they were expected to occur after hematopoietic stem-cell transplantation ([[HSCT]]), unless they were serious or Grade 4-5.
 
The median age of the safety population was 25 years (range: 1 month to 72 years), and 63% were ≥17 years of age. A total of 60% of patients were male, 78% were white, 89% had undergone [[allogeneic]] [[HSCT]], and the underlying diagnosis was [[acute leukemia]] for 43%. At study entry, 13% were dialysis dependent and 18% were ventilator dependent. Defibrotide was administered for a median of 21 days (range: 1 to 83 days).
 
Information about adverse reactions resulting in permanent discontinuation of Defibrotide was available for 102 patients, and 35 (34%) of these patients had an adverse reaction with permanent discontinuation. Adverse reactions leading to permanent discontinuation included [[pulmonary alveolar hemorrhage]] in 5 (5%) patients; [[pulmonary hemorrhage]], [[hypotension]], [[catheter site hemorrhage]], and [[multi-organ failure]], each in 3 (3%) patients; and [[cerebral hemorrhage]] and [[sepsis]], each in 2 (2%) patients.
 
Information about adverse reactions of any grade was available for all 176 patients. The most common adverse reactions (incidence ≥10% and independent of causality) were [[hypotension]], [[diarrhea]], [[vomiting]], [[nausea]], and [[epistaxis]]. The most common serious adverse reactions (incidence ≥5% and independent of causality) were [[hypotension]] (11%) and [[pulmonary alveolar hemorrhage]] (7%). Hemorrhage events of any type and any grade were reported for 104 (59%) of the patients, and the events were grade 4-5 in 35 (20%).
 
Table 2 presents adverse reactions independent of causality ≥10% any grade or Grade 4/5 ≥2% reported in patients treated with Defibrotide.
 
:*'''Table 2: Adverse Reactions(a) ≥10% or Grade 4-5 Adverse Reactions ≥2%'''
[[File:table2_def.png|thumb|none|400px|This image is provided by the National Library of Medicine.]]
<SMALL>DEFITELIO: Defibrotide's Brand name</SMALL>
|drugInteractions=:*[[Antithrombotic]] Agents
 
Defibrotide may enhance the pharmacodynamic activity of [[antithrombotic]]/[[fibrinolytic]] drugs such as [[heparin]] or [[alteplase]]. Concomitant use of Defibrotide with antithrombotic or fibrinolytic drugs is contraindicated because of an increased risk of [[hemorrhage]].
|FDAPregCat=N
|useInPregnancyFDA=:*Risk Summary
 
There are no available data on Defibrotide use in pregnant women. When administered to pregnant rabbits during the period of [[organogenesis]] at doses that were comparable to the recommended human dose based on body surface area, Defibrotide sodium decreased the number of implantations and viable fetuses. Advise pregnant women of the potential risk of [[miscarriage]].
 
The estimated background risk of major birth defects and [[miscarriage]] for the indicated population is unknown. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2-4% and 15-20%, respectively.
 
:*Data
::*Animal Data
 
Embryo-Fetal [[toxicity]] assessment was attempted in rats and rabbits, but was not possible because of high maternal mortality, [[abortion]], and fetal resorption at all doses. Pregnant rats were administered Defibrotide sodium from gestational day (GD) 6 to 15 at 0, 240, 1200, and 4800 mg/kg/day by continuous [[intravenous infusion]] over 24 hours or at 60, 120, and 240 mg/kg/day by 2-hour infusions 4 times per day. Pregnant rabbits were administered Defibrotide sodium at 0, 30, 60, or 120 mg/kg/day from GD 6 to 18 by 2-hour infusions 4 times per day.
 
In another study in pregnant rabbits, 3 separate subgroups of animals were treated with doses of 80 mg/kg/day Defibrotide sodium administered by 2-hour infusions 4 times per day for 5 days each in a staggered manner during the [[organogenesis]] period. The dose of 80 mg/kg/day is approximately equivalent to the recommended clinical dose on a mg/m2 basis. Subgroup 1 was dosed from GD 6 to 10, subgroup 2 was dosed from GD 10 to 14, and subgroup 3 was dosed from GD 14 to 18. An increased incidence of unilateral implantation was observed in Defibrotide sodium-treated animals. Treatment with Defibrotide sodium resulted in a decreased number of implantations and viable fetuses.
|useInNursing=There is no information regarding the presence of Defibrotide in human milk, the effects on the breastfed infant, or the effects on milk production. Because of the potential for serious adverse reactions, including [[bleeding]] in a breastfed infant, advise patients that breastfeeding is not recommended during treatment with Defibrotide.
|useInPed=The safety and effectiveness of Defibrotide have been established in pediatric patients. Use of Defibrotide is supported by evidence from an adequate and well-controlled study and a dose finding study of Defibrotide in adult and pediatric patients with [[VOD]] with evidence of renal or pulmonary dysfunction following [[HSCT]]. The [[clinical trial]]s enrolled 66 pediatric patients in the following age groups: 22 infants (1 month up to less than 2 years), 30 children (2 years up to less than 12 years), and 14 adolescents (12 years to less than 17 years). The efficacy and safety outcomes were consistent across pediatric and adult patients in the clinical trials.
 
:*Juvenile Animal Toxicity Data
 
A juvenile toxicity study in 21-day-old rats was conducted with intravenous [[bolus]] administration of Defibrotide sodium at 40, 150, or 320 mg/kg/day for 4 weeks. A delayed mean age of [[preputial]] separation was observed at all doses, suggesting a delay in onset of male puberty. The dose of 40 mg/kg/day is approximately 0.4 times the clinical dose on a mg/m2 basis for a child. The relevance of this finding for the onset of male puberty in humans is unknown.
|useInGeri=Clinical studies of Defibrotide did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.
|administration=:*'''Administration Instructions'''
::*Defibrotide must be diluted prior to infusion.
::*Prior to administration of Defibrotide, confirm that the patient is not experiencing clinically significant [[bleeding]] and is [[hemodynamically stable]] on no more than one [[vasopressor]].
::*Administer Defibrotide by constant [[intravenous infusion]] over a 2-hour period.
::*Administer the diluted Defibrotide solution using an infusion set equipped with a 0.2 micron in-line filter. Flush the intravenous administration line (peripheral or central) with 5% [[Dextrose]] Injection, USP or 0.9% [[Sodium Chloride]] Injection, USP immediately before and after administration.
::*Do not co‑administer Defibrotide and other intravenous drugs concurrently within the same intravenous line.
 
:*'''Preparation Instructions'''
Dilute Defibrotide in 5% [[Dextrose]] Injection, USP or 0.9% [[Sodium Chloride]] Injection, USP to a concentration of 4 mg/mL to 20 mg/mL. Administer the diluted solution over 2 hours.
 
Vials contain no antimicrobial preservatives and are intended for a single-patient-use only. Partially used vials should be discarded. Use the diluted Defibrotide solution within 4 hours if stored at room temperature or within 24 hours if stored under refrigeration. Up to four doses of Defibrotide solution may be prepared at one time, if refrigerated.
 
Preparation Instructions:
 
::*Determine the dose (mg) and number of vials of Defibrotide based on the individual patient’s baseline weight (weight prior to the preparative regimen for [[HSCT]]).
::*Calculate the volume of Defibrotide needed, withdraw this amount from the vial(s) and add it to the infusion bag containing 0.9% [[Sodium Chloride]] Injection or 5% [[Dextrose]] Injection for each dose to make a final concentration of 4 mg/mL to 20 mg/mL.
::*Gently mix the solution for infusion.
::*[[Parenteral]] drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Only clear solutions without visible particles should be used. Depending on the type and amount of diluent, the color of the diluted solution may vary from colorless to light yellow.
|overdose=There are no known cases of overdose with Defibrotide. There is no known [[antidote]] for Defibrotide, and Defibrotide is not [[Dialysis|dialyzable]]. If an overdose occurs, institute general supportive measures.
 
|drugBox={{Drugbox2
| Verifiedfields = changed
| verifiedrevid = 447578248
| IUPAC_name =
<!-- Clinical data -->
| tradename =
| Drugs.com = {{drugs.com|international|defibrotide}}
| pregnancy_category = X
| legal_status = Rx only (where available)
| routes_of_administration = oral, i.m., i.v.
<!-- Pharmacokinetic data -->
| bioavailability = 58 - 70% orally (i.v. and i.m. = 100%)
| protein_bound =
| metabolism =
| elimination_half-life = t1/2-alpha = minutes; t1/2-beta = a few hours
<!-- Identifiers -->
| CAS_number_Ref = {{cascite|correct|??}}
| CAS_number = 83712-60-1
| ATC_prefix = B01
| ATC_suffix = AX01
| ATC_supplemental =  
| ATC_supplemental =  
| PubChem =  
| PubChem =  
| DrugBank =  
| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| chemical_formula =  
| ChemSpiderID = none
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB04932
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 438HCF2X0M
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D07423
<!-- Chemical data -->
| chemical_formula =
| molecular_weight =  
| molecular_weight =  
| bioavailability = 58 - 70% orally (i.v. and i.m. = 100%)
| protein_bound =
| metabolism =
| elimination_half-life = t1/2-alpha = minutes; t1/2-beta = a few hours
| pregnancy_category = X
| legal_status = Rx only (where available)
| routes_of_administration = oral, i.m., i.v.
}}
}}
{{SI}}


{{CMG}}
|mechAction=The mechanism of action of Defibrotide sodium has not been fully elucidated. [[In vitro]], Defibrotide sodium enhances the [[enzymatic activity]] of [[plasmin]] to [[hydrolyze]] [[fibrin clots]]. Studies evaluating the pharmacological effects of Defibrotide sodium on [[endothelial cells]] (ECs) were conducted primarily in the human [[microvascular]] [[endothelial cell]] line. In vitro, Defibrotide sodium increased tissue [[plasminogen activator]] ([[t-PA]]) and [[thrombomodulin]] expression, and decreased [[von Willebrand factor]] ([[vWF]]) and [[plasminogen activator inhibitor‑1]] ([[PAI-1]]) expression, thereby reducing EC activation and increasing EC‑mediated [[fibrinolysis]]. Defibrotide sodium protected ECs from damage caused by [[chemotherapy]], [[tumor necrosis factor-α]] ([[TNF-α]]), serum starvation, and perfusion.
|structure=Defibrotide sodium is an [[oligonucleotide]] mixture with [[profibrinolytic]] properties. The chemical name of Defibrotide sodium is polydeoxyribonucleotide, sodium salt. Defibrotide sodium is a polydisperse mixture of predominantly single-stranded (ss) polydeoxyribonucleotide sodium salts derived from porcine intestinal tissue having a mean weighted molecular weight of 13-20 kDa, and a potency of 27-39 and 28-38 biological units per mg as determined by two separate assays measuring the release of a product formed by contact between Defibrotide sodium, [[plasmin]] and a plasmin substrate. The primary structure of Defibrotide sodium is shown below.
 
[[File:def11.png|thumb|none|400px|This image is provided by the National Library of Medicine.]]
 
 
Defibrotide sodium injection is a clear, light yellow to brown, sterile, preservative-free solution in a single-patient-use vial for intravenous use. Each milliliter of the injection contains 80 mg of Defibrotide sodium and 10 mg of [[Sodium Citrate]], USP, in Water for Injection, USP. [[Hydrochloric Acid]], NF, and/or [[Sodium Hydroxide]], NF, may have been used to adjust [[pH]] to 6.8-7.8.
|PD=:*[[Cardiac Electrophysiology]]
 
At a dose 2.4 times the maximum recommended dose, Defibrotide does not prolong the [[QTc interval]] to any clinically relevant extent.
 
:*[[PAI-1]] Inhibition
 
[[Plasma concentration]]s of PAI-1 were assessed on an exploratory basis as a potential [[pharmacodynamic]] marker for efficacy in Study 2. PAI-1 is an inhibitor of [[t-PA]] and therefore of [[fibrinolysis]]. Mean PAI-1 levels on Days 7 and 14 were lower than those at baseline in patients with complete response (CR) and in those who were alive at Day+100, but this trend did not reach statistical significance. There were no statistically significant differences in mean PAI-1 levels by treatment or outcome.
|PK=:*'''[[Absorption]]'''
 
After intravenous administration, [[peak plasma concentration]]s of Defibrotide sodium occur approximately at the end of each infusion.
 
:*'''[[Distribution]]'''
 
Defibrotide sodium is highly bound to human plasma proteins (average 93%) and has a volume of distribution of 8.1 to 9.1 L.
 
:*'''[[Elimination]]'''


Metabolism followed by urinary excretion is likely the main route of elimination. The estimated total clearance was 3.4 to 6.1 L/h. The elimination [[half-life]] of Defibrotide sodium is less than 2 hours. Similar plasma concentration profiles were observed in [[VOD]] patients after initial and multiple-dose administration of 6.25 mg/kg every 6 hours for 5 days. Therefore, no accumulation is expected following multiple-dose administration.


::*[[Metabolism]]


==Overview==
Though the precise pathway of Defibrotide sodium degradation in plasma [[in vivo]] is largely unknown, it has been suggested that [[nucleases]], [[nucleotidases]], [[nucleosidases]], [[deaminases]], and [[phosphorylases]] metabolize [[polynucleotides]] progressively to [[oligonucleotides]], [[nucleotides]], [[nucleosides]], and then to the free 2'-deoxyribose sugar, [[purine]] and [[pyrimidine]] bases.
'''Defibrotide''' is a [[deoxyribonucleic acid]] derivative (single stranded) derived from cow [[lung]] or porcine [[mucosa]]. It is an [[anticoagulant]] with a multiple mode of action (see below).


==Pharmacokinetics==
The [[biotransformation]] of Defibrotide sodium was investigated [[in vitro]] by incubation with human hepatocytes from donors of different ages and showed that Defibrotide sodium does not undergo appreciable metabolism by human [[hepatocyte]] cells.
Defibrotide is available as an oral, [[intravenous]], and [[intramuscular]] formulation. Its oral [[bioavailability]] is in the range of 58-70% of the [[Route of administration#Parenteral by injection or infusion|parenteral]] forms. T1/2 alpha is in the range of minutes while T1/2 beta is in the range of hours in studies with oral [[Isotopic labeling|radiolabelled]] defibrotide. These data suggest that defibrotide, in spite of its macromolecular nature, is absorbed well after oral administration. Due to the drug's short [[half-life]], it is necessary to give the daily dose divided in 2 to 4 doses (see below).


==Mode of action==
::*[[Excretion]]
The drug appears to prevent the formation of [[blood clots]] and to help dissolve blood clots by increasing levels of [[prostaglandin]] I2, E2, and [[prostacyclin]], altering platelet activity, increasing tissue plasminogen activator ([[tPA]]-)function, and decreasing activity of tissue plasminogen activator inhibitor. Prostaglandin I2 relaxes the smooth muscle of blood vessels and prevents platelets from adhering to each other. Prostaglandin E2 at certain concentrations also inhibits [[platelet aggregation]]. Moreover, the drug provides additional beneficial anti-inflammatory and antiischemic activities as recent sudies have shown. It is yet unclear, if the latter effects can be utilized clinically (e.g., treatment of ischemic stroke).


Unlike heparin and warfarin, defibrotide appears to have a relatively mild anticoagulant activity, which may be beneficial in the treatment of patients at high risk of bleeding complications. Nevertheless, patients with known bleeding disorders (e.g. hemophilia A) or recent abnormal bleedings should be treated cautiously and under close medical supervision.
After administration of 6.25 mg/kg to 15 mg/kg doses of Defibrotide as 2-hour infusions, approximately 5-15% of the total dose was excreted in urine as Defibrotide sodium, with the majority excreted during the first 4 hours.


The drug is marketed under the brand names Dasovas (FM), Noravid, and Prociclide in a variety of countries, but is currently not approved in the USA. The manufacturer is Gentium.
:*'''Specific Populations'''


==Usual indications==
::*Age: Pediatric Population
Defibrotide is used to treat or prevent a failure of normal blood flow ([[Veno-occlusive disease|occlusive venous disease]], OVD) in the liver of patients who have had bone marrow transplants or received certain drugs such as oral [[estrogen]]s, [[mercaptopurine]], and many others. Without intensive treatment OVD is often a fatal condition, leading to multiorgan failure. It has repeatedly been reported that defibrotide was able to resolve the condition completely and was well tolerated.


Other indications are: peripheral obliterative arterial disease, thrombophlebitis, and Raynaud's phenomenon. In very high doses defibrotide is useful as treatment of acute myocardial infarction. The drug may also be used for the pre- and postoperative prophylaxis of deep venous thrombosis and can replace the heparin use during hemodialytic treatments.
Insufficient [[PK]] data were collected in pediatric patients to draw conclusions.


==Potential indications in the future==
::*[[Renal Impairment]]
Other recent preclinical studies have demonstrated that defibrotide used in conjunction with Granulocyte Colony-Stimulating Factor (rhG-CSF) significantly increases the number of Peripheral Blood Progenitor Cells (Stem cells). The benefit of this increase in stem cells may be crucial for a variety of clinical indications, including graft engineering procedures and gene therapy programs. This would expand the clinical usefulness of defibrotide to a complete distinct area.


Very recently (since early 2006) combination therapy trials (phase I/II) with defibrotide plus [[melphalan]], [[prednisone]], and [[thalidomide]] in patients with [[multiple myeloma]] have been conducted. The addition of defibrotide is expected to decrease the myelosuppresive toxicity of melphalan. However, is too early for any definitive results at that stage.
The safety, tolerability, and [[pharmacokinetics]] of 6.25 mg/kg as 2-hour [[intravenous infusion]]s of Defibrotide were evaluated in patients with [[Hemodialysis]]-dependent [[End Stage Renal Disease]] ([[ESRD]]) during hemodialysis and on days off [[dialysis]], and in patients with severe renal disease or ESRD not requiring dialysis. Defibrotide sodium was not removed by hemodialysis, which had no notable effect on plasma [[clearance]] of Defibrotide sodium. Terminal half-lives were consistently less than 2 hours, and there was no accumulation of Defibrotide sodium following repeated dosing. Defibrotide sodium exposure ([[AUC]]) in patients with severe [[renal impairment]] or ESRD was 50% to 60% higher than that observed in matched healthy subjects. [[Peak concentration]] ([[Cmax]]) was 35% to 37% higher following single- and multiple-dose administration of Defibrotide sodium.


==Cautions and contraindications==
:*'''Drug Interactions'''
* The efficacy of the drug has been reported to be poorer in patients with diabetes mellitus.
* Pregnancy : The drug should not be used during pregnancy, because adequate and well controlled human studies do not exist.
* Lactation : No human data is available. In order to avoid damage to the newborn, the nursing mother should either discontinue the drug or breastfeeding, taking into account the importance of treatment to the mother.
* Known Bleeding Disorders or Bleeding Tendencies having occurred recently : Defibrotide should be used cautiously. Before initiation of treatment, the usual coagulation values should be obtained as baseline and regularly controlled under treatment. The patient should be observed regularly regarding local or systemic bleeding events.


==Side effects==
[[Pharmacokinetic]] drug-drug interactions are unlikely at therapeutic dose. Data from [[in vitro]] studies using human biomaterial demonstrate that Defibrotide sodium does not induce (CYP1A2, CYP2B6, CYP3A4, UGT1A1) or inhibit (CYP1A2, CYP2B6, CYP3A4, CYP2C8, CYP2C9, CYP2C19, CYP2D6, UGT1A1, UGT2B7) the major drug metabolizing [[enzymes]] and is not a substrate or inhibitor of the major drug uptake transporters (OAT1, OAT3, OCT1, OCT2, OATP1B1, OATP1B3) or efflux transporters ([[P-gp]] and BCRP).
Increased bleeding and bruising tendency, irritation at the injection site, nausea, vomiting, heartburn, low blood pressure. Serious allergic reactions have not been observed so far.  


==Drug interactions==  
There is some evidence (animal studies, ex vivo human plasma, and healthy volunteers) that Defibrotide sodium may enhance the [[pharmacodynamic]] activity of [[heparin]] and [[alteplase]].
Use of [[heparin]] with defibrotide may increase the aPTT, reflecting reduced ability of the body to form a clot. Nothing is known about the concomitant application of other anticoagulants than heparin and dextran containing plasma-expanders, but it can be anticipated that the risk of serious bleeding will be increased considerably.  
|nonClinToxic=======[[Carcinogenesis]], [[Mutagenesis]], Impairment of [[Fertility]]======
No carcinogenicity studies have been conducted with intravenous administration of Defibrotide sodium.


==Usual doses==
Defibrotide sodium was not mutagenic [[in vitro]] in a bacterial reverse mutation assay (Ames assay). Defibrotide sodium was not [[clastogenic]] in an [[in vitro]] chromosomal aberrations assay in Chinese hamster ovary cells or an in vivo micronucleus assay conducted in bone marrow from rats administered Defibrotide sodium by intravenous infusion.
Doses of up to 5.6 grams per day have been used for the treatment of acute myocardial infarction. A daily dose of 800 mg intravenously or intramuscularly for 7-8 days starting 1 day preoperatively is usual given for the prevention of deep venous thrombosis. Doses of 400 to 1200 mg/day have been used for the treatment of peripheral obliterative arterial disease, thrombophlebitis, and Raynaud's phenomenon. The daily dose is divided into 2-4 doses.  


A bolus of 100 mg to 400 mg intravenously given every hour or a continuous intravenous infusion to a total dose of 800 mg has been used during renal hemodialysis.  
Studies of fertility were not conducted with Defibrotide sodium administered by the intravenous route. In repeat dose general [[toxicology]] studies, when Defibrotide sodium was administered intravenously to rats and dogs for up to 13 weeks, there were no effects on male or female reproductive organs.


==External references==
======Animal [[Toxicology]] and/or [[Pharmacology]]======
* Palmer KJ, Goa KL. Defibrotide: a review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in vascular disorders. Drugs 1993;45:259-94.
In the 13-week toxicity studies in rats and dogs, intravenous administration of Defibrotide sodium transiently prolonged [[activated partial thromboplastin time]] ([[APTT]]) at 1200 and 4800 mg/kg/day administered as a continuous infusion in rats and at 300 and 1600 mg/kg/day administered in 2-hour infusions 4 times daily in dogs. [[Prothrombin time]] (PT) was also transiently increased at 4800 mg/kg/day in rats. These findings were observed at doses at least 6 times higher on a mg/m2 basis than the clinical dose of 25 mg/kg/day. The effects on APTT and PT may be due to direct effects on [[coagulation]] based on the dose-dependent response observed.
* http://www.globalrx.com/medinfo/Defibrotide.htm
|clinicalStudies=The efficacy of Defibrotide was investigated in three studies: two prospective clinical trials (Study 1 and Study 2), and an expanded access study (Study 3).
* http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8747520&dopt=Abstract (Pharmacokinetic Aspects)
* http://www.gentium.it/Defibrotide.aspx (information provided by manufacturer)
* http://rx.onconews.org/news/Melphalan.html (on cytostatic combination therapy)
* http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16252186&query_hl=3&itool=pubmed_docsum (Report from University of Istanbul regarding healing of VOC)


{{Antithrombotics}}
Study 1 enrolled 102 adult and pediatric patients in the Defibrotide treatment group with a diagnosis of [[VOD]] according to the following criteria ([[bilirubin]] of at least 2 mg/dL and at least two of the following findings: [[hepatomegaly]], [[ascites]], and weight gain greater than 5% by Day+21 post-[[HSCT]]) with an associated diagnosis of [[multi-organ dysfunction]] (pulmonary, renal, or both) by Day+28 post-HSCT. Defibrotide was administered to the treatment group at a dose of 6.25 mg/kg infused every 6 hours for a minimum of 21 days and continued until patient was discharged from the hospital. Patients enrolled in the Defibrotide treatment group were not permitted to receive concomitant medications such as [[heparin]], [[warfarin]], or [[alteplase]] because of an increased risk of bleeding.


Study 2 included adult and pediatric patients with a diagnosis of hepatic [[VOD]] and multi-organ dysfunction following [[HSCT]], with 75 patients treated with Defibrotide at a dose of 6.25 mg/kg infused every 6 hours. The planned minimum duration of treatment was 14 days. The treatment could be continued until signs of hepatic VOD resolved.


[[Category:Anticoagulants]]
Study 3 is an expanded access program for Defibrotide for the treatment of adult and pediatric patients with hepatic [[VOD]]. The efficacy of Defibrotide was evaluated in 351 patients who had received a [[HSCT]] and developed hepatic VOD with renal or pulmonary dysfunction. All patients received Defibrotide at a dose of 6.25 mg/kg infused every 6 hours.
[[Category:Drugs]]
 
{{WikiDoc Help Menu}}
Baseline demographic information and details for patients treated in these studies are provided below in Table 3.
{{WikiDoc Sources}}
 
 
:*'''Table 3: Baseline Demographics of Patients Treated with Defibrotide at 6.25 mg/kg Every 6 Hours'''
[[File:table33_def.png|thumb|none|400px|This image is provided by the National Library of Medicine.]]
 
The efficacy of Defibrotide was based on survival at Day + 100 after [[HSCT]]. In Study 1, the survival rate was 38% (95% CI: 29%, 48%) at 100 days after [[transplantation]]. In Study 2 the survival rate was 44% (95% CI: 33%, 55%) at 100 days after transplantation. In Study 3, the Day + 100 survival was 45% (95% CI: 40%, 51%).
 
Based on published reports and analyses of patient level data for individuals with hepatic [[VOD]] with renal or pulmonary dysfunction who received [[supportive care]] or interventions other than Defibrotide, the expected Day +100 survival rates are 21% to 31%.
|howSupplied=Defibrotide sodium injection is supplied in a single-patient-use, clear glass vial as a clear, light yellow to brown, sterile, preservative-free solution for intravenous infusion. Each vial (NDC 68727-800-01) contains 200 mg/2.5 mL (at a concentration of 80 mg/mL) of Defibrotide sodium.
 
Each carton of Defibrotide sodium injection (NDC 68727-800-02) contains 10 vials.
|storage=Store Defibrotide sodium injection at 20°C-25°C (68°F-77°F); excursions permitted between 15°C to 30°C (59°F to 86°F).
|packLabel=[[File:def22.png|thumb|none|400px|This image is provided by the National Library of Medicine.]]
|fdaPatientInfo=:*[[Hemorrhage]]: Advise patients and caregivers that Defibrotide may increase the risk of [[bleeding]] (hemorrhage). Instruct patients to immediately report any signs or symptoms suggestive of hemorrhage (unusual bleeding, easy [[bruising]], blood in urine or stool, [[headache]], [[confusion]], [[slurred speech]], or altered vision).
 
:*[[Hypersensitivity]] Reactions: Ask patients if they have been treated with Defibrotide sodium previously. Instruct patients on the risk of allergic reactions, including [[anaphylaxis]]. Describe the symptoms of allergic reactions, including anaphylaxis, and instruct the patient to seek medical attention immediately if they experience such symptoms.
|brandNames=DEFITELIO®
}}

Latest revision as of 14:00, 30 January 2017

Defibrotide
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: Martin Nino [2]

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Overview

Defibrotide is an oligonucleotide mixture with profibrinolytic properties that is FDA approved for the treatment of adult and pediatric patients with hepatic veno-occlusive disease (VOD), with renal or pulmonary dysfunction following hematopoietic stem-cell transplantation (HSCT). Common adverse reactions include hypotension, diarrhea, vomiting, nausea, and epistaxis (≥10%).

Adult Indications and Dosage

FDA-Labeled Indications and Dosage (Adult)

Indications

Defibrotide is indicated for the treatment of adult and pediatric patients with hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), with renal or pulmonary dysfunction following hematopoietic stem-cell transplantation (HSCT).

Dosage

The recommended dosage of Defibrotide for adult and pediatric patients is 6.25 mg/kg every 6 hours given as a 2‑hour intravenous infusion. The dose should be based on patient’s baseline body weight, defined as the patient’s weight prior to the preparative regimen for HSCT.

Administer Defibrotide for a minimum of 21 days. If after 21 days signs and symptoms of hepatic VOD have not resolved, continue Defibrotide until resolution of VOD or up to a maximum of 60 days.

  • Treatment Modification

Treatment modification, including temporary or permanent discontinuation of Defibrotide, should follow the recommendations in Table 1.

  • Table 1: Treatment Modifications for Toxicity or Invasive Procedures
This image is provided by the National Library of Medicine.

DEFITELIO: Defibrotide's Brand name

Off-Label Use and Dosage (Adult)

Pediatric Indications and Dosage

FDA-Labeled Indications and Dosage (Pediatric)

Indications

Defibrotide is indicated for the treatment of adult and pediatric patients with hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), with renal or pulmonary dysfunction following hematopoietic stem-cell transplantation (HSCT).

Dosage

The recommended dosage of Defibrotide for adult and pediatric patients is 6.25 mg/kg every 6 hours given as a 2‑hour intravenous infusion. The dose should be based on patient’s baseline body weight, defined as the patient’s weight prior to the preparative regimen for HSCT.

Administer Defibrotide for a minimum of 21 days. If after 21 days signs and symptoms of hepatic VOD have not resolved, continue Defibrotide until resolution of VOD or up to a maximum of 60 days.

  • Treatment Modification

Treatment modification, including temporary or permanent discontinuation of Defibrotide, should follow the recommendations in Table 1.

Off-Label Use and Dosage (Pediatric)

Contraindications

The use of Defibrotide is contraindicated in the following conditions:

Concomitant administration with systemic anticoagulant or fibrinolytic therapy.
Known hypersensitivity to Defibrotide or to any of its excipients.

Warnings

Defibrotide increased the activity of fibrinolytic enzymes in vitro, and it may increase the risk of bleeding in patients with VOD after hematopoietic stem-cell transplantation (HSCT). Do not initiate Defibrotide in patients with active bleeding. Monitor patients for signs of bleeding. If patients on Defibrotide develop bleeding, discontinue Defibrotide, treat the underlying cause, and provide supportive care until the bleeding has stopped.

Concomitant use of Defibrotide and a systemic anticoagulant or fibrinolytic therapy (not including use for routine maintenance or reopening of central venous lines) may increase the risk of bleeding. Discontinue anticoagulants and fibrinolytic agents prior to Defibrotide treatment, and consider delaying the start of Defibrotide administration until the effects of the anticoagulant have abated.

Hypersensitivity reactions have occurred in less than 2% of patients treated with Defibrotide. These reactions include rash, urticaria and angioedema. One case of an anaphylactic reaction was reported in a patient who had previously received Defibrotide. Monitor patients for hypersensitivity reactions, especially if there is a history of previous exposure. If a severe hypersensitivity reaction occurs, discontinue Defibrotide, treat according to the standard of care, and monitor until symptoms resolve.

Adverse Reactions

Clinical Trials Experience

The following adverse reactions are discussed in greater detail in other sections of the labeling:

  • Hemorrhage
  • Hypersensitivity Reactions

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 Defibrotide was determined in 176 adult and pediatric patients with hepatic VOD with pulmonary and/or renal dysfunction following HSCT who were treated with Defibrotide 6.25 mg/kg every 6 hours. Patients were excluded from these trials if at time of study entry they had significant acute bleeding, active grades B-D graft-versus-host disease, or a requirement for multiple vasopressors to provide blood pressure support. For the purposes of adverse event recording in the clinical trials, events were not required to be reported if they were related to the hepatic VOD, or if they were expected to occur after hematopoietic stem-cell transplantation (HSCT), unless they were serious or Grade 4-5.

The median age of the safety population was 25 years (range: 1 month to 72 years), and 63% were ≥17 years of age. A total of 60% of patients were male, 78% were white, 89% had undergone allogeneic HSCT, and the underlying diagnosis was acute leukemia for 43%. At study entry, 13% were dialysis dependent and 18% were ventilator dependent. Defibrotide was administered for a median of 21 days (range: 1 to 83 days).

Information about adverse reactions resulting in permanent discontinuation of Defibrotide was available for 102 patients, and 35 (34%) of these patients had an adverse reaction with permanent discontinuation. Adverse reactions leading to permanent discontinuation included pulmonary alveolar hemorrhage in 5 (5%) patients; pulmonary hemorrhage, hypotension, catheter site hemorrhage, and multi-organ failure, each in 3 (3%) patients; and cerebral hemorrhage and sepsis, each in 2 (2%) patients.

Information about adverse reactions of any grade was available for all 176 patients. The most common adverse reactions (incidence ≥10% and independent of causality) were hypotension, diarrhea, vomiting, nausea, and epistaxis. The most common serious adverse reactions (incidence ≥5% and independent of causality) were hypotension (11%) and pulmonary alveolar hemorrhage (7%). Hemorrhage events of any type and any grade were reported for 104 (59%) of the patients, and the events were grade 4-5 in 35 (20%).

Table 2 presents adverse reactions independent of causality ≥10% any grade or Grade 4/5 ≥2% reported in patients treated with Defibrotide.

  • Table 2: Adverse Reactions(a) ≥10% or Grade 4-5 Adverse Reactions ≥2%
This image is provided by the National Library of Medicine.

DEFITELIO: Defibrotide's Brand name

Postmarketing Experience

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

Drug Interactions

Defibrotide may enhance the pharmacodynamic activity of antithrombotic/fibrinolytic drugs such as heparin or alteplase. Concomitant use of Defibrotide with antithrombotic or fibrinolytic drugs is contraindicated because of an increased risk of hemorrhage.

Use in Specific Populations

Pregnancy

Pregnancy Category (FDA): N

  • Risk Summary

There are no available data on Defibrotide use in pregnant women. When administered to pregnant rabbits during the period of organogenesis at doses that were comparable to the recommended human dose based on body surface area, Defibrotide sodium decreased the number of implantations and viable fetuses. Advise pregnant women of the potential risk of miscarriage.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2-4% and 15-20%, respectively.

  • Data
  • Animal Data

Embryo-Fetal toxicity assessment was attempted in rats and rabbits, but was not possible because of high maternal mortality, abortion, and fetal resorption at all doses. Pregnant rats were administered Defibrotide sodium from gestational day (GD) 6 to 15 at 0, 240, 1200, and 4800 mg/kg/day by continuous intravenous infusion over 24 hours or at 60, 120, and 240 mg/kg/day by 2-hour infusions 4 times per day. Pregnant rabbits were administered Defibrotide sodium at 0, 30, 60, or 120 mg/kg/day from GD 6 to 18 by 2-hour infusions 4 times per day.

In another study in pregnant rabbits, 3 separate subgroups of animals were treated with doses of 80 mg/kg/day Defibrotide sodium administered by 2-hour infusions 4 times per day for 5 days each in a staggered manner during the organogenesis period. The dose of 80 mg/kg/day is approximately equivalent to the recommended clinical dose on a mg/m2 basis. Subgroup 1 was dosed from GD 6 to 10, subgroup 2 was dosed from GD 10 to 14, and subgroup 3 was dosed from GD 14 to 18. An increased incidence of unilateral implantation was observed in Defibrotide sodium-treated animals. Treatment with Defibrotide sodium resulted in a decreased number of implantations and viable fetuses.
Pregnancy Category (AUS): There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Defibrotide in women who are pregnant.

Labor and Delivery

There is no FDA guidance on use of Defibrotide during labor and delivery.

Nursing Mothers

There is no information regarding the presence of Defibrotide in human milk, the effects on the breastfed infant, or the effects on milk production. Because of the potential for serious adverse reactions, including bleeding in a breastfed infant, advise patients that breastfeeding is not recommended during treatment with Defibrotide.

Pediatric Use

The safety and effectiveness of Defibrotide have been established in pediatric patients. Use of Defibrotide is supported by evidence from an adequate and well-controlled study and a dose finding study of Defibrotide in adult and pediatric patients with VOD with evidence of renal or pulmonary dysfunction following HSCT. The clinical trials enrolled 66 pediatric patients in the following age groups: 22 infants (1 month up to less than 2 years), 30 children (2 years up to less than 12 years), and 14 adolescents (12 years to less than 17 years). The efficacy and safety outcomes were consistent across pediatric and adult patients in the clinical trials.

  • Juvenile Animal Toxicity Data

A juvenile toxicity study in 21-day-old rats was conducted with intravenous bolus administration of Defibrotide sodium at 40, 150, or 320 mg/kg/day for 4 weeks. A delayed mean age of preputial separation was observed at all doses, suggesting a delay in onset of male puberty. The dose of 40 mg/kg/day is approximately 0.4 times the clinical dose on a mg/m2 basis for a child. The relevance of this finding for the onset of male puberty in humans is unknown.

Geriatic Use

Clinical studies of Defibrotide did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.

Gender

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

Race

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

Renal Impairment

There is no FDA guidance on the use of Defibrotide in patients with renal impairment.

Hepatic Impairment

There is no FDA guidance on the use of Defibrotide in patients with hepatic impairment.

Females of Reproductive Potential and Males

There is no FDA guidance on the use of Defibrotide in women of reproductive potentials and males.

Immunocompromised Patients

There is no FDA guidance one the use of Defibrotide in patients who are immunocompromised.

Administration and Monitoring

Administration

  • Administration Instructions
  • Defibrotide must be diluted prior to infusion.
  • Prior to administration of Defibrotide, confirm that the patient is not experiencing clinically significant bleeding and is hemodynamically stable on no more than one vasopressor.
  • Administer Defibrotide by constant intravenous infusion over a 2-hour period.
  • Administer the diluted Defibrotide solution using an infusion set equipped with a 0.2 micron in-line filter. Flush the intravenous administration line (peripheral or central) with 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP immediately before and after administration.
  • Do not co‑administer Defibrotide and other intravenous drugs concurrently within the same intravenous line.
  • Preparation Instructions

Dilute Defibrotide in 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP to a concentration of 4 mg/mL to 20 mg/mL. Administer the diluted solution over 2 hours.

Vials contain no antimicrobial preservatives and are intended for a single-patient-use only. Partially used vials should be discarded. Use the diluted Defibrotide solution within 4 hours if stored at room temperature or within 24 hours if stored under refrigeration. Up to four doses of Defibrotide solution may be prepared at one time, if refrigerated.

Preparation Instructions:

  • Determine the dose (mg) and number of vials of Defibrotide based on the individual patient’s baseline weight (weight prior to the preparative regimen for HSCT).
  • Calculate the volume of Defibrotide needed, withdraw this amount from the vial(s) and add it to the infusion bag containing 0.9% Sodium Chloride Injection or 5% Dextrose Injection for each dose to make a final concentration of 4 mg/mL to 20 mg/mL.
  • Gently mix the solution for infusion.
  • Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Only clear solutions without visible particles should be used. Depending on the type and amount of diluent, the color of the diluted solution may vary from colorless to light yellow.

Monitoring

There is limited information regarding Defibrotide Monitoring in the drug label.

IV Compatibility

There is limited information regarding the compatibility of Defibrotide and IV administrations.

Overdosage

There are no known cases of overdose with Defibrotide. There is no known antidote for Defibrotide, and Defibrotide is not dialyzable. If an overdose occurs, institute general supportive measures.

Pharmacology

Defibrotide
Systematic (IUPAC) name
?
Identifiers
CAS number 83712-60-1
ATC code B01AX01
PubChem ?
DrugBank DB04932
Chemical data
Formula ?
Mol. mass ?
Pharmacokinetic data
Bioavailability 58 - 70% orally (i.v. and i.m. = 100%)
Metabolism ?
Half life t1/2-alpha = minutes; t1/2-beta = a few hours
Excretion ?
Therapeutic considerations
Pregnancy cat.

X

Legal status

Rx only (where available)

Routes oral, i.m., i.v.

Mechanism of Action

The mechanism of action of Defibrotide sodium has not been fully elucidated. In vitro, Defibrotide sodium enhances the enzymatic activity of plasmin to hydrolyze fibrin clots. Studies evaluating the pharmacological effects of Defibrotide sodium on endothelial cells (ECs) were conducted primarily in the human microvascular endothelial cell line. In vitro, Defibrotide sodium increased tissue plasminogen activator (t-PA) and thrombomodulin expression, and decreased von Willebrand factor (vWF) and plasminogen activator inhibitor‑1 (PAI-1) expression, thereby reducing EC activation and increasing EC‑mediated fibrinolysis. Defibrotide sodium protected ECs from damage caused by chemotherapy, tumor necrosis factor-α (TNF-α), serum starvation, and perfusion.

Structure

Defibrotide sodium is an oligonucleotide mixture with profibrinolytic properties. The chemical name of Defibrotide sodium is polydeoxyribonucleotide, sodium salt. Defibrotide sodium is a polydisperse mixture of predominantly single-stranded (ss) polydeoxyribonucleotide sodium salts derived from porcine intestinal tissue having a mean weighted molecular weight of 13-20 kDa, and a potency of 27-39 and 28-38 biological units per mg as determined by two separate assays measuring the release of a product formed by contact between Defibrotide sodium, plasmin and a plasmin substrate. The primary structure of Defibrotide sodium is shown below.

This image is provided by the National Library of Medicine.


Defibrotide sodium injection is a clear, light yellow to brown, sterile, preservative-free solution in a single-patient-use vial for intravenous use. Each milliliter of the injection contains 80 mg of Defibrotide sodium and 10 mg of Sodium Citrate, USP, in Water for Injection, USP. Hydrochloric Acid, NF, and/or Sodium Hydroxide, NF, may have been used to adjust pH to 6.8-7.8.

Pharmacodynamics

At a dose 2.4 times the maximum recommended dose, Defibrotide does not prolong the QTc interval to any clinically relevant extent.

Plasma concentrations of PAI-1 were assessed on an exploratory basis as a potential pharmacodynamic marker for efficacy in Study 2. PAI-1 is an inhibitor of t-PA and therefore of fibrinolysis. Mean PAI-1 levels on Days 7 and 14 were lower than those at baseline in patients with complete response (CR) and in those who were alive at Day+100, but this trend did not reach statistical significance. There were no statistically significant differences in mean PAI-1 levels by treatment or outcome.

Pharmacokinetics

After intravenous administration, peak plasma concentrations of Defibrotide sodium occur approximately at the end of each infusion.

Defibrotide sodium is highly bound to human plasma proteins (average 93%) and has a volume of distribution of 8.1 to 9.1 L.

Metabolism followed by urinary excretion is likely the main route of elimination. The estimated total clearance was 3.4 to 6.1 L/h. The elimination half-life of Defibrotide sodium is less than 2 hours. Similar plasma concentration profiles were observed in VOD patients after initial and multiple-dose administration of 6.25 mg/kg every 6 hours for 5 days. Therefore, no accumulation is expected following multiple-dose administration.

Though the precise pathway of Defibrotide sodium degradation in plasma in vivo is largely unknown, it has been suggested that nucleases, nucleotidases, nucleosidases, deaminases, and phosphorylases metabolize polynucleotides progressively to oligonucleotides, nucleotides, nucleosides, and then to the free 2'-deoxyribose sugar, purine and pyrimidine bases.

The biotransformation of Defibrotide sodium was investigated in vitro by incubation with human hepatocytes from donors of different ages and showed that Defibrotide sodium does not undergo appreciable metabolism by human hepatocyte cells.

After administration of 6.25 mg/kg to 15 mg/kg doses of Defibrotide as 2-hour infusions, approximately 5-15% of the total dose was excreted in urine as Defibrotide sodium, with the majority excreted during the first 4 hours.

  • Specific Populations
  • Age: Pediatric Population

Insufficient PK data were collected in pediatric patients to draw conclusions.

The safety, tolerability, and pharmacokinetics of 6.25 mg/kg as 2-hour intravenous infusions of Defibrotide were evaluated in patients with Hemodialysis-dependent End Stage Renal Disease (ESRD) during hemodialysis and on days off dialysis, and in patients with severe renal disease or ESRD not requiring dialysis. Defibrotide sodium was not removed by hemodialysis, which had no notable effect on plasma clearance of Defibrotide sodium. Terminal half-lives were consistently less than 2 hours, and there was no accumulation of Defibrotide sodium following repeated dosing. Defibrotide sodium exposure (AUC) in patients with severe renal impairment or ESRD was 50% to 60% higher than that observed in matched healthy subjects. Peak concentration (Cmax) was 35% to 37% higher following single- and multiple-dose administration of Defibrotide sodium.

  • Drug Interactions

Pharmacokinetic drug-drug interactions are unlikely at therapeutic dose. Data from in vitro studies using human biomaterial demonstrate that Defibrotide sodium does not induce (CYP1A2, CYP2B6, CYP3A4, UGT1A1) or inhibit (CYP1A2, CYP2B6, CYP3A4, CYP2C8, CYP2C9, CYP2C19, CYP2D6, UGT1A1, UGT2B7) the major drug metabolizing enzymes and is not a substrate or inhibitor of the major drug uptake transporters (OAT1, OAT3, OCT1, OCT2, OATP1B1, OATP1B3) or efflux transporters (P-gp and BCRP).

There is some evidence (animal studies, ex vivo human plasma, and healthy volunteers) that Defibrotide sodium may enhance the pharmacodynamic activity of heparin and alteplase.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment of Fertility

No carcinogenicity studies have been conducted with intravenous administration of Defibrotide sodium.

Defibrotide sodium was not mutagenic in vitro in a bacterial reverse mutation assay (Ames assay). Defibrotide sodium was not clastogenic in an in vitro chromosomal aberrations assay in Chinese hamster ovary cells or an in vivo micronucleus assay conducted in bone marrow from rats administered Defibrotide sodium by intravenous infusion.

Studies of fertility were not conducted with Defibrotide sodium administered by the intravenous route. In repeat dose general toxicology studies, when Defibrotide sodium was administered intravenously to rats and dogs for up to 13 weeks, there were no effects on male or female reproductive organs.

Animal Toxicology and/or Pharmacology

In the 13-week toxicity studies in rats and dogs, intravenous administration of Defibrotide sodium transiently prolonged activated partial thromboplastin time (APTT) at 1200 and 4800 mg/kg/day administered as a continuous infusion in rats and at 300 and 1600 mg/kg/day administered in 2-hour infusions 4 times daily in dogs. Prothrombin time (PT) was also transiently increased at 4800 mg/kg/day in rats. These findings were observed at doses at least 6 times higher on a mg/m2 basis than the clinical dose of 25 mg/kg/day. The effects on APTT and PT may be due to direct effects on coagulation based on the dose-dependent response observed.

Clinical Studies

The efficacy of Defibrotide was investigated in three studies: two prospective clinical trials (Study 1 and Study 2), and an expanded access study (Study 3).

Study 1 enrolled 102 adult and pediatric patients in the Defibrotide treatment group with a diagnosis of VOD according to the following criteria (bilirubin of at least 2 mg/dL and at least two of the following findings: hepatomegaly, ascites, and weight gain greater than 5% by Day+21 post-HSCT) with an associated diagnosis of multi-organ dysfunction (pulmonary, renal, or both) by Day+28 post-HSCT. Defibrotide was administered to the treatment group at a dose of 6.25 mg/kg infused every 6 hours for a minimum of 21 days and continued until patient was discharged from the hospital. Patients enrolled in the Defibrotide treatment group were not permitted to receive concomitant medications such as heparin, warfarin, or alteplase because of an increased risk of bleeding.

Study 2 included adult and pediatric patients with a diagnosis of hepatic VOD and multi-organ dysfunction following HSCT, with 75 patients treated with Defibrotide at a dose of 6.25 mg/kg infused every 6 hours. The planned minimum duration of treatment was 14 days. The treatment could be continued until signs of hepatic VOD resolved.

Study 3 is an expanded access program for Defibrotide for the treatment of adult and pediatric patients with hepatic VOD. The efficacy of Defibrotide was evaluated in 351 patients who had received a HSCT and developed hepatic VOD with renal or pulmonary dysfunction. All patients received Defibrotide at a dose of 6.25 mg/kg infused every 6 hours.

Baseline demographic information and details for patients treated in these studies are provided below in Table 3.


  • Table 3: Baseline Demographics of Patients Treated with Defibrotide at 6.25 mg/kg Every 6 Hours
This image is provided by the National Library of Medicine.

The efficacy of Defibrotide was based on survival at Day + 100 after HSCT. In Study 1, the survival rate was 38% (95% CI: 29%, 48%) at 100 days after transplantation. In Study 2 the survival rate was 44% (95% CI: 33%, 55%) at 100 days after transplantation. In Study 3, the Day + 100 survival was 45% (95% CI: 40%, 51%).

Based on published reports and analyses of patient level data for individuals with hepatic VOD with renal or pulmonary dysfunction who received supportive care or interventions other than Defibrotide, the expected Day +100 survival rates are 21% to 31%.

How Supplied

Defibrotide sodium injection is supplied in a single-patient-use, clear glass vial as a clear, light yellow to brown, sterile, preservative-free solution for intravenous infusion. Each vial (NDC 68727-800-01) contains 200 mg/2.5 mL (at a concentration of 80 mg/mL) of Defibrotide sodium.

Each carton of Defibrotide sodium injection (NDC 68727-800-02) contains 10 vials.

Storage

Store Defibrotide sodium injection at 20°C-25°C (68°F-77°F); excursions permitted between 15°C to 30°C (59°F to 86°F).

Images

Drug Images

{{#ask: Page Name::Defibrotide |?Pill Name |?Drug Name |?Pill Ingred |?Pill Imprint |?Pill Dosage |?Pill Color |?Pill Shape |?Pill Size (mm) |?Pill Scoring |?NDC |?Drug Author |format=template |template=DrugPageImages |mainlabel=- |sort=Pill Name }}

Package and Label Display Panel

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{{#ask: Label Page::Defibrotide |?Label Name |format=template |template=DrugLabelImages |mainlabel=- |sort=Label Page }}

Patient Counseling Information

  • Hemorrhage: Advise patients and caregivers that Defibrotide may increase the risk of bleeding (hemorrhage). Instruct patients to immediately report any signs or symptoms suggestive of hemorrhage (unusual bleeding, easy bruising, blood in urine or stool, headache, confusion, slurred speech, or altered vision).
  • Hypersensitivity Reactions: Ask patients if they have been treated with Defibrotide sodium previously. Instruct patients on the risk of allergic reactions, including anaphylaxis. Describe the symptoms of allergic reactions, including anaphylaxis, and instruct the patient to seek medical attention immediately if they experience such symptoms.

Precautions with Alcohol

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

Brand Names

DEFITELIO®

Look-Alike Drug Names

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

Drug Shortage Status

Price

References

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