DEFITELIO Solution for injection Ref.[9989] Active ingredients: Defibrotide

5.1 Hemorrhage

DEFITELIO 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 DEFITELIO in patients with active bleeding. Monitor patients for signs of bleeding. If patients on DEFITELIO develop bleeding, discontinue DEFITELIO, treat the underlying cause, and provide supportive care until the bleeding has stopped [see Dosage and Administration (2.3)].

Concomitant use of DEFITELIO 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 DEFITELIO treatment, and consider delaying the start of DEFITELIO administration until the effects of the anticoagulant have abated [see Contraindications (4)].

5.2 Hypersensitivity Reactions

Hypersensitivity reactions have occurred in less than 2% of patients treated with DEFITELIO. These reactions include rash, urticaria and angioedema. One case of an anaphylactic reaction was reported in a patient who had previously received DEFITELIO. Monitor patients for hypersensitivity reactions, especially if there is a history of previous exposure. If a severe hypersensitivity reaction occurs, discontinue DEFITELIO, treat according to the standard of care, and monitor until symptoms resolve [see Dosage and Administration (2.3)].

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

• Hemorrhage [see Warnings and Precautions (5.1)]
• Hypersensitivity Reactions [see Warnings and Precautions (5.2)]

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 DEFITELIO was determined in 176 adult and pediatric patients with hepatic VOD with pulmonary and/or renal dysfunction following HSCT who were treated with DEFITELIO 6.25 mg/kg every 6 hours [see Clinical Studies (14)]. 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. DEFITELIO was administered for a median of 21 days (range: 1 to 83 days).

Information about adverse reactions resulting in permanent discontinuation of DEFITELIO 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 DEFITELIO.

Table 2. Adverse Reactions ^a ≥10% or Grade 4-5 Adverse Reactions ≥2%:

^aExcludes events considered to be due to the underlying disease: multi-organ failure, veno-occlusive disease, respiratory failure, renal failure, and hypoxia
^b Adverse reactions considered life-threatening or fatal
^c Cerebral hemorrhage has been included in the table due to clinical relevance

Antithrombotic Agents

DEFITELIO may enhance the pharmacodynamic activity of antithrombotic/fibrinolytic drugs such as heparin or alteplase. Concomitant use of DEFITELIO with antithrombotic or fibrinolytic drugs is contraindicated because of an increased risk of hemorrhage [see Contraindications (4)].

Risk Summary

There are no available data on DEFITELIO 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/m ² 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.

Risk Summary

There is no information regarding the presence of DEFITELIO 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 DEFITELIO.

The safety and effectiveness of DEFITELIO have been established in pediatric patients. Use of DEFITELIO is supported by evidence from an adequate and well-controlled study and a dose finding study of DEFITELIO 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 [see Adverse Reactions (6) and Clinical Studies (14)].

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.

Clinical studies of DEFITELIO 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.