4.1. Therapeutic indications

Defitelio is indicated for the treatment of severe hepatic veno-occlusive disease (VOD) also known as sinusoidal obstruction syndrome (SOS) in haematopoietic stem-cell transplantation (HSCT) therapy.

It is indicated in adults and in adolescents, children and infants over 1 month of age.

4.2. Posology and method of administration

Defitelio must be prescribed and administered to patients by specialised physicians experienced in the diagnosis and treatment of complications of HSCT.

Posology

The recommended dose is 6.25 mg/kg body weight every 6 hours (25 mg/kg/day).

There is limited efficacy and safety data on doses above this level and consequently it is not recommended to increase the dose above 25 mg/kg/day.

The treatment should be administered for a minimum of 21 days and continued until the symptoms and signs of severe VOD resolve.

Renal impairment

Dose adjustment is not required for patients with renal impairment or who are on intermittent haemodialysis (see section 5.2).

Hepatic impairment

No formal pharmacokinetic studies have been performed in patients with hepatic impairment; however, the medicinal product has been used in clinical trials of patients developing hepatic impairment without dose adjustment with no safety issues identified. No dose adjustment is therefore recommended but careful monitoring of patients should be undertaken (see section 5.2).

Paediatric population

The recommended dose for children aged 1 month to 18 years is the same mg/kg dose as for adults i.e. 6.25 mg/kg body weight every 6 hours.

The safety and efficacy of defibrotide in children aged less than 1 month has not yet been established. No data are available. The use of Defitelio in children aged less than one month is not recommended.

Method of administration

Defitelio is for intravenous use. It is administered by intravenous infusion, over two hours.

Defitelio should always be diluted prior to use. It can be diluted with 5% glucose solution for infusion or sodium chloride 9 mg/mL (0.9%) solution for infusion, to a suitable concentration to permit infusion over 2 hours. The total volume of infusion should be determined based on the individual's patient weight. The final concentration of Defitelio should be in the range of 4 mg/mL to 20 mg/mL.

Vials are intended for a single use and unused solution from a single dose must be discarded (see section 6.6)

For instructions on dilution of the medicinal product before administration, see section 6.6.

4.3. Contraindications

- Hypersensitivity to the active substance or to any of the excipients listed in section 6.1

- Concomitant use of thrombolytic therapy (e.g. t-PA) (see section 4.5).

4.4. Special warnings and precautions for use

In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded in the patient file.

Use of medicinal products that increase the risk of haemorrhage within 24 hours of Defitelio administration (within 12 hours in the case of unfractionated heparin) is not recommended.

Concomitant systemic anticoagulant therapy (e.g. heparin, warfarin, direct thrombin inhibitors and direct factor Xa inhibitors) (see section 4.5), except for routine maintenance or reopening of central venous line, requires careful monitoring. Consideration should be given to discontinuation of Defitelio during use of such therapy.

Medicinal products that affect platelet aggregation (e.g. non–steroidal anti-inflammatory agents) should be administered with care, under close medical supervision, during Defitelio administration.

In patients who have or develop clinically significant acute bleeding requiring blood transfusion, Defitelio is not recommended or should be discontinued. Temporary discontinuation of Defitelio is recommended in patients who undergo surgery or invasive procedures at significant risk of major bleeding.

Administration of defibrotide to patients who have haemodynamic instability, defined as inability to maintain mean arterial pressure with single pressor support, is not recommended.

A bolus administration of Defitelio may cause flushing or a sensation of “generalised heat”.

This medicinal product contains 20.4 mg sodium per vial, equivalent to 1.02% of the WHO recommended maximum daily intake of 2 g sodium for an adult.

4.5. Interaction with other medicinal products and other forms of interaction

Potential interactions with recombinant t-PA

In a mouse model of thromboembolism, recombinant t-PA potentiated the antithrombotic effect of defibrotide when given intravenously and thus co-administration may present an increased risk of haemorrhage and is contraindicated (see section 4.3).

Potential interactions with antithrombotic fibrinolytic agents

Defibrotide has a profibrinolytic effect (see section 5.1) and this may potentially enhance the activity of antithrombotic/fibrinolytic medicinal products.

There is currently no reported experience in patients on the concomitant treatment with Low Molecular Weight Heparins (LMWHs), warfarin or the concomitant treatment with direct thrombin inhibitors (e.g., dabigatran) or direct Factor Xa inhibitors (e.g., rivaroxaban and apixaban). Therefore, the use of defibrotide with antithrombotic/fibrinolytic medicinal products is not recommended.

However, if used, in exceptional cases, caution should be exercised by closely monitoring the coagulation parameters (see section 4.4).

Potential interactions with other medicinal products

Defibrotide does not inhibit or induce CYP450s (see section 5.2).

4.6. Fertility, pregnancy and lactation

Contraception in males and females

Effective contraception is required for patients and partners of patients during exposure to Defitelio and for one week subsequent to discontinuation.

Pregnancy

There are no studies using defibrotide in pregnant women. Embryo-foetal developmental toxicology studies in pregnant rats and rabbits of defibrotide doses close to the recommended therapeutic human dose, revealed a high rate of haemorrhagic abortion (see section 5.3).

Defitelio should not be used during pregnancy unless the clinical condition of the woman requires treatment with Defitelio.

Breast-feeding

It is not known whether defibrotide is excreted in human milk. Considering the nature of the medicinal product, a risk to the newborns/infants is not expected. Defitelio may be used during breastfeeding.

Fertility

There are no studies investigating the effects of defibrotide on human fertility.

4.7. Effects on ability to drive and use machines

Defitelio has no or negligible influence on the ability to drive and operate machines. However, patients would not be expected to drive or operate machinery due to the nature of the underlying disease.

4.8. Undesirable effects

Summary of the Safety Profile

The safety evaluation of defibrotide is based on the safety pooled data set, which included patients who received 25 mg/kg/day of defibrotide for the treatment of VOD, from 4 clinical studies: The Phase 3 pivotal treatment study (2005-01), the Treatment-IND study, the dose-finding study (99-118), and a controlled randomised prophylaxis study (2004-000592-33). In the Phase 3 pivotal treatment study, the overall incidence of adverse events was similar in the defibrotide treatment group and in the control group (historical). The tabulated list of adverse reactions incorporates the ADRs observed in the safety pooled data set [ADR = any event reported as possibly related on at least two occasions] and TEAEs observed in the final completed Treatment-IND 2006-05 study [TEAE = any AE that started or worsened in severity after the first dose of defibrotide]. For adverse reactions reported the highest frequency was used in the table below. The safety data from the pivotal study are supported and confirmed with data from the completed Treatment-IND study.

The most frequent adverse reactions observed during the treatment of hepatic VOD are haemorrhage (including but not limited to gastrointestinal haemorrhage, pulmonary haemorrhage and epistaxis) and hypotension.

In addition, although in the defibrotide studies in VOD there have been no reports of hypersensitivity, cases of hypersensitivity including anaphylaxis were reported from a previously marketed formulation of defibrotide, consequently hypersensitivity is included as an ADR.

Tabulated list of adverse reactions

Adverse reactions observed are listed below, by system organ class and frequency. Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness. Frequencies are defined as: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100), rare (≥1/10,000 to <1/1,000), very rare (<1/10,000).

Blood and lymphatic system disorders

Common

Coagulopathy

Immune system disorders

Uncommon

Hypersensitivity

Anaphylactic reaction

Nervous system disorders

Common

Cerebral haemorrhage

Uncommon

Cerebral haematoma

Eye disorders

Uncommon

Conjunctival haemorrhage

Vascular disorders

Very common

Hypotension

Common

Haemorrhage

Respiratory, thoracic and mediastinal disorders

Common

Pulmonary haemorrhage

Epistaxis

Uncommon

Haemothorax

Gastrointestinal disorders

Common

Gastrointestinal haemorrhage

Vomiting

Diarrhoea

Nausea

Haematemesis

Mouth haemorrhage

Uncommon

Melaena

Skin and subcutaneous tissue disorders

Common

Rash

Pruritus

Petechiae

Uncommon

Ecchymosis

Renal and urinary disorders

Common

Haematuria

General disorders and administration site conditions

Common

Catheter site haemorrhage

Pyrexia

Uncommon

Injection site haemorrhage

Paediatric population

In the treatment studies over 50% of the patients were children. In doses above the recommended dose of 25 mg/kg/day there was a higher proportion of patients with bleeding events in the high dose group but since many events occurred in the follow-up period, a clear relationship with defibrotide treatment could not be determined. In the paediatric prevention study at 25 mg/kg/day there was an increased incidence of any bleeding events in the defibrotide group compared with the treatment group.

However there was no difference in incidence of serious bleeding or bleeding events with fatal outcome.

The frequency nature and severity of adverse reactions in children are otherwise the same as in adults. No special precautions are indicated.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorization of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via

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4.9. Overdose

There is no specific antidote for overdose and treatment should be symptomatic. Defibrotide is not removed by dialysis (see section 5.2).