Treprostinil

Remodulin is a prostacyclin mimetic indicated for: Treatment of pulmonary arterial hypertension (PAH; WHO Group 1) to diminish symptoms associated with exercise. Studies establishing effectiveness included patients with NYHA Functional Class II-IV symptoms and etiologies of idiopathic or heritable PAH (58%), PAH associated with congenital systemic-to-pulmonary shunts (23%), or PAH associated with connective tissue diseases (19%). ( 1.1 ) Patients who require transition from epoprostenol, to reduce the rate of clinical deterioration. The risks and benefits of each drug should be carefully considered prior to transition. ( 1.2 )

1.1 Pulmonary Arterial Hypertension Remodulin is indicated for the treatment of pulmonary arterial hypertension (PAH; WHO Group 1) to diminish symptoms associated with exercise. Studies establishing effectiveness included patients with NYHA Functional Class II-IV symptoms and etiologies of idiopathic or heritable PAH (58%), PAH associated with congenital systemic-to-pulmonary shunts (23%), or PAH associated with connective tissue diseases (19%) [see Clinical Studies (14.1) ] .

1.2 Pulmonary Arterial Hypertension in Patients Requiring Transition from Epoprostenol In patients with PAH requiring transition from epoprostenol, Remodulin is indicated to diminish the rate of clinical deterioration. Consider the risks and benefits of each drug prior to transition.

20-mL vial containing 2 mg treprostinil (0.1 mg per mL). 20-mL vial containing 4 mg treprostinil (0.2 mg per mL). 20-mL vial containing 8 mg treprostinil (0.4 mg per mL). 20-mL vial containing 20 mg treprostinil (1 mg per mL). 20-mL vial containing 50 mg treprostinil (2.5 mg per mL). 20-mL vial containing 100 mg treprostinil (5 mg per mL). 20-mL vial containing 200 mg treprostinil (10 mg per mL). 20-mL vial containing 400 mg treprostinil (20 mg per mL). Remodulin is supplied in 20-mL vials containing 2 mg (0.1 mg/mL), 4 mg (0.2 mg/mL), 8 mg (0.4 mg/mL), 20 mg (1 mg/mL), 50 mg (2.5 mg/mL), 100 mg (5 mg/mL), 200 mg (10 mg/mL), or 400 mg (20 mg/mL) of treprostinil. ( 3 )

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Chronic intravenous infusions delivered using an external infusion pump with an indwelling central venous catheter are associated with the risk of blood stream infections (BSIs) and sepsis, which may be fatal. ( 5.1 ) Do not abruptly lower the dose or withdraw dosing. ( 5.2 ) Remodulin may cause symptomatic hypotension. ( 5.4 ) Remodulin inhibits platelet aggregation and increases the risk of bleeding. ( 5.5 )

5.1 Risk of Catheter-Related Bloodstream Infection Chronic intravenous infusions of Remodulin delivered using an external infusion pump with an indwelling central venous catheter are associated with the risk of blood stream infections (BSIs) and sepsis, which may be fatal. Therefore, continuous subcutaneous infusion is the preferred mode of administration. In an open-label study of IV treprostinil (n=47) using an external infusion pump, there were seven catheter-related line infections during approximately 35 patient years, or about 1 BSI event per 5 years of use. A CDC survey of seven sites that used IV treprostinil for the treatment of PAH found approximately 1 BSI (defined as any positive blood culture) event per 3 years of use. Administration of IV Remodulin with a high pH glycine diluent has been associated with a lower incidence of BSIs when compared to neutral diluents (sterile water, 0.9% sodium chloride) when used along with catheter care guidelines. In an open-label study of an implantable pump (n=60), there were two blood stream infections (BSIs) related to the implant procedure during approximately 265 patient years.

5.2 Worsening PAH upon Abrupt Withdrawal or Sudden Large Dose Reduction Avoid abrupt withdrawal or sudden large reductions in dosage of Remodulin, which may result in worsening of PAH symptoms.

5.3 Patients with Hepatic Insufficiency Titrate Remodulin slowly in patients with hepatic insufficiency, because such patients will likely be exposed to greater systemic concentrations relative to patients with normal hepatic function [see Dosage and Administration (2.5) , Use in Specific Populations (8.6) , and Clinical Pharmacology (12.3) ] .

5.4 Risk of Symptomatic Hypotension Treprostinil is a pulmonary and systemic vasodilator. In patients with low systemic arterial pressure, treatment with Remodulin may produce symptomatic hypotension.

5.5 Risk of Bleeding Remodulin inhibits platelet aggregation and increases the risk of bleeding.

The following adverse reactions are discussed elsewhere in labeling: Infections associated with intravenous administration [see Warnings and Precautions (5.1) ] . Most common adverse reactions (incidence >3%) reported in clinical studies with Remodulin: subcutaneous infusion site pain and reaction, headache, diarrhea, nausea, jaw pain, vasodilatation, edema, and hypotension. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact United Therapeutics Corp. at 1-866-458-6479 or contact FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience 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. Adverse Events with Subcutaneously Administered Remodulin Patients receiving Remodulin as a subcutaneous infusion reported a wide range of adverse events, many potentially related to the underlying disease (dyspnea, fatigue, chest pain, right ventricular heart failure, and pallor). During clinical trials with subcutaneous infusion of Remodulin, infusion site pain and reaction were the most common adverse events among those treated with Remodulin. Infusion site reaction was defined as any local adverse event other than pain or bleeding/bruising at the infusion site and included symptoms such as erythema, induration, or rash. Infusion site reactions were sometimes severe and could lead to discontinuation of treatment. Table 3: Percentages of Subjects Reporting Subcutaneous Infusion Site Adverse Events Reaction Pain Placebo Remodulin Placebo Remodulin Severe 1 38 2 39 Requiring narcotics based on prescriptions for narcotics, not actual use NA medications used to treat infusion site pain were not distinguished from those used to treat site reactions NA 1 32 Leading to discontinuation 0 3 0 7 Other adverse events included diarrhea, jaw pain, edema, vasodilatation, and nausea, and these are generally considered to be related to the pharmacologic effects of Remodulin, whether administered subcutaneously or intravenously. Adverse Reactions during Chronic Dosing Table 4 lists adverse reactions that occurred at a rate of at least 3% more frequent in patients treated with subcutaneous Remodulin than with placebo in controlled trials in PAH. Table 4: Adverse Reactions in Controlled 12-Week Studies of Subcutaneous Remodulin and at least 3% more frequent than on Placebo Adverse Reaction Remodulin (N=236) Percent of Patients Placebo (N=233) Percent of Patients Infusion Site Pain 85 27 Infusion Site Reaction 83 27 Headache 27 23 Diarrhea 25 16 Nausea 22 18 Rash 14 11 Jaw Pain 13 5 Vasodilatation 11 5 Edema 9 3 Reported adverse reactions (at least 3% more frequent on drug than on placebo) are included with the exception of those too general to be informative, and those not plausibly attributable to the use of the drug, because they were associated with the condition being treated or are very common in the treated population. While hypotension occurred in both groups, the event was experienced twice as frequently in the Remodulin group as compared to the placebo group (4% in Remodulin treatment group versus 2% in placebo-controlled group). As a potent vasodilator, hypotension is possible with the administration of Remodulin. The safety of Remodulin was also studied in a long-term, open-label extension study in which 860 patients were dosed for a mean duration of 1.6 years, with a maximum exposure of 4.6 years. Twenty-nine (29%) percent achieved a dose of at least 40 ng/kg/min (max: 290 ng/kg/min). The safety profile during this chronic dosing study was similar to that observed in the 12-week placebo-controlled study except for the following suspected adverse drug reactions (occurring in at least 3% of patients): anorexia, vomiting, infusion site infection, asthenia, and abdominal pain. Adverse Events Attributable to the Drug Delivery System In controlled studies of Remodulin administered subcutaneously, there were no reports of infection related to the drug delivery system. There were 187 infusion system complications reported in 28% of patients (23% Remodulin, 33% placebo); 173 (93%) were pump related and 14 (7%) related to the infusion set. Eight of these patients (4 Remodulin, 4 placebo) reported non-serious adverse events resulting from infusion system complications. Adverse events resulting from problems with the delivery systems were typically related to either symptoms of excess Remodulin (e.g., nausea) or return of PAH symptoms (e.g., dyspnea). These events were generally resolved by correcting the delivery system pump or infusion set problem, such as replacing the syringe or battery, reprogramming the pump, or straightening a crimped infusion line. Adverse events resulting from problems with the delivery system did not lead to clinical instability or rapid deterioration. In addition to these adverse events due to the drug delivery system during subcutaneous administration, the following adverse events may be attributable to the IV mode of infusion including arm swelling, paresthesia, hematoma, and pain [see Warnings and Precautions (5.1) ] .

6.2 Post-Marketing Experience In addition to adverse reactions reported from clinical trials, the following events have been identified during post-approval use of Remodulin. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. The following events have been chosen for inclusion because of a combination of their seriousness, frequency of reporting, and potential connection to Remodulin. These events are thrombophlebitis associated with peripheral intravenous infusion, thrombocytopenia, bone pain, pruritus, dizziness, arthralgia, myalgia/muscle spasm, and pain in extremity. In addition, generalized rashes, sometimes macular or papular in nature, and cellulitis have been infrequently reported.

Remodulin dosage adjustment may be necessary if inhibitors or inducers of CYP2C8 are added or withdrawn. ( 7.1 )

7.1 Effect of CYP2C8 Inhibitors and Inducers on Treprostinil Dose adjustment of treprostinil may be necessary when co-administered with CYP2C8 inducers or inhibitors. Human pharmacokinetic studies with an oral formulation of treprostinil (treprostinil diolamine) indicated that co-administration of the cytochrome P450 (CYP) 2C8 enzyme inhibitor gemfibrozil increases exposure (both C max and AUC) to treprostinil. Co-administration of the CYP2C8 enzyme inducer rifampin decreases exposure to treprostinil. It has not been determined if the changes in exposure of treprostinil with inhibitors or inducers of CYP2C8 observed for the oral administration of treprostinil would be similar for treprostinil administered via the parenteral route [see Clinical Pharmacology (12.3) ].

8.1 Pregnancy Risk Summary Limited case reports of treprostinil use in pregnant women are insufficient to inform a drug-associated risk of adverse developmental outcomes. However, there are risks to the mother and the fetus associated with pulmonary arterial hypertension (see Clinical Considerations ) . In animal studies, no adverse reproductive and developmental effects were seen in rats at about 123 and 48 times the human exposure based on C max and AUC, respectively. In rabbits, external fetal and soft tissue malformations and skeletal malformations were observed at about 7 and 5 times the human exposure based on C max and AUC, respectively ( see Data ). The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Disease-associated maternal and embryo-fetal risk Pulmonary arterial hypertension is associated with an increased risk of maternal and fetal mortality. Data Animal reproduction studies have been conducted with treprostinil via continuous subcutaneous administration and with treprostinil diolamine administered orally. In pregnant rats, continuous subcutaneous infusions of treprostinil during organogenesis and late gestational development, at doses as high as 900 ng treprostinil/kg/min (about 117 times the starting human subcutaneous infusion rate, on a ng/m 2 basis and about 16 times the average rate achieved in clinical trials), resulted in no evidence of harm to the fetus. In pregnant rabbits, effects of continuous subcutaneous infusions of treprostinil during organogenesis were limited to an increased incidence of fetal skeletal variations (bilateral full rib or right rudimentary rib on lumbar 1) associated with maternal toxicity (reduction in body weight and food consumption) at a dose of 150 ng treprostinil/kg/min (about 41 times the starting human subcutaneous infusion rate, on a ng/m 2 basis, and 5 times the average rate used in clinical trials). In rats, continuous subcutaneous infusion of treprostinil from implantation to the end of lactation, at doses of up to 450 ng treprostinil/kg/min, did not affect the growth and development of offspring. In studies with orally administered treprostinil diolamine, no adverse effect doses for fetal viability/growth, fetal development (teratogenicity), and postnatal development were determined in rats. In pregnant rats, no evidence of harm to the fetus was observed following oral administration of treprostinil diolamine at the highest dose tested (20 mg/kg/day), which represents about 123 and 48 times the human exposure, when based on C max and AUC of the average subcutaneous infusion rate achieved in clinical trials, respectively. In pregnant rabbits, external fetal and soft tissue malformations and fetal skeletal malformation occurred. The dose at which no adverse effects were seen (0.5 mg/kg/day) represents about 7 and 5 times the human exposure, when based on C max and AUC of the average subcutaneous infusion rate achieved in clinical trials, respectively. No treprostinil treatment-related effects on labor and delivery were seen in animal studies. Animal reproduction studies are not always predictive of human response.

8.2 Lactation Risk Summary There are no data on the presence of treprostinil in human milk, the effects on the breastfed infant, or the effects on milk production.

8.4 Pediatric Use Safety and effectiveness in pediatric patients have not been established. Clinical studies of Remodulin did not include sufficient numbers of patients aged ≤16 years to determine whether they respond differently from older patients.

8.5 Geriatric Use Clinical studies of Remodulin did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

8.6 Patients with Hepatic Insufficiency Remodulin clearance is reduced in patients with hepatic insufficiency. In patients with mild or moderate hepatic insufficiency, decrease the initial dose of Remodulin to 0.625 ng/kg/min ideal body weight, and monitor closely. Remodulin has not been studied in patients with severe hepatic insufficiency [see Dosage and Administration (2.5) , Warnings and Precautions (5.3) , and Clinical Pharmacology (12.3) ] .

8.7 Patients with Renal Impairment No dose adjustments are required in patients with renal impairment. Treprostinil is not cleared by dialysis [see Clinical Pharmacology (12.3) ] .

The major pharmacologic actions of treprostinil are direct vasodilation of pulmonary and systemic arterial vascular beds, and inhibition of platelet aggregation.