Treprostinil Drug Information

General

Treprostinil injection can be administered with or without further dilution with Sterile Diluent for treprostinil injection or similar approved high-pH glycine diluent (e.g., Sterile Diluent for Flolan or Sterile Diluent for Epoprostenol), Sterile Water for Injection, or 0.9% Sodium Chloride Injection prior to administration. See Table 1 below for storage and administration time limits for the different diluents. Diluted Treprostinil has been shown to be stable at ambient temperature when stored for up to14 days using high-pH glycine diluent at concentrations as low as 0.004 mg/mL (4,000 ng/mL).

Table 1: Selection of

Initial Dose for Patients New to Prostacyclin Infusion Therapy Treprostinil injection is indicated for subcutaneous (SC) or intravenous (IV) use only as a continuous infusion. Treprostinil injection is preferably infused subcutaneously, but can be administered by a central intravenous line if the subcutaneous route is not tolerated because of severe site pain or reaction. The infusion rate is initiated at 1.25 ng/kg/min.

If this initial dose cannot be tolerated because of systemic effects, reduce the infusion rate to 0.625 ng/kg/min.

Initial Dose for Patients Transitioning to an Implantable Intravenous Infusion Pump The initial dose of treprostinil injection should be the same as the current dose the patient is receiving using the external infusion pump at the time of transition.

Dosage Adjustments

The goal of chronic dosage adjustments is to establish a dose at which PAH symptoms are improved, while minimizing excessive pharmacologic effects of treprostinil injection (headache, nausea, emesis, restlessness, anxiety and infusion site pain or reaction). The infusion rate should be increased in increments of 1.25 ng/kg/min per week for the first four weeks of treatment and then 2.5 ng/kg/min per week for the remaining duration of infusion, depending on clinical response. Dosage adjustments may be undertaken more often if tolerated.

Avoid abrupt cessation of infusion. Restarting a treprostinil injection infusion within a few hours after an interruption can be done using the same dose rate. Interruptions for longer periods may require the dose of treprostinil injection to be re-titrated.

Patients with Hepatic Insufficiency

In patients with mild or moderate hepatic insufficiency, decrease the initial dose of treprostinil injection to 0.625 ng/kg/min ideal body weight. Treprostinil injection has not been studied in patients with severe hepatic insufficiency.

Administration

Inspect parenteral drug products for particulate matter and discoloration prior to administration whenever solution and container permit. If either particulate matter or discoloration is noted, do not use. Preparation Treprostinil injection is administered by subcutaneous or intravenous infusion at a calculated rate based on a patient's dose (ng/kg/min), weight (kg) and the treprostinil injection concentration (mg/mL).

For administration of Undiluted Treprostinil Injection the rate is calculated using the following formula: For administration of Diluted Treprostinil Injection the rate and concentration is calculated using the following formulas: The volume of treprostinil injection needed to make the required diluted treprostinil concentration for the given reservoir size can then be calculated using the following formula: Step 2 Volume of Treprostinil Injection (mL) = Diluted Treprostinil Concentration (mg/mL) × Total Volume of Diluted Treprostinil olution in Reservoir (mL) Treprostinil Injection Vial Strength (mg/mL) The calculated volume of treprostinil injection is then added to the reservoir along with the sufficient volume of diluent to achieve the desired total volume in the reservoir. Subcutaneous Infusion Treprostinil injection is administered subcutaneously by continuous infusion, via a subcutaneous catheter, using an infusion pump designed for subcutaneous drug delivery. The infusion pump should: be adjustable to approximately 0.002 mL/hour, have occlusion/no delivery, low battery, programming error and motor malfunction alarms, have delivery accuracy of ±6% or better, be positive pressure-driven, and have a reservoir made of polyvinyl chloride, polypropylene or glass.

Alternatively, use an infusion pump cleared for use with treprostinil injection. To avoid potential interruptions in drug delivery, the patient must have immediate access to a backup infusion pump and subcutaneous infusion sets. Intravenous Infusion External Intravenous Infusion Pump:Treprostinil injection is administered intravenously by continuous infusion via a surgically placed indwelling central venous catheter using an external infusion pump designed for intravenous drug delivery.

If clinically necessary, a temporary peripheral intravenous cannula, preferably placed in a large vein, may be used for short term administration of treprostinil injection. Use of a peripheral intravenous infusion for more than a few hours increases the risk of thrombophlebitis. The infusion pump used to administer treprostinil injection should: have occlusion/no delivery, low battery, programming error and motor malfunction alarms, have delivery accuracy of ±6% or better, be positive pressure driven, and have a reservoir made of polyvinyl chloride, polypropylene or glass.

Infusion sets with an in-line 0.22- or 0.2- micron pore size filter should be used. Implantable Intravenous Infusion Pump: Use an implantable intravenous infusion pump approved for use with treprostinil injection, such as the Implantable System for treprostinil injection (ISR). Refer to the pump manufacturer's manual for specific instructions regarding preparation, programing, implantation, and refilling.

Patients Requiring Transition from Epoprostenol Transition from epoprostenol to treprostinil injection is accomplished by initiating the infusion of treprostinil injection and increasing it, while simultaneously reducing the dose of intravenous epoprostenol. The transition to treprostinil injection should take place in a hospital with constant observation of response (e.g., walk distance and signs and symptoms of disease progression). Initiate treprostinil injection at a recommended dose of 10% of the current epoprostenol dose, and then escalate as the epoprostenol dose is decreased (see Table 2 for recommended dose titrations).

Patients are individually titrated to a dose that allows transition from epoprostenol therapy to treprostinil injection while balancing prostacyclin-limiting adverse events. Treat increases in the patient's symptoms of PAH first with increases in the dose of treprostinil injection. Treat side effects normally associated with prostacyclin and prostacyclin analogs first by decreasing the dose of epoprostenol.

Table 2: Recommended Transition Dose Changes

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 Treprostinil Injection Patients receiving treprostinil injection 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 treprostinil injection, infusion site pain and reaction were the most common adverse events among those treated with treprostinil injection.

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 a based on prescriptions for narcotics, not actual use b medications used to treat infusion site pain were not distinguished from those used to treat site reactions Other adverse events included diarrhea, jaw pain, edema, vasodilatation and nausea, and these are generally considered to be related to the pharmacologic effects of treprostinil injection, 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 treprostinil injection than with placebo in controlled trials in PAH. Table 4: Adverse Reactions in Controlled 12-Week Studies of Subcutaneous 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 treprostinil injection group as compared to the placebo group (4% in treprostinil injection treatment group versus 2% in placebo-controlled group).

As a potent vasodilator, hypotension is possible with the administration of treprostinil injection. The safety of treprostinil injection 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 treprostinil injection administered subcutaneously, there were no reports of infection related to the drug delivery system. Eight of these patients (4 treprostinil injection, 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 treprostinil injection (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.

Post-Marketing Experience

In addition to adverse reactions reported from clinical trials, the following events have been identified during post-approval use of treprostinil injection. 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 treprostinil injection.

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.

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.

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 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.

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

Signs and symptoms of overdose with treprostinil injection during clinical trials are extensions of its dose-limiting pharmacologic effects and include flushing, headache, hypotension, nausea, vomiting, and diarrhea. Most events were self-limiting and resolved with reduction or withholding of treprostinil injection. In controlled clinical trials using an external infusion pump, seven patients received some level of overdose and in open-label follow-on treatment seven additional patients received an overdose; these occurrences resulted from accidental bolus administration of treprostinil injection, errors in pump programmed rate of administration, and prescription of an incorrect dose.

In only two cases did excess delivery of treprostinil injection produce an event of substantial hemodynamic concern (hypotension, near-syncope). One pediatric patient was accidentally administered 7.5 mg of treprostinil injection via a central venous catheter. Symptoms included flushing, headache, nausea, vomiting, hypotension and seizure-like activity with loss of consciousness lasting several minutes.

The patient subsequently recovered.