Epoprostenol Drug Information

Epoprostenol for injection is indicated for the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) to improve exercise capacity. Studies establishing effectiveness included predominantly patients with NYHA Functional Class III-IV symptoms and etiologies of idiopathic or heritable PAH or PAH associated with connective tissue diseases. Epoprostenol for injection is a prostacyclin vasodilator indicated for the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) to improve exercise capacity.

Studies establishing effectiveness included predominantly patients with NYHA Functional Class III-IV symptoms and etiologies of idiopathic or heritable PAH or PAH associated with connective tissue diseases.

• Most common adverse reactions during: - Dose Initiation and Escalation: Nausea, vomiting, headache, hypotension, flushing, chest pain, anxiety, dizziness, bradycardia, dyspnea, abdominal pain, musculoskeletal pain, and tachycardia ( 6.1 ) - Chronic Dosing: Headache, jaw pain, flushing, diarrhea, nausea and vomiting, flu-like symptoms, and anxiety/nervousness ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Mylan at 1-877-446-3679 (1-877-4-INFO-RX) or 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. During clinical trials, adverse events were classified as follows: (1) adverse events during dose initiation and escalation, (2) adverse events during chronic dosing, and (3) adverse events associated with the drug delivery system. Adverse Events during Dose Initiation and Escalation During early clinical trials, epoprostenol was increased in 2 ng/kg/min increments until the patients developed symptomatic intolerance. The most common adverse events and the adverse events that limited further increases in dose were generally related to vasodilation, the major pharmacologic effect of epoprostenol. The most common dose-limiting adverse events (occurring in > 1% of patients) were nausea, vomiting, headache, hypotension, and flushing, but also include chest pain, anxiety, dizziness, bradycardia, dyspnea, abdominal pain, musculoskeletal pain, and tachycardia. Table 8 lists the adverse events reported during dose initiation and escalation in decreasing order of frequency. Table 8: Adverse Events during Dose Initiation and Escalation Adverse Events Occurring in > 1% of Patients Epoprostenol (n=391) Flushing 58% Headache 49% Nausea/vomiting 32% Hypotension 16% Anxiety, nervousness, agitation 11% Chest pain 11% Dizziness 8% Bradycardia 5% Abdominal pain 5% Musculoskeletal pain 3% Dyspnea 2% Back pain 2% Sweating 1% Dyspepsia 1% Hypesthesia/paresthesia 1% Tachycardia 1% Adverse Events during Chronic Administration Interpretation of adverse events is complicated by the clinical features of PAH, which are similar to some of the pharmacologic effects of epoprostenol (e.g., dizziness, syncope). Adverse events which may be related to the underlying disease include dyspnea, fatigue, chest pain, edema, hypoxia, right ventricular failure, and pallor. Several adverse events, on the other hand, can clearly be attributed to epoprostenol. These include hypotension, bradycardia, tachycardia, pulmonary edema, bleeding at various sites, thrombocytopenia, headache, abdominal pain, pain (unspecified), sweating, rash, arthralgia, jaw pain, flushing, diarrhea, nausea and vomiting, flu-like symptoms, anxiety/nervousness, and agitation. In addition, chest pain, fatigue, and pallor have been reported during epoprostenol therapy, and a role for the drug in these events cannot be excluded. Adverse Events during Chronic Administration for Idiopathic or Heritable PAH In an effort to separate the adverse effects of the drug from the adverse effects of the underlying disease, Table 9 lists adverse events that occurred at a rate at least 10% greater on epoprostenol than on conventional therapy in controlled trials for idiopathic or heritable PAH. Table 9: Adverse Events Regardless of Attribution Occurring in Patients with Idiopathic or Heritable PAH with ≥10% Difference between Epoprostenol and Conventional Therapy Alone Adverse Event Epoprostenol (n = 52) Conventional Therapy (n = 54) Occurrence More Common With Epoprostenol General Chills/fever/sepsis/flu-like symptoms 25% 11% Cardiovascular Tachycardia 35% 24% Flushing 42% 2% Gastrointestinal Diarrhea 37% 6% Nausea/vomiting 67% 48% Musculoskeletal Jaw pain 54% 0% Myalgia 44% 31% Nonspecific musculoskeletal pain 35% 15% Neurological Anxiety/nervousness/tremor 21% 9% Dizziness 83% 70% Headache 83% 33% Hypesthesia, hyperesthesia, paresthesia 12% 2% Thrombocytopenia has been reported during uncontrolled clinical trials in patients receiving epoprostenol. Adverse Events during Chronic Administration for PAH/SSD In an effort to separate the adverse effects of the drug from the adverse effects of the underlying disease, Table 10 lists adverse events that occurred at a rate at least 10% greater on epoprostenol in the controlled trial. Table 10: Adverse Events Regardless of Attribution Occurring in Patients with PAH/SSD With ≥10% Difference Between Epoprostenol and Conventional Therapy Alone Adverse Event Epoprostenol (n = 56) Conventional Therapy (n = 55) Cardiovascular Flushing 23% 0% Hypotension 13% 0% Gastrointestinal Anorexia 66% 47% Nausea/vomiting 41% 16% Diarrhea 50% 5% Musculoskeletal Jaw pain 75% 0% Pain/neck pain/arthralgia 84% 65% Neurological Headache 46% 5% Skin and Appendages Skin ulcer 39% 24% Eczema/rash/urticaria 25% 4% Although the relationship to epoprostenol administration has not been established, pulmonary embolism has been reported in several patients taking epoprostenol and there have been reports of hepatic failure. Adverse Events Attributable to the Drug Delivery System Chronic infusions of epoprostenol are delivered using a small, portable infusion pump through an indwelling central venous catheter. During controlled PAH trials of up to 12 weeks’ duration, the local infection rate was about 18%, and the rate for pain was about 11%. During long-term follow-up, sepsis was reported at a rate of 0.3 infections/patient per year in patients treated with epoprostenol. This rate was higher than reported in patients using chronic indwelling central venous catheters to administer parenteral nutrition, but lower than reported in oncology patients using these catheters. Malfunctions in the delivery system resulting in an inadvertent bolus of or a reduction in epoprostenol were associated with symptoms related to excess or insufficient epoprostenol, respectively. 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 epoprostenol. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to epoprostenol. Blood and Lymphatic: Anemia, hypersplenism, pancytopenia, splenomegaly. Cardiac: High output cardiac failure (consider dose reduction) [see Dosage and Administration (2.2) , Warnings and Precautions (5.1) , and Warnings and Precautions (5.3) ]. Endocrine and Metabolic: Hyperthyroidism

• Additional reductions in blood pressure may occur when epoprostenol is administered with diuretics, antihypertensive agents, or other vasodilators. When other antiplatelet agents or anticoagulants are used concomitantly, there is the potential for epoprostenol to increase the risk of bleeding. However, patients receiving infusions of epoprostenol in clinical trials were maintained on anticoagulants without evidence of increased bleeding. In clinical trials, epoprostenol was used with digoxin, diuretics, anticoagulants, oral vasodilators, and supplemental oxygen. In a pharmacokinetic substudy in patients with congestive heart failure receiving furosemide or digoxin in whom therapy with epoprostenol was initiated, apparent oral clearance values for furosemide (n = 23) and digoxin (n = 30) were decreased by 13% and 15%, respectively, on the second day of therapy and had returned to baseline values by day 87. The change in furosemide clearance value is not likely to be clinically significant. However, patients on digoxin may show elevations of digoxin concentrations after initiation of therapy with epoprostenol, which may be clinically significant in patients prone to digoxin toxicity.
• Diuretics, antihypertensive agents, or other vasodilators: reduction in blood pressure ( 7 )
• Antiplatelet agents or anticoagulants: increase the risk of bleeding ( 7 )
• Patients on digoxin: elevations of digoxin concentrations clinically significant in patients prone to digoxin toxicity ( 7 )

Pregnancy Risk Summary Limited published data from case series and case reports with epoprostenol have not established a drug associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes when used during pregnancy. There are risks to the mother and fetus from untreated pulmonary arterial hypertension ( see Clinical Considerations ). In animal reproduction studies, pregnant rats and rabbits received epoprostenol sodium during organogenesis at exposures of 2.5 and 4.8 times the maximum recommended human dose (MRHD), respectively, and there was no effect on the fetus ( see Data ). The estimated background risk of major birth defects and miscarriage for the indicated population 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/or Embryo/Fetal Risk Pregnant women with untreated pulmonary arterial hypertension are at risk for heart failure, stroke, preterm delivery, and maternal and fetal death. Data Animal Data Embryo-fetal development studies have been performed in rats and rabbits during organogenesis.

Epoprostenol sodium doses up to 100 mcg/kg/day, a dose that was maternally toxic in rabbits but not in rats, (600 mcg/m 2 /day in rats, 2.5 times the MRHD, and 1,180 mcg/m 2 /day in rabbits, 4.8 times the MRHD based on body surface area), had no effect on the fetus. In a postnatal development study, epoprostenol sodium was administered subcutaneously to female rats for 2 weeks prior to mating through weaning and to male rats for 60 days prior to and through mating at a male and female toxic dose of up to 100 mcg/kg/day (600 mcg/m 2 /day, 2.5 times the MRHD based on body surface area). There was no effect on growth and development of the offspring.

Pediatric Use Safety and effectiveness in pediatric patients have not been established.

• A large study evaluating the effect of epoprostenol on survival in NYHA Class III and IV patients with congestive heart failure due to severe left ventricular systolic dysfunction was terminated after an interim analysis of 471 patients revealed a higher mortality in patients receiving epoprostenol plus conventional therapy than in those receiving conventional therapy alone. The chronic use of epoprostenol in patients with congestive heart failure due to severe left ventricular systolic dysfunction is therefore contraindicated. Some patients with pulmonary hypertension have developed pulmonary edema during dose initiation, which may be associated with pulmonary veno-occlusive disease. Epoprostenol should not be used chronically in patients who develop pulmonary edema during dose initiation. Epoprostenol is also contraindicated in patients with known hypersensitivity to the drug or to structurally related compounds.
• Congestive heart failure due to severe left ventricular systolic dysfunction ( 4 )
• Pulmonary edema (4)
• Hypersensitivity to the drug or to structurally related compounds ( 4 )

Signs and symptoms of excessive doses of epoprostenol during clinical trials are the expected dose-limiting pharmacologic effects of epoprostenol, including flushing, headache, hypotension, tachycardia, nausea, vomiting, and diarrhea. Treatment will ordinarily require dose reduction of epoprostenol. One patient with secondary pulmonary hypertension accidentally received 50 mL of an unspecified concentration of epoprostenol.

The patient vomited and became unconscious with an initially unrecordable blood pressure. Epoprostenol was discontinued and the patient regained consciousness within seconds. In clinical practice, fatal occurrences of hypoxemia, hypotension, and respiratory arrest have been reported following overdosage of epoprostenol.

Single intravenous doses of epoprostenol at 10 and 50 mg/kg (2,703 and 27,027 times the recommended acute phase human dose based on body surface area) were lethal to mice and rats, respectively. Symptoms of acute toxicity were hypoactivity, ataxia, loss of righting reflex, deep slow breathing, and hypothermia.