Hepatotoxicity
In clinical studies, Tracleer caused at least 3-fold upper limit of normal (ULN) elevation of liver aminotransferases (ALT and AST) in about 11% of patients, accompanied by elevated bilirubin in a small number of cases. Because these changes are a marker for potential serious hepatotoxicity, serum aminotransferase levels must be measured prior to initiation of treatment and then monthly [see Dosage and Administration (2.4), Warnings and Precautions (5.1)]. In the postmarketing period, in the setting of close monitoring, rare cases of unexplained hepatic cirrhosis were reported after prolonged (> 12 months) therapy with Tracleer in patients with multiple comorbidities and drug therapies. There have also been reports of liver failure. The contribution of Tracleer in these cases could not be excluded.
In at least one case, the initial presentation (after > 20 months of treatment) included pronounced elevations in aminotransferases and bilirubin levels accompanied by non-specific symptoms, all of which resolved slowly over time after discontinuation of Tracleer. This case reinforces the importance of strict adherence to the monthly monitoring schedule for the duration of treatment and the treatment algorithm, which includes stopping Tracleer with a rise of aminotransferases accompanied by signs or symptoms of liver dysfunction [see Dosage and Administration (2.4)].
Elevations in aminotransferases require close attention [see Dosage and Administration (2.4)]. Tracleer should generally be avoided in patients with elevated aminotransferases (> 3 × ULN) at baseline because monitoring for hepatotoxicity may be more difficult. If liver aminotransferase elevations are accompanied by clinical symptoms of hepatotoxicity (such as nausea, vomiting, fever, abdominal pain, jaundice, or unusual lethargy or fatigue) or increases in bilirubin ≥ 2 × ULN, treatment with Tracleer should be stopped. There is no experience with the reintroduction of Tracleer in these circumstances.
Embryo-Fetal Toxicity
Tracleer is likely to cause major birth defects if used by pregnant females based on animal data [see Warnings and Precautions (5.2), Use in Specific Populations (8.1)]. Therefore, pregnancy must be excluded before the start of treatment with Tracleer. Throughout treatment and for one month after stopping Tracleer, females of reproductive potential must use two reliable methods of contraception unless the patient has an intrauterine device (IUD) or tubal sterilization, in which case no other contraception is needed. Hormonal contraceptives, including oral, injectable, transdermal, and implantable contraceptives should not be used as the sole means of contraception because these may not be effective in patients receiving Tracleer [see Drug Interactions (7.2)]. Obtain monthly pregnancy tests.
Co-administration of Tracleer in Patients on Ritonavir
In patients who have been receiving ritonavir for at least 10 days, start Tracleer at the recommended initial dose once daily or every other day based upon individual tolerability [see Cytochrome P450 Drug Interactions (7.1)].
Co-administration of Ritonavir in Patients on Tracleer
Discontinue use of Tracleer at least 36 hours prior to initiation of ritonavir. After at least 10 days following the initiation of ritonavir, resume Tracleer at the recommended initial dose once daily or every other day based upon individual tolerability [see Cytochrome P450 Drug Interactions (7.1)].
Decreased Sperm Counts
An open-label, single-arm, multicenter, safety study evaluated the effect on testicular function of Tracleer 62.5 mg twice daily for 4 weeks, followed by 125 mg twice daily for 5 months. Twenty-five male patients with WHO functional class III and IV PAH and normal baseline sperm count were enrolled. Twenty-three completed the study and 2 discontinued due to adverse events not related to testicular function. There was a decline in sperm count of at least 50% in 25% of the patients after 3 or 6 months of treatment with Tracleer. Sperm count remained within the normal range in all 22 patients with data after 6 months and no changes in sperm morphology, sperm motility, or hormone levels were observed. One patient developed marked oligospermia at 3 months and the sperm count remained low with 2 follow-up measurements over the subsequent 6 weeks. Tracleer was discontinued and after 2 months the sperm count had returned to baseline levels. Based on these findings and preclinical data from endothelin receptor antagonists, it cannot be excluded that endothelin receptor antagonists such as Tracleer have an adverse effect on spermatogenesis.
Decreases in Hemoglobin and Hematocrit
Treatment with Tracleer can cause a dose-related decrease in hemoglobin and hematocrit. It is recommended that hemoglobin concentrations be checked after 1 and 3 months, and every 3 months thereafter. If a marked decrease in hemoglobin concentration occurs, further evaluation should be undertaken to determine the cause and need for specific treatment.
The overall mean decrease in hemoglobin concentration for adult Tracleer-treated patients was 0.9 g/dL (change to end of treatment). Most of this decrease of hemoglobin concentration was detected during the first few weeks of Tracleer treatment and hemoglobin levels stabilized by 4–12 weeks of Tracleer treatment. In placebo-controlled studies of all uses of Tracleer, marked decreases in hemoglobin (> 15% decrease from baseline resulting in values < 11 g/dL) were observed in 6% of Tracleer-treated patients and 3% of placebo-treated patients. In patients with PAH treated with doses of 125 and 250 mg twice daily, marked decreases in hemoglobin occurred in 3% compared to 1% in placebo-treated patients.
A decrease in hemoglobin concentration by at least 1 g/dL was observed in 57% of Tracleer-treated patients as compared to 29% of placebo-treated patients. In 80% of those patients whose hemoglobin decreased by at least 1 g/dL, the decrease occurred during the first 6 weeks of Tracleer treatment.
During the course of treatment, the hemoglobin concentration remained within normal limits in 68% of Tracleer-treated patients compared to 76% of placebo patients. The explanation for the change in hemoglobin is not known, but it does not appear to be hemorrhage or hemolysis.
In a pooled analysis of pediatric patients (N=100) with PAH treated with Tracleer, a decrease in hemoglobin levels to < 10 g/dL from baseline was reported in 11% of patients. There was no decrease to < 8 g/dL.
Risk Summary
Based on data from animal reproduction studies, Tracleer may cause fetal harm, including birth defects and fetal death, when administered to a pregnant female and is contraindicated during pregnancy [see Contraindications (4.1)]. There are limited data on Tracleer use in pregnant women. In animal reproduction studies, oral administration of bosentan to pregnant rats at 2-times the maximum recommended human dose (MRHD) on a mg/m2 basis caused teratogenic effects in rats, including malformations of the head, mouth, face, and large blood vessels [see Animal Data]. Advise pregnant women of the potential risk to a fetus.
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 2-4% and 15-20%, respectively.
Data
Animal Data
Bosentan was teratogenic in rats given oral doses two times the MRHD (on a mg/m2 basis). In an embryo-fetal toxicity study in rats, bosentan showed dose-dependent teratogenic effects, including malformations of the head, mouth, face and large blood vessels. Bosentan increased stillbirths and pup mortality at oral doses 2 and 10 times the MRHD (on a mg/m2 basis). Although birth defects were not observed in rabbits given oral doses of up to the equivalent of 10.5 g/day in a 70 kg person, plasma concentrations of bosentan in rabbits were lower than those reached in the rat. The similarity of malformations induced by bosentan and those observed in endothelin-1 knockout mice and in animals treated with other endothelin receptor antagonists indicates that embryo-fetal toxicity is a class effect of these drugs.
Risk Summary
There are no data on the presence of bosentan in human milk, the effects on the breastfed infant, or the effect on milk production. Because of the potential for serious adverse reactions, such as fluid retention and hepatotoxicity, in breastfed infants from Tracleer, advise women not to breastfeed during treatment with Tracleer.
Pregnancy Testing
Verify the pregnancy status of females of reproductive potential prior to initiating Tracleer, monthly during treatment and one month after stopping treatment with Tracleer. The patient should contact her physician immediately for pregnancy testing if onset of menses is delayed or pregnancy is suspected. If the pregnancy test is positive, the physician and patient must discuss the risks to her, the pregnancy, and the fetus.
Contraception
Drug interaction studies show that bosentan reduces serum levels of the estrogen and progestin in oral contraceptives. Based on these findings, hormonal contraceptives (including oral, injectable, transdermal, and implantable contraceptives) may be less effective for preventing pregnancy in patients using Tracleer and should not be used as a patient's only contraceptive method [see Drug Interactions (7.2)]. Females of reproductive potential using Tracleer must use two acceptable methods of contraception during treatment and for 1 month after treatment with Tracleer. Patients may choose one highly effective form of contraception (intrauterine devices (IUD) or tubal sterilization) or a combination of methods (hormone method with a barrier method or two barrier methods). If a partner's vasectomy is the chosen method of contraception, a hormone or barrier method must be used along with this method. Counsel patients on pregnancy planning and prevention, including emergency contraception, or designate counseling by another healthcare provider trained in contraceptive counseling [see Boxed Warning].
Infertility
Males
Decreased sperm counts have been observed in patients receiving Tracleer. Based on these findings and findings in animals, Tracleer may impair fertility in males of reproductive potential. It is not known whether effects on fertility would be reversible [see Warnings and Precautions (5.6), Adverse Reactions (6.1), Nonclinical Toxicology (13.1)].
Juvenile Animal Toxicity Data
In a juvenile rat toxicity study, rats were treated from Day 4 postpartum to adulthood (Day 69 postpartum). Decreased body weights, absolute weights of testes and epididymides, and reduced number of sperm in epididymides were observed after weaning. No effect on testis histology or sperm morphology and function was seen. The NOAEL was 4 times (at Day 4 postpartum) and 2 times (Day 69 postpartum) the human therapeutic exposure, respectively.
No effects on general development, sensory, cognitive function and reproductive performance were detected at the highest dose tested in juvenile rats, 7 times the therapeutic exposure in children with PAH.
General
After oral administration, maximum plasma concentrations of bosentan are attained within 3–5 hours and the terminal elimination half-life is about 5 hours in healthy adult subjects. The exposure to bosentan after intravenous and oral administration is about twice as high in adult patients with PAH as it is in healthy adult subjects.
In a relative bioavailability study in healthy adults, the peak plasma concentration and area under the plasma concentration-time curve for bosentan are on an average 14% and 11%, respectively, lower following administration of the oral dispersible tablet compared to the film-coated tablet.
Absorption
The absolute bioavailability of bosentan in normal volunteers is about 50% and is unaffected by food.
Bosentan is highly bound (> 98%) to plasma proteins, mainly albumin. Bosentan does not penetrate into erythrocytes. The volume of distribution is about 18 L.
Elimination
Metabolism
Bosentan has three metabolites, one of which is pharmacologically active and may contribute 10%–20% of the effect of bosentan. Bosentan is an inducer of CYP2C9 and CYP3A and possibly also of CYP2C19. Upon multiple oral dosing, plasma concentrations in healthy adults decrease gradually to 50-65% of those seen after single dose administration, probably the effect of auto-induction of the metabolizing liver enzymes. Steady-state is reached within 3-5 days.
Excretion
Bosentan is eliminated by biliary excretion following metabolism in the liver. Less than 3% of an administered oral dose is recovered in urine. Total clearance after a single intravenous dose is about 4 L/h in patients with PAH.
Specific Populations
Pediatrics
The average plasma exposure to bosentan at steady state (AUCss) in pediatric patients with PAH aged 3 to 15 years treated with 31.25, 62.5 or 125 mg (approximately 2 mg/kg) film-coated tablet twice daily is 37% lower than that observed in adult patients with PAH receiving 125 mg film-coated tablet twice daily. Following administration of 4 mg/kg twice daily doses of dispersible tablet in patients with PAH aged 2 to 11 years, the average systemic exposure to bosentan at steady state is similar to that observed with 2 mg/kg. The average exposure to bosentan in these pediatric patients was approximately half the exposure in adult patients treated with 125 mg film-coated tablets twice daily.
The exposure to bosentan at 2 mg/kg three times daily dosing of dispersible tablet is similar to that of 2 mg/kg twice daily dosing in patients with PAH aged 3 months to 12 years.
Based on these findings, exposure to bosentan reaches a plateau at lower doses in pediatric patients than in adults, and doses higher than 2 mg/kg twice daily do not increase the exposure to bosentan in pediatric patients.
Hepatic Impairment
In vitro and in vivo evidence showing extensive hepatic metabolism of bosentan suggests that liver impairment could significantly increase exposure to bosentan. In a study comparing 8 patients with mild liver impairment (Child-Pugh Class A) to 8 controls, the single- and multiple-dose pharmacokinetics of bosentan were not altered in patients with mild hepatic impairment.
In another small (N=8) pharmacokinetic study, the steady-state AUC of bosentan was on average 4.7 times higher and the active metabolite Ro 48-5033 was 12.4 times higher in 5 patients with moderately impaired liver function (Child-Pugh Class B) and PAH associated with portal hypertension than in 3 patients with normal liver function and PAH of other etiologies.
The pharmacokinetics of Tracleer have not been evaluated in patients with severe liver impairment (Child-Pugh Class C) [see Dosage and Administration (2.2), Warnings and Precautions (5.1), Use in Specific Populations (8.6)].
Renal Impairment
In patients with severe renal impairment (creatinine clearance 15–30 mL/min), plasma concentrations of bosentan were essentially unchanged and plasma concentrations of the three metabolites were increased about 2-fold compared to subjects with normal renal function. These differences do not appear to be clinically important.
Drug Interactions
Ketoconazole
Co-administration of bosentan 125 mg twice daily and ketoconazole, a potent CYP3A inhibitor, increased the plasma concentrations of bosentan by approximately 100% in normal volunteers. No dose adjustment of Tracleer is necessary, but increased effects of Tracleer should be considered.
Warfarin
Co-administration of bosentan 500 mg twice daily for 6 days in normal volunteers decreased the plasma concentrations of both S-warfarin (a CYP2C9 substrate) and R-warfarin (a CYP3A substrate) by 29 and 38%, respectively. Clinical experience with concomitant administration of Tracleer and warfarin in patients with PAH did not show clinically relevant changes in INR or warfarin dose (baseline vs. end of the clinical studies), and the need to change the warfarin dose during the trials due to changes in INR or due to adverse events was similar among Tracleer- and placebo-treated patients.
Digoxin, Nimodipine, and Losartan
Bosentan has no significant pharmacokinetic interactions with digoxin and nimodipine, and losartan has no significant effect on plasma levels of bosentan.
Sildenafil
In normal volunteers, co-administration of multiple doses of 125 mg twice daily bosentan and 80 mg three times daily sildenafil resulted in a reduction of sildenafil plasma concentrations by 63% and increased bosentan plasma concentrations by 50%. The changes in plasma concentrations were not considered clinically relevant and dose adjustments are not necessary. This recommendation holds true when sildenafil is used for the treatment of PAH or erectile dysfunction.
Figure 3. CYP Induction-mediated effect of bosentan on other drugs
Figure 4. Effects of other drugs on bosentan
Carcinogenesis and Mutagenesis
Two years of dietary administration of bosentan to mice produced an increased incidence of hepatocellular adenomas and carcinomas in males at doses as low as 450 mg/kg/day (about 8 times the maximum recommended human dose [MRHD] of 125 mg twice daily, on a mg/m2 basis). In the same study, doses greater than 2000 mg/kg/day (about 32 times the MRHD) were associated with an increased incidence of colon adenomas in both males and females. In rats, dietary administration of bosentan for two years was associated with an increased incidence of brain astrocytomas in males at doses as low as 500 mg/kg/day (about 16 times the MRHD). In a comprehensive battery of in vitro tests (the microbial mutagenesis assay, the unscheduled DNA synthesis assay, the V-79 mammalian cell mutagenesis assay, and human lymphocyte assay) and an in vivo mouse micronucleus assay, there was no evidence for any mutagenic or clastogenic activity of bosentan.
Impairment of Fertility/Testicular Function
The development of testicular tubular atrophy and impaired fertility has been linked with the chronic administration of certain endothelin receptor antagonists in rodents.
Treatment with bosentan at oral doses of up to 1500 mg/kg/day (50 times the MRHD on a mg/m2 basis) or intravenous doses up to 40 mg/kg/day had no effects on sperm count, sperm motility, mating performance or fertility in male and female rats. An increased incidence of testicular tubular atrophy was observed in rats given bosentan orally at doses as low as 125 mg/kg/ day (about 4 times the MRHD and the lowest doses tested) for two years but not at doses as high as 1500 mg/kg/day (about 50 times the MRHD) for 6 months. Effects on sperm count and motility were evaluated only in the much shorter duration fertility studies in which males had been exposed to the drug for 4-6 weeks. An increased incidence of tubular atrophy was not observed in mice treated for 2 years at doses up to 4500 mg/kg/day (about 75 times the MRHD) or in dogs treated up to 12 months at doses up to 500 mg/kg/day (about 50 times the MRHD).
WHO Functional Class III-IV
Two randomized, double-blind, multi-center, placebo-controlled trials were conducted in 32 and 213 patients. The larger study (BREATHE-1) compared 2 doses (125 mg twice daily and 250 mg twice daily) of Tracleer with placebo. The smaller study (Study 351) compared 125 mg twice daily with placebo. Patients had severe (WHO functional Class III–IV) PAH: idiopathic or heritable PAH (72%) or PAH associated with scleroderma or other connective tissue diseases (21%), or to autoimmune diseases (7%). There were no patients with PAH associated with other conditions such as HIV disease or recurrent pulmonary emboli.
In both studies, Tracleer or placebo was added to patients' current therapy, which could have included a combination of digoxin, anticoagulants, diuretics, and vasodilators (e.g., calcium channel blockers, ACE inhibitors), but not epoprostenol. Tracleer was given at a dose of 62.5 mg twice daily for 4 weeks and then at 125 mg twice daily or 250 mg twice daily for either 12 (BREATHE-1) or 8 (Study 351) additional weeks. The primary study endpoint was 6-minute walk distance. In addition, symptoms and functional status were assessed. Hemodynamic measurements were made at 12 weeks in Study 351.
The mean age was about 49 years. About 80% of patients were female, and about 80% were Caucasian. Patients had been diagnosed with pulmonary hypertension for a mean of 2.4 years.
Submaximal Exercise Ability
Results of the 6-minute walk distance at 3 months (Study 351) or 4 months (BREATHE-1) are shown in Table 4.
Table 4. Effects of Tracleer on 6-minute walk distance | BREATHE-1 | Study 351 |
|---|
| Tracleer | Tracleer | Placebo | Tracleer | Placebo |
|---|
| 125 mg twice daily | 250 mg twice daily | (n = 69) | 125 mg twice daily | (n = 11) |
|---|
| (n = 74) | (n = 70) | | (n = 21) | |
|---|
| Distance in meters: mean ± standard deviation. Changes are to week 16 for BREATHE-1 and to week 12 for Study 351. |
| Baseline | 326 ± 73 | 333 ± 75 | 344 ± 76 | 360 ± 86 | 355 ± 82 |
| End point | 353 ± 115 | 379 ± 101 | 336 ± 129 | 431 ± 66 | 350 ± 147 |
| Change from baseline | 27 ± 75 | 46 ± 62 | -8 ± 96 | 70 ± 56 | -6 ± 121 |
| Placebo – subtracted | 35 p=0.01; by Wilcoxon; | 54 p=0.0001; by Wilcoxon; | | 76 p=0.02; by Student's t-test. | |
In both trials, treatment with Tracleer resulted in a significant increase in exercise ability. The improvement in walk distance was apparent after 1 month of treatment (with 62.5 mg twice daily) and fully developed by about 2 months of treatment (Figure 5). It was maintained for up to 7 months of double-blind treatment. Walking distance was somewhat greater with 250 mg twice daily, but the potential for increased hepatotoxicity causes this dose not to be recommended [see Dosage and Administration (2.1)]. There were no apparent differences in treatment effects on walk distance among subgroups analyzed by demographic factors, baseline disease severity, or disease etiology, but the studies had little power to detect such differences.
Figure 5. Mean Change in 6-min Walk Distance (BREATHE-1)
Change from baseline in 6-minute walking distance from start of therapy to week 16 in the placebo and combined Tracleer (125 mg twice daily and 250 mg twice daily) groups. Values are expressed as mean ± standard error of the mean.
Hemodynamic Changes
Invasive hemodynamic parameters were assessed in Study 351. Treatment with Tracleer led to a significant increase in cardiac index (CI) associated with a significant reduction in pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), and mean right atrial pressure (RAP) (Table 5).
The relationship between hemodynamic effects and improvements in 6-minute walk distance is unknown.
Table 5: Change from Baseline to Week 12: Hemodynamic Parameters | Tracleer 125 mg twice daily | | Placebo |
|---|
| Values shown are means ± SD |
| CI (L/min/m2) | n=20 | | n=10 |
| Baseline | 2.35±0.73 | | 2.48±1.03 |
| Absolute Change | 0.50±0.46 | | -0.52±0.48 |
| Treatment Effect | | 1.02 p≤0.001; | |
| Mean PAP (mmHg) | n=20 | | n=10 |
| Baseline | 53.7±13.4 | | 55.7±10.5 |
| Absolute Change | -1.6±5.1 | | 5.1±8.8 |
| Treatment Effect | | -6.7 p<0.02 | |
| PVR (dyn∙sec∙cm-5) | n=19 | | n=10 |
| Baseline | 896±425 | | 942±430 |
| Absolute Change | -223±245 | | 191±235 |
| Treatment Effect | | -415 | |
| Mean RAP (mmHg) | n=19 | | n=10 |
| Baseline | 9.7±5.6 | | 9.9±4.1 |
| Absolute Change | -1.3±4.1 | | 4.9±4.6 |
| Treatment Effect | | -6.2 | |
Symptoms and Functional Status
Symptoms of PAH were assessed by Borg dyspnea score, WHO functional class, and rate of "clinical worsening." Clinical worsening was assessed as the sum of death, hospitalizations for PAH, discontinuation of therapy because of PAH, and need for epoprostenol. There was a significant reduction in dyspnea during walk tests (Borg dyspnea score), and significant improvement in WHO functional class in Tracleer-treated patients. There was a significant reduction in the rate of clinical worsening (Table 6 and Figure 6). Figure 6 shows the log-rank test reflecting clinical worsening over 28 weeks.
Table 6. Incidence of Clinical Worsening, Intent To Treat Population | BREATHE-1 | | Study 351 | |
|---|
| Tracleer 125/250 mg twice daily (n = 144) | Placebo (n = 69) | Tracleer 125 mg twice daily (n = 21) | Placebo (n = 11) |
|---|
| Note: Patients may have had more than one reason for clinical worsening. |
| Patients with clinical worsening [n (%)] | 9 (6%) p=0.0015 vs. placebo by log-rank test. There was no relevant difference between the 125 mg and 250 mg twice daily groups. | 14 (20%) | 0 (0%) p=0.033 vs. placebo by Fisher's exact test. | 3 (27%) |
| Death | 1 (1%) | 2 (3%) | 0 (0%) | 0 (0%) |
| Hospitalization for PAH | 6 (4%) | 9 (13%) | 0 (0%) | 3 (27%) |
| Discontinuation due to worsening of PAH | 5 (3%) | 6 (9%) | 0 (0%) | 3 (27%) |
| Receipt of epoprostenol Receipt of epoprostenol was always a consequence of clinical worsening. | 4 (3%) | 3 (4%) | 0 (0%) | 3 (27%) |
Figure 6. Time to Clinical Worsening (BREATHE-1)
Time from randomization to clinical worsening with Kaplan-Meier estimate of the proportions of failures in BREATHE-1. All patients (n=144 in the Tracleer group and n=69 in the placebo group) participated in the first 16 weeks of the study. A subset of this population (n=35 in the Tracleer group and 13 in the placebo group) continued double-blind therapy for up to 28 weeks.
WHO Functional Class II
In a randomized, double-blind, multicenter, placebo-controlled trial, 185 mildly symptomatic PAH patients with WHO Functional Class II (mean baseline 6-minute walk distance of 443 meters) received Tracleer 62.5 mg twice daily for 4 weeks followed by 125 mg twice daily (n = 93), or placebo (n = 92) for 6 months. Enrolled patients were treatment-naïve (n = 156) or on a stable dose of sildenafil (n = 29). The coprimary endpoints were change from baseline to month 6 in PVR and 6-minute walk distance. Time to clinical worsening (assessed as the sum of death, hospitalization due to PAH complications, or symptomatic progression of PAH), Borg dyspnea index, change in WHO functional class and hemodynamics were assessed as secondary endpoints.
Compared with placebo, Tracleer treatment was associated with a reduced incidence of worsening of at least one functional class (3% Tracleer vs. 13% placebo, p = 0.03), and improvement in hemodynamic variables (PVR, mPAP, TPR, cardiac index, and SVO2; p < 0.05). The +19 m mean (+14 m median) increase in 6-minute walk distance with Tracleer vs. placebo was not significant (p = 0.08). There was a significant delay in time to clinical worsening (first seen primarily as symptomatic progression of PAH) with Tracleer compared with placebo (hazard ratio 0.2, p = 0.01). Findings were consistent in strata with or without treatment with sildenafil at baseline.
Long-term Treatment of PAH
Long-term follow-up of patients with Class III and IV PAH who were treated with Tracleer in open-label extensions of trials (N=235) showed that 93% and 84% of patients were still alive at 1 and 2 years, respectively, after the start of treatment.
These uncontrolled observations do not allow comparison with a group not given Tracleer and cannot be used to determine the long-term effect of Tracleer on mortality.
Pediatric Studies
The efficacy of bosentan was evaluated in an open-label, uncontrolled study in 19 pediatric patients with PAH aged 3 to 15 years. Patients had primary pulmonary hypertension (n = 10) or PAH related to congenital heart diseases (9 patients) and were WHO functional class II (n = 15, 79%) or class III (n = 4; 21%) at baseline. Patients were dosed with bosentan at approximately 2 mg/kg twice daily (body weight adjusted dose, corresponding to the recommended adult dose) [see Dosage and Administration (2.1)] for 12 weeks. Half of the patients in each group were already being treated with intravenous epoprostenol and the dose of epoprostenol remained constant for the duration of the study.
Hemodynamics were measured in 17 patients (Table 7). The mean decrease in PVR was 389 dyn∙sec∙cm-5, which was similar to the effect seen in adults. Hemodynamic improvements from baseline were similar with or without co-administration of epoprostenol.
Table 7: Change from Baseline to Week 12: Hemodynamic Parameters | Tracleer 2 mg/kgtwice daily |
|---|
| Values shown are means ± SD |
| CI (L/min/m2) | n=17 |
| Baseline | 4.0±1.5 |
| Absolute Change | 0.5±1.4 |
| Mean PAP (mmHg) | n=18 |
| Baseline | 60±18 |
| Absolute Change | -8±9 |
| PVR (dyn∙sec∙cm-5) | n=17 |
| Baseline | 1195±755 |
| Absolute Change | -389±616 |
| Mean RAP (mmHg) | n=18 |
| Baseline | 6.1±2.7 |
| Absolute Change | -0.5±2.3 |
Pulmonary Arterial Hypertension in Adults related to Congenital Heart Disease with Left-to-Right Shunts
A small study (N=54) and its open-label extension (N=37) of up to 40 weeks in adult patients with Eisenmenger physiology demonstrated effects of Tracleer on exercise and safety that were similar to those seen in other trials in patients with PAH (WHO Group 1).
Manufactured for:
Actelion Pharmaceuticals US, Inc.
South San Francisco, CA 94080, USA
ACT20170823
Restricted access
Advise the patient that Tracleer is only available through a restricted access program called the Tracleer REMS Program.
As a component of the Tracleer REMS, prescribers must review the contents of the Tracleer Medication Guide with the patient before initiating Tracleer.
Instruct patients that the risks associated with Tracleer include:
- Hepatotoxicity
Discuss with the patient the requirement to measure serum aminotransferases monthly. - Embryo-fetal toxicity
Educate and counsel female patients of reproductive potential about the need to use reliable methods of contraception during treatment with Tracleer and for one month after treatment discontinuation. Females of reproductive potential must have monthly pregnancy tests and must use two different forms of contraception while taking Tracleer and for one month after discontinuing Tracleer [see Use in Specific Populations (8.1)].
Females who have intrauterine devices (IUD) or tubal sterilization can use these contraceptive methods alone. Patients should be instructed to immediately contact their physician if they suspect they may be pregnant. Patients should seek additional contraceptive advice from a gynecologist or similar expert as needed.
Educate and counsel females of reproductive potential on the use of emergency contraception in the event of unprotected sex or contraceptive failure.
Advise pre-pubertal females to report any changes in their reproductive status immediately to her prescriber.
Advise patients to contact their gynecologist or healthcare provider if they want to change the form of birth control which is used to ensure that another acceptable form of birth control is selected.
Advise the patient that Tracleer is available only from specialty pharmacies that are enrolled in the Tracleer REMS Program.
Patients must sign the Tracleer Patient Enrollment and Consent Form to confirm that they understand the risks of Tracleer. - Lactation
Advise women not to breastfeed during treatment with TRACLEER [see Use in Specific Populations (8.2)]. - Infertility
Advise males of reproductive potential that TRACLEER may impair fertility [see Warnings and Precautions (5.6), Adverse Reactions (6.1), Use in Specific Populations (8.3) and Nonclinical Toxicology (13.1)]. - Phenylketonurics
Tracleer dispersable tablets contain phenylalanine, a component of aspartame. Each dispersible tablet contains 1.87 mg of phenylalanine.
Other Risks Associated with Tracleer
Instruct patients that the risks associated with Tracleer also include the following:
Decreases in hemoglobin and hematocrit – advise patients of the importance of hemoglobin testing
Decreases in sperm count
Fluid retention
Administration Considerations
Advise patients that Tracleer dispersible tablets should not be split into quarters.