Effects of dose and age on adverse events associated with tadalafil in the treatment of pulmonary arterial hypertension.

There are limited data on the management of pulmonary arterial hypertension (PAH) in the elderly; therefore, this analysis compared the safety and efficacy of tadalafil between patients ≥65 and <65 years old. This was a post hoc analysis of the randomized, double-blind, placebo-controlled phase 3 Pulmonary Arterial Hypertension and Response to Tadalafil (PHIRST-1) study. Patients who completed the 16-week study or who discontinued because of clinical worsening and were not receiving tadalafil 40 mg were eligible for a long-term, open-label extension study. Adverse events (AEs) and efficacy outcomes were assessed in patients ≥65 versus <65 years old, and the dose dependency of common AEs was determined. Twenty-eight percent (112 of 405) of patients were ≥65 years of age (mean in this subset, 72 ± 5 years). Compared with younger patients, elderly patients were more likely to be World Health Organization functional class III/IV (75% vs. 65%, respectively) and to have lower exercise capacity as assessed by 6-minute walk distance (6MWD; mean, 299 vs. 366 m). Compared with placebo, tadalafil increased 6MWD by a mean of 35 and 43 m in patients ≥65 and <65 years, respectively. Common AEs (including headache, dyspepsia, and myalgia) were similar in both groups and tended to decrease in incidence with longer treatment duration. No differences in AEs were observed between elderly patients who received tadalafil 20 or 40 mg. In conclusion, the safety and efficacy of tadalafil for treatment of PAH are similar between elderly patients and patients <65 years old.

Oral treprostinil for the treatment of pulmonary arterial hypertension in patients receiving background endothelin receptor antagonist and phosphodiesterase type 5 inhibitor therapy (the FREEDOM-C2 study): a randomized controlled trial.

BACKGROUND: Treprostinil is a stable prostacyclin analog approved for the treatment of pulmonary arterial hypertension (PAH) as parenteral or inhaled therapy. Treprostinil diolamine, a sustained-release oral formulation of treprostinil, was studied to determine whether it could provide a more convenient prostacyclin treatment option for patients with less severe PAH. The objective of this study was to evaluate the efficacy and safety of oral treprostinil in patients with PAH receiving stable background endothelin receptor antagonist (ERA), phosphodiesterase type 5 inhibitor (PDE-5I) therapy, or both. METHODS: A 16-week, multicenter, double-blind, placebo-controlled study in 310 patients with PAH compared bid administration of oral treprostinil (n = 157) with placebo (n = 153). The primary end point was change in 6-min walk distance at week 16. Secondary efficacy end points were World Health Organization functional class, Borg dyspnea score, dyspnea-fatigue index, signs and symptoms of PAH, and clinical worsening. RESULTS: One hundred thirty-two patients (84%) receiving oral treprostinil and 138 (90%) receiving placebo completed the study. The mean ± SD dose of oral treprostinil at week 16 was 3.1 ± 1.9 mg bid. The Hodges-Lehmann placebo-corrected median difference in 6MWD at week 16 was 10.0 m (95% CI, -2 to 22 m; P = .089). There were no significant changes in secondary end points. The most common adverse events associated with oral treprostinil were headache (71%), diarrhea (55%), nausea (46%), flushing (35%), and jaw pain (25%). CONCLUSIONS: The addition of oral treprostinil to background ERA and PDE-5I therapy did not result in a statistically significant improvement in exercise capacity. Side effects were common but tolerated by most subjects. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00887978; URL: www.clinicaltrials.gov.

Treatment satisfaction is associated with improved quality of life in patients treated with inhaled treprostinil for pulmonary arterial hypertension.

BACKGROUND: Patient treatment satisfaction is likely to be a highly relevant outcome measure in pulmonary arterial hypertension (PAH), a condition for which the benefits of treatment must be weighed against frequent, undesirable side effects, inconvenience, and complications associated with therapy. In this study, we sought to evaluate the psychometric properties of a patient-reported treatment satisfaction measure and its relationship to quality of life (QoL) among patients transitioning from inhaled iloprost (iILO) to inhaled treprostinil (iTRE). METHODS: We studied treatment satisfaction among 66 subjects with PAH in a single-arm, open-label, multi-center trial of iTRE following transition from iILO. Treatment satisfaction was assessed using the Treatment Satisfaction Questionnaire for Medication (TSQM, version 1.4) administered to subjects immediately before and 12 weeks after transition of inhaled therapy. The TSQM is comprised of 4 domains: effectiveness, side effects, convenience, and global satisfaction. Scores range from 0 to 100 with higher scores indicating greater satisfaction. Six-minute walk distance (6MWD), functional class, adverse events, drug administration time, and PAH-specific QoL (CAMPHOR) were concurrently assessed. RESULTS: Domains of the TSQM demonstrated evidence of strong internal consistency at baseline and at 12 weeks (Cronbach α = 0.88-0.93). Transition from iILO to iTRE was associated with an improvement in 3 of 4 TSQM domains: effectiveness (+20 ± 21, p < 0.0001), side effects (0 ± 22, p = 0.97), convenience (+39 ± 26, p < 0.0001), and global satisfaction (+20 ± 24, p = 0.0005). Change in effectiveness scores correlated with change in 6MWD (r = 0.43, p = 0.0004) and side effects scores at 12 weeks correlated inversely with number of severity-weighted treatment-emergent adverse events (r = -0.44, p = 0.0002). In multiple regression models adjusted for baseline characteristics, changes in effectiveness and convenience satisfaction scores were significantly associated with improvement in PAH-specific QoL (p = 0.002 and p = 0.01). CONCLUSIONS: The TSQM demonstrated acceptable performance characteristics in patients with PAH. Changes in treatment satisfaction resulting from transitioning from iILO to iTRE were associated with improvements in PAH-specific QoL.

Efficacy and safety of oral treprostinil monotherapy for the treatment of pulmonary arterial hypertension: a randomized, controlled trial.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a progressive, fatal disease with no cure. Parenteral and inhaled prostacyclin analogue therapies are effective for the treatment of PAH, but complicated administration requirements can limit the use of these therapies in patients with less severe disease. This study was designed to evaluate the safety and efficacy of the oral prostacyclin analogue treprostinil diolamine as initial treatment for de novo PAH. METHODS AND RESULTS: Three hundred forty-nine patients (intent-to-treat population) not receiving endothelin receptor antagonist or phosphodiesterase type-5 inhibitor background therapy were randomized (treprostinil, n=233; placebo, n=116). The primary analysis population (modified intent-to-treat) included 228 patients (treprostinil, n=151; placebo, n=77) with access to 0.25-mg treprostinil tablets at randomization. The primary end point was change from baseline in 6-minute walk distance at week 12. Secondary end points included Borg dyspnea index, clinical worsening, and symptoms of PAH. The week 12 treatment effect for 6-minute walk distance (modified intent-to-treat population) was 23.0 m (P=0.0125). For the intent-to-treat population, 6-minute walk distance improvements were observed at peak (26.0 m; P=0.0001) and trough (17.0 m; P=0.0025) plasma study drug concentrations. Other than an improvement in the combined 6-minute walk distance/Borg dyspnea score, there were no significant changes in secondary end points. Oral treprostinil therapy was generally well tolerated; the most common adverse events (intent-to-treat) were headache (69%), nausea (39%), diarrhea (37%), and pain in jaw (25%). CONCLUSIONS: Oral treprostinil improves exercise capacity in PAH patients not receiving other treatment. Oral treprostinil could provide a convenient, first-line prostacyclin treatment option for PAH patients not requiring more intensive therapy. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00325403.

Oral treprostinil for the treatment of pulmonary arterial hypertension in patients on background endothelin receptor antagonist and/or phosphodiesterase type 5 inhibitor therapy (the FREEDOM-C study): a randomized controlled trial.

BACKGROUND: Infused and inhaled treprostinil are effective for treatment of pulmonary arterial hypertension (PAH), although their administration routes have limitations. This study assessed the efficacy and safety of bid oral sustained-release treprostinil in the treatment of PAH with a concomitant endothelin receptor antagonist (ERA) and/or phosphodiesterase type 5 inhibitor. METHODS: A 16-week, multicenter, double-blind, placebo-controlled study was conducted in 350 patients with PAH randomized to placebo or oral treprostinil. All patients were stable on background ERA, PDE-5 inhibitor, or both. Primary end point was Hodges-Lehmann placebo-corrected median difference in change from baseline 6-min walk distance (6MWD) at week 16. Secondary end points included time to clinical worsening, change in World Health Organization functional class, Borg dyspnea score, and dyspnea fatigue index score. RESULTS: Thirty-nine patients (22%) receiving oral treprostinil and 24 patients (14%) receiving placebo discontinued the study. Placebo-corrected median difference in change from baseline 6MWD at week 16 was 11 m (P = .07). Improvements in dyspnea fatigue index score (P = .01) and combined 6MWD and Borg dyspnea score (P = .01) were observed with oral treprostinil vs placebo treatment. Patients who achieved a week-16 bid oral treprostinil dose of 1.25 to 3.25 mg and 3.5 to 16 mg experienced a greater change in 6MWD (18 m and 34 m, respectively) than patients who achieved a bid dose of < 1 mg or discontinued because of adverse events (4 m). CONCLUSIONS: The primary end point of improvement in 6MWD at week 16 did not achieve significance. This study enhanced understanding of oral treprostinil titration and dosing, which has set the stage for additional studies. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00325442; URL: www.clinicaltrials.gov.

The effect of diluent pH on bloodstream infection rates in patients receiving IV treprostinil for pulmonary arterial hypertension.

BACKGROUND: Recent studies have reported an increase in catheter-related bloodstream infections (BSIs) and gram-negative BSIs among patients with pulmonary arterial hypertension treated with IV treprostinil. One possible explanation is the neutral pH of the treprostinil diluent compared with the basic pH of epoprostenol. We hypothesized that administering IV treprostinil with epoprostenol diluent will lower the rate of gram-negative BSI. METHODS: We prospectively enrolled patients treated with IV treprostinil and changed the diluent from native diluent to epoprostenol diluent. We compared the incidence of BSI and gram-negative BSI between those receiving IV treprostinil with epoprostenol diluent (n = 25) and those actively receiving IV epoprostenol (n = 61), as well as with a cohort of patients who received IV treprostinil in native diluent (n = 34). Incidence rates of BSI were expressed as a fraction of 1,000 medicine treatment days. RESULTS: There were similar rates of BSI in those treated with treprostinil with epoprostenol diluent and those treated with epoprostenol (0.32 of 1,000 vs 0.40 of 1,000; P = .79). Also, there were similar rates of gram-negative BSI in these two cohorts (0.08 of 1,000 vs 0.20 of 1,000; P = .46). BSI rates were not statistically different between those treated with treprostinil with epoprostenol diluent and those treated with treprostinil (0.32 of 1,000 vs 0.90 of 1,000; P = .06). However, gram-negative BSIs were significantly lower in patients treated with treprostinil with epoprostenol diluent than in those treated with treprostinil (0.08 of 1,000 vs 0.71 of 1,000, respectively; P = .01). CONCLUSIONS: Patients treated with treprostinil with epoprostenol diluent have a lower incidence of gram-negative BSI than do those treated with treprostinil and a similar rate to those treated with epoprostenol. Changing the diluent of treprostinil to epoprostenol diluent, in combination with the use of water-tight seals throughout the delivery system, appears to be an effective safety measure.

Prognostic factors associated with increased survival in patients with pulmonary arterial hypertension treated with subcutaneous treprostinil in randomized, placebo-controlled trials.

BACKGROUND: Because of the challenges associated with conducting large survival studies of patients with pulmonary arterial hypertension (PAH), we analyzed the surrogate markers predictive of long-term survival in a large cohort of patients treated with subcutaneous treprostinil. METHODS: A retrospective review was conducted using data from a total of 811 patients with New York Heart Association Functional Class (NYHA FC) II to IV PAH, who were treated with subcutaneous treprostinil. Patient baseline disease and on-treatment parameters were analyzed by uni- and multivariate analyses for predictive value of 3-year survival with PAH. RESULTS: Among the baseline disease-related factors analyzed, there was a significantly higher risk of death (p < 0.001) associated with connective tissue disease-associated PAH relative to idiopathic PAH (hazard ratio for death [HR] 1.93), NYHA FC IV vs III (HR 2.31), pulmonary vascular resistance index (PVRI) >30 vs ≤16 mm Hg/liter/min/m(2) (HR 2.44) and mixed venous oxygen saturation (SVO(2)) ≤55% vs >55%. The 6-minute walk distance (6MWD) of ≤295 m after 12 weeks of treprostinil treatment was associated with reduced survival at 3 years (58%). A ≥20-m increase from baseline in 6MWD was associated with greater survival (80%) vs smaller walk increments (69%; p = 0.039). Treprostinil dose of ≥40 ng/kg/min (p < 0.001) and every 10-ng/kg/min dose increase (p = 0.009) resulted in improved long-term survival. In a multivariate analysis, only SVO(2), 6MWD and treprostinil dose were significant on-treatment predictors (p < 0.02) of survival. CONCLUSIONS: Disease etiology, baseline factors (NYHA FC, PVRI and SVO(2)) and on-treatment factors (6MWD, SVO(2) and treprostinil dose) were predictors of survival in this study and may be used to aid in treatment optimization.

Exercise improvement and plasma biomarker changes with intravenous treprostinil therapy for pulmonary arterial hypertension: a placebo-controlled trial.

BACKGROUND: Pulmonary arterial hypertension (PAH) remains a poorly understood and frequently lethal disease with few treatment options. METHODS: We conducted a placebo-controlled trial of intravenous treprostinil, a prostacyclin analog, in treatment-naive PAH patients. During 12 weeks of treatment with treprostinil or placebo, we quantified 6-minute walk distance (6MW), clinical symptoms and 11 cytokines/growth factors. RESULTS: Forty-two of 44 study patients had idiopathic/familial PAH in New York Heart Association (NYHA) Class III. Treprostinil increased 6MW by a placebo-corrected median of 83 meters (p = 0.008; mean increase 93 +/- 42 meters), reduced Borg score by a median 2.0 units (p = 0.02), and improved NYHA class by a median of 1.0 (p = 0.02). There was a trend toward improved survival with treprostinil (p = 0.051). Baseline plasma angiopoietin-2 (Ang-2), vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9) and platelet-derived growth factor (PDGF) were elevated compared with reported normal ranges. Treatment with treprostinil was associated with decreased Ang-2 levels. Improvement in 6MW distance after treatment was associated with reductions in Ang-2 and MMP-9 levels. Most of the cytokines and growth factors studied were not abnormal with disease nor did they change with treatment. CONCLUSIONS: We conclude that treprostinil treatment significantly improved exercise capacity, dyspnea and functional class. Several plasma proteins that might track disease were abnormal at baseline, and changes were associated with improved exercise capacity.

Dose proportionality of treprostinil sodium administered by continuous subcutaneous and intravenous infusion.

This study assessed the relationship between dose and plasma concentration following administration of treprostinil sodium infusion therapy in pulmonary arterial hypertension patients. This was a multicenter, open-label, multiple-cohort, steady-state, pharmacokinetic study in subjects with pulmonary arterial hypertension receiving treprostinil by continuous intravenous or subcutaneous infusion at doses between 10 and 125 ng/kg/min. A blood sample was obtained from each patient at steady state and analyzed via a liquid chromatography/tandem mass spectrometry method. Forty-nine subjects receiving treprostinil were enrolled. Treprostinil doses ranged from 12.1 to 125 ng/kg/min; treprostinil plasma concentrations ranged from 14.9 to 18 248 pg/mL. Linear regression analysis revealed a correlation between treprostinil dose and treprostinil plasma concentration with an R2 value of 0.561. Using a power model to assess dose proportionality, the estimated nonproportionality parameter was 0.641 (95% confidence interval: 0.083-1.199), reflecting consistency with dose proportionality. Subset linear regression analysis, which excluded 2 subjects with anomalous treprostinil plasma concentrations, increased the R2 value to 0.796. Using a power model to assess dose proportionality of this subset, the estimated nonproportionality parameter was 0.941 (95% confidence interval: 0.809-1.073). This study supports previous findings of linearity at lower doses up to 15 ng/kg/min and demonstrates linearity at treprostinil doses up to 125 ng/kg/min.

Pharmacokinetics and steady-state bioequivalence of treprostinil sodium (Remodulin) administered by the intravenous and subcutaneous route to normal volunteers.

Treprostinil sodium is a chemically stable analogue of prostacyclin administered as a chronic, continuous subcutaneous infusion for the treatment of pulmonary arterial hypertension (PAH). There has been significant clinical interest in determining the feasibility of delivering treprostinil by intravenous infusion. Therefore, a bioequivalence and comparative pharmacokinetics study of the two routes of administration was conducted in normal volunteers. A randomized, two-period, crossover study design was employed. Each subject was dosed at 10 ng/kg/min for 72 hours by each route, with the infusions separated by a 4-day wash-out period. In the 51 subjects who received at least 24 hours of treprostinil administered subcutaneously and intravenously, the steady-state ratios of the geometric means (i.v./s.c.) and 90% confidence intervals for AUCss and Cmaxss were 92.9% (89.8-96.1%) and 106% (99.4-113%), respectively. Secondary pharmacokinetic assessments confirmed the comparability of the two routes of administration at steady state, and also demonstrated that the elimination half-life of treprostinil was 4.4 and 4.6 hours following intravenous and subcutaneous administration, respectively. Based on these findings it was concluded that intravenously and subcutaneously administered treprostinil are bioequivalent at steady state.

Pharmacokinetics of treprostinil sodium administered by 28-day chronic continuous subcutaneous infusion.

The objective of this study was to assess the pharmacokinetics and safety of treprostinil sodium administered as a 28-day continuous subcutaneous infusion at escalating infusion rates of 2.5 to 15 ng/kg/min in normal subjects. Fourteen healthy adult volunteers received a 28-day continuous sub-cutaneous infusion of treprostinil at escalating infusion rates of 2.5, 5, 10, and 15 ng/kg/min. Doses were escalated every 7 days with no washouts between escalations. Serial plasma samples were collected predosing, during dosing, and postdosing. Samples were also collected every 3 hours on Day 7 of each dosing period to evaluate diurnal variation over a 24-hour steady-state interval. Plasma treprostinil concentration was measured by a validated liquid chromatography atmospheric pressure ionization tandem mass spectrometry (LC/MS/MS) method with a lower limit of quantitation (LLOQ) of 25 pg/mL. Distinct steady states were achieved for each of the four treprostinil doses. Linear regression analysis of mean steady-state treprostinil concentration versus targeted dose yielded a fitted line with an r(2) of 0.92. Variation in apparent plasma clearance for the four doses was small (i.e., 9.77-10.4 mL/kg/min). Consistent diurnal cycles of two peak and two trough treprostinil concentrations were observed over a 24-hour steady-state interval for each dose with peak levels 20% to 30% higher than trough levels. The terminal half-life of treprostinil was 2.93 hours. Intersubject variability for mean pharmacokinetic parameters was small (coefficients of variation ranging from 13.6%-25.5%). At clinically relevant doses, the pharmacokinetics of treprostinil were linear and dose independent with modest, consistent diurnal cycles consisting of two daily peaks and two daily troughs observed for all four doses. In addition, the elimination half-life was about 3 hours.

Multiple-center, randomized, placebo-controlled, double-blind study of the nitric oxide synthase inhibitor 546C88: effect on survival in patients with septic shock.

OBJECTIVE: To assess the safety and efficacy of the nitric oxide synthase inhibitor 546C88 in patients with septic shock. The predefined primary efficacy objective was survival at day 28. DESIGN: Multiple-center, randomized, two-stage, double-blind, placebo-controlled, safety and efficacy study. SETTING: A total of 124 intensive care units in Europe, North America, South America, South Africa, and Australasia. PATIENTS: A total of 797 patients with septic shock diagnosed for <24 hrs. INTERVENTIONS: Patients with septic shock were allocated to receive 546C88 or placebo (5% dextrose) for up to 7 days (stage 1) or 14 days (stage 2) in addition to conventional therapy. Study drug was initiated at 0.05 mL.kg(-1).hr(-1) (2.5 mg.kg(-1).hr(-1) 546C88) and titrated up to a maximum rate of 0.4 mL.kg(-1).hr(-1) to maintain mean arterial pressure between 70 and 90 mm Hg while attempting to withdraw concurrent vasopressors. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variables, organ function data, microbiological data, concomitant therapy, and adverse event data were recorded at baseline, throughout treatment, and at follow-up. The primary end point was day-28 survival. The trial was stopped early after review by the independent data safety monitoring board. Day-28 mortality was 59% (259/439) in the 546C88 group and 49% (174/358) in the placebo group (p <.001). The overall incidence of adverse events was similar in both groups, although a higher proportion of the events was considered possibly attributable to study drug in the 546C88 group. Most of the events accounting for the disparity between the groups were associated with the cardiovascular system (e.g., decreased cardiac output, pulmonary hypertension, systemic arterial hypertension, heart failure). The causes of death in the study were consistent with those expected in patients with septic shock, although there was a higher proportion of cardiovascular deaths and a lower incidence of deaths caused by multiple organ failure in the 546C88 group. CONCLUSIONS: In this study, the nonselective nitric oxide synthase inhibitor 546C88 increased mortality in patients with septic shock.

Beraprost therapy for pulmonary arterial hypertension.

OBJECTIVES: The purpose of this study was to assess the safety and efficacy of the oral prostacyclin analogue beraprost sodium during a 12-month double-blind, randomized, placebo-controlled trial in patients with pulmonary arterial hypertension (PAH). BACKGROUND: Pulmonary arterial hypertension is a progressive disease that ultimately causes right heart failure and death. Despite the risks from its delivery system, continuous intravenous epoprostenol remains the most efficacious treatment currently available. METHODS: A total of 116 patients with World Health Organization (WHO) functional class II or III primary pulmonary hypertension or PAH related to either collagen vascular diseases or congenital systemic to pulmonary shunts were enrolled. Patients were randomized to receive the maximal tolerated dose of beraprost sodium (median dose 120 microg four times a day) or placebo for 12 months. The primary end point was disease progression; i.e., death, transplantation, epoprostenol rescue, or >25% decrease in peak oxygen consumption (VO(2)). Secondary end points included exercise capacity assessed by 6-min walk test and peak VO(2), Borg dyspnea score, hemodynamics, symptoms of PAH, and quality of life. RESULTS: Patients treated with beraprost exhibited less evidence of disease progression at six months (p = 0.002), but this effect was not evident at either shorter or longer follow-up intervals. Similarly, beraprost-treated patients had improved 6-min walk distance at 3 months by 22 m from baseline and at 6 months by 31 m (p = 0.010 and 0.016, respectively) compared with placebo, but not at either 9 or 12 months. Drug-related adverse events were common and were related to the disease and/or expected prostacyclin adverse events. CONCLUSIONS: These data suggest that beneficial effects may occur during early phases of treatment with beraprost in WHO functional class II or III patients but that this effect attenuates with time.

Efficacy and safety of treprostinil: an epoprostenol analog for primary pulmonary hypertension.

Intravenous epoprostenol is currently FDA approved for management of primary pulmonary hypertension, but it requires intravenous infusion and is associated with adverse effects. The objective of this study was to evaluate the effects of an epoprostenol analog, treprostinil, for management of pulmonary hypertension. Ten tertiary care academic institutions with pulmonary hypertension programs participated in these pilot trials. In the first trial, intravenous epoprostenol and intravenous treprostinil were compared. In the second trial, intravenous treprostinil and subcutaneous treprostinil were compared. In the third trial, subcutaneous treprostinil was compared with placebo infusion during an 8-week period. Intravenous epoprostenol and intravenous treprostinil resulted in a similar reduction in pulmonary vascular resistance acutely (22% and 20%, respectively). Intravenous treprostinil and subcutaneous treprostinil also demonstrated comparable short-term decrease in pulmonary vascular resistance (23% and 28%, respectively). The placebo-controlled 8-week trial demonstrated a mean improvement of 37 +/- 17 m as measured by the 6-minute walk distance in patients receiving treprostinil compared with a 6 +/- 28 m reduction in those receiving placebo. There were trends toward an improvement in cardiac index and pulmonary vascular resistance index in the treprostinil group. Subcutaneous treprostinil has favorable hemodynamic effects when given acutely and in the short term. Treprostinil can be given safely to an ambulatory patient with a novel subcutaneous delivery pump system.