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Background: In pulmonary arterial hypertension (PAH), adding oral sildenafil to intravenous epoprostenol improved 6-minute walk distance (6MWD) and hemodynamics and delayed time to clinical worsening in a 16-week randomized, placebo-controlled trial (Pulmonary Arterial Hypertension Combination Study of Epoprostenol and Sildenafil [PACES-1])., Methods: Patients completing PACES-1 could receive sildenafil (titrated to 80 mg, three times daily, as tolerated) in an open-label extension study (PACES-2) for ≥ 3 years; additional therapy was added according to investigator judgment. Survival and changes from PACES-1 baseline in World Health Organization Functional Class and 6MWD were captured., Results: In an open-label setting, 6MWD, an effort-dependent outcome measure, was known to have improved or to have been maintained in 59%, 44%, and 33% of patients at 1, 2, and 3 years, respectively; functional class was known to have improved or to have been maintained in 73%, 59%, and 46%. At 3 years, 66% of patients were known to be alive, 24% were known to have died, and 10% were lost to follow-up. Patients with PACES-1 baseline 6MWD < 325 meters without 6MWD improvement during the first 20 weeks of sildenafil treatment subsequently had poorer survival., Conclusions: Although reliable assessments of safety and efficacy require a long-term randomized trial, the addition of sildenafil to background intravenous epoprostenol therapy appeared generally to be well tolerated in PAH patients., (Copyright © 2014 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: The long-term safety and tolerability of sildenafil treatment of pulmonary arterial hypertension (PAH) were assessed., Methods: Two hundred fifty-nine of 277 randomized and treated patients completed a 12-week, double-blind, placebo-controlled trial (SUPER-1 [Sildenafil Use in Pulmonary Arterial Hypertension]) of oral sildenafil in treatment-naive patients with PAH (96% functional class II/III) and entered an open-label uncontrolled extension study (SUPER-2) that continued until the last patient completed 3 years of sildenafil treatment. Patients titrated to sildenafil 80 mg tid; one dose reduction for tolerability was allowed during the titration phase., Results: The median duration of sildenafil treatment across SUPER-1 and SUPER-2 was 1,242 days (range, 1-1,523 days); 170 patients (61%) completed both studies, and 89 patients discontinued from SUPER-2. After 3 years, 87% of 183 patients on treatment were receiving sildenafil 80 mg tid. Of patients remaining under follow-up, 3%, 10%, and 18% were receiving a second approved PAH therapy at 1, 2, and 3 years, respectively. At 3 years post-SUPER-1 baseline, 127 patients had an increased 6-min walk distance (6MWD); 81 improved and 86 maintained functional class. Most adverse events were of mild or moderate severity. At 3 years, 53 patients had died (censored, n = 37). Three-year estimated survival rate was 79%; if all censored patients were assumed to have died, 3-year survival rate was 68%. No deaths were considered to be treatment related., Conclusions: Long-term treatment of PAH initiated as sildenafil monotherapy was generally well tolerated. After 3 years, the majority of patients (60%) who entered the SUPER-1 trial improved or maintained their functional status, and 46% maintained or improved 6MWD.

In adults with sickle cell disease (SCD), an increased tricuspid regurgitation velocity (TRV) by Doppler echocardiography is associated with increased morbidity and mortality. Although sildenafil has been shown to improve exercise capacity in patients with pulmonary arterial hypertension, it has not been evaluated in SCD. We therefore sought to determine whether sildenafil could improve exercise capacity in SCD patients with increased TRV and a low exercise capacity. A TRV ≥ 2.7 m/s and a 6-minute walk distance (6MWD) between 150 and 500 m were required for enrollment in this 16-week, double-blind, placebo-controlled sildenafil trial. After 74 of the screened subjects were randomized, the study was stopped early due to a higher percentage of subjects experiencing serious adverse events in the sildenafil arm (45% of sildenafil, 22% of placebo, P = .022). Subject hospitalization for pain was the predominant cause for this difference: 35% with sildenafil compared with 14% with placebo (P = .029). There was no evidence of a treatment effect on 6MWD (placebo-corrected effect -9 m; 95% confidence interval [95% CI] -56-38; P = .703), TRV (P = .503), or N-terminal pro-brain natriuretic peptide (P = .410). Sildenafil appeared to increase hospitalization rates for pain in patients with SCD. This study is registered at www.clinicaltrials.gov as NCT00492531.

Background: Oral sildenafil and intravenous epoprostenol have independently been shown to be effective in patients with pulmonary arterial hypertension., Objective: To investigate the effect of adding oral sildenafil to long-term intravenous epoprostenol in patients with pulmonary arterial hypertension., Design: A 16-week, double-blind, placebo-controlled, parallel-group study., Setting: Multinational study at 41 centers in 11 countries from 3 July 2003 to 27 January 2006., Patients: 267 patients with pulmonary arterial hypertension (idiopathic, associated anorexigen use or connective tissue disease, or corrected congenital heart disease) who were receiving long-term intravenous epoprostenol therapy., Intervention: Patients were randomly assigned to receive placebo or sildenafil, 20 mg three times daily, titrated to 40 mg and 80 mg three times daily, as tolerated, at 4-week intervals. Of 265 patients who received treatment, 256 (97%) patients (123 in the placebo group and 133 in the sildenafil group) completed the study., Measurements: Change from baseline in exercise capacity measured by 6-minute walk distance (primary end point) and hemodynamic measurements, time to clinical worsening, and Borg dyspnea score (secondary end points)., Results: A placebo-adjusted increase of 28.8 meters (95% CI, 13.9 to 43.8 meters) in the 6-minute walk distance occurred in patients in the sildenafil group; these improvements were most prominent among patients with baseline distances of 325 meters or more. Relative to epoprostenol monotherapy, addition of sildenafil resulted in a greater change in mean pulmonary arterial pressure by -3.8 mm Hg (CI, -5.6 to -2.1 mm Hg); cardiac output by 0.9 L/min (CI, 0.5 to 1.2 L/min); and longer time to clinical worsening, with a smaller proportion of patients experiencing a worsening event in the sildenafil group (0.062) than in the placebo group (0.195) by week 16 (P = 0.002). Health-related quality of life also improved in patients who received combined therapy compared with those who received epoprostenol monotherapy. There was no effect on the Borg dyspnea score. Of the side effects generally associated with sildenafil treatment, the most commonly reported in the placebo and sildenafil groups, respectively, were headache (34% and 57%; difference, 23 percentage points [CI, 12 to 35 percentage points]), dyspepsia (2% and 16%; difference, 13 percentage points [CI, 7 to 20 percentage points]), pain in extremity (18% and 25%; difference, 8 percentage points [CI, -2 to 18 percentage points]), and nausea (18% and 25%; difference, 8 percentage points [CI, -2 to 18 percentage points])., Limitations: The study excluded patients with pulmonary arterial hypertension associated with other causes. There was an imbalance in missing data between groups, with 8 placebo recipients having no postbaseline walk assessment compared with 1 sildenafil recipient. These patients were excluded from the analysis., Conclusion: In some patients with pulmonary arterial hypertension, the addition of sildenafil to long-term intravenous epoprostenol therapy improves exercise capacity, hemodynamic measurements, time to clinical worsening, and quality of life, but not Borg dyspnea score. Increased rates of headache and dyspepsia occurred with the addition of sildenafil.

Objective: Pulmonary arterial hypertension associated with connective tissue disease (PAH-CTD) is difficult to manage, and has a poor prognosis. The phosphodiesterase-5 inhibitor sildenafil citrate enhances vasodilatation, has antiproliferative effects, and is effective in the treatment of PAH. We examined the efficacy and safety of oral sildenafil in patients with PAH-CTD., Methods: In a 12-week, double-blind study (SUPER-1), 278 patients with PAH were randomized to oral placebo, sildenafil 20 mg, sildenafil 40 mg, or sildenafil 80 mg 3 times daily (tid). In a post-hoc subgroup analysis of 84 patients with PAH-CTD, exercise capacity, hemodynamic measures, World Health Organization functional class, and tolerability were assessed., Results: Forty-five percent of the patients had scleroderma, 23% had systemic lupus erythematosus, and the rest (32%) were categorized as other. Patients were predominantly functional class II (38%) or III (61%) at baseline. Sildenafil-treated patients exhibited mean increases in 6-minute walk distance at Week 12 of 42 m (95% CI 20, 64) for 20 mg, 36 m (95% CI 14, 58) for 40 mg, and 15 m (95% CI -24, 54) for 80 mg, while placebo-treated patients exhibited a mean decrease of 13 m (95% CI -36, 10). Improvement of at least 1 functional class occurred in 29%-42% of sildenafil-treated patients, compared to 5% for placebo. Significant improvements in mean pulmonary arterial pressure and pulmonary vascular resistance were observed with sildenafil 20 mg, and sildenafil was generally well tolerated., Conclusion: In patients with PAH-CTD, sildenafil improves exercise capacity, hemodynamic measures (at the 20 mg dose), and functional class after 12 weeks of treatment.