B.K.S. Sastry

A Randomized, Double-Blind, Placebo-Controlled, Dose-Ranging Study of Oral Sildenafil Citrate in Treatment-Naive Children With Pulmonary Arterial Hypertension

Background— Safe, effective therapy is needed for pediatric pulmonary arterial hypertension. Methods and Results— Children (n=235; weight ≥8 kg) were randomized to low-, medium-, or high-dose sildenafil or placebo orally 3 times daily for 16 weeks in the Sildenafil in Treatment-Naive Children, Aged 1–17 Years, With Pulmonary Arterial Hypertension (STARTS-1) study. The primary comparison was percent change from baseline in peak oxygen consumption (PV[Combining Dot Above]O2) for the 3 sildenafil doses combined versus placebo. Exercise testing was performed in 115 children able to exercise reliably; the study was powered for this population. Secondary end points (assessed in all patients) included hemodynamics and functional class. The estimated mean±SE percent change in PV[Combining Dot Above]O2 for the 3 doses combined versus placebo was 7.7±4.0% (95% confidence interval, −0.2% to 15.6%; P=0.056). PV[Combining Dot Above]O2, functional class, and hemodynamics improved with medium and high doses versus placebo; low-dose sildenafil was ineffective. Most adverse events were mild to moderate in severity. STARTS-1 completers could enter the STARTS-2 extension study; patients who received sildenafil in STARTS-1 continued the same dose, whereas placebo-treated patients were randomized to low-, medium-, or high-dose sildenafil. In STARTS-2 (ongoing), increased mortality was observed with higher doses. Conclusions— Sixteen-week sildenafil monotherapy is well tolerated in pediatric pulmonary arterial hypertension. Percent change in PV[Combining Dot Above]O2 for the 3 sildenafil doses combined was only marginally significant; however, PV[Combining Dot Above]O2, functional class, and hemodynamic improvements with medium and high doses suggest efficacy with these doses. Combined with STARTS-2 data, the overall profile favors the medium dose. Further investigation is warranted to determine optimal dosing based on age and weight. Clinical Trial Registration— http://www.clinicaltrials.gov. Unique identifier: NCT00159913.

Effect of Macitentan on Hospitalizations: Results From the SERAPHIN Trial

OBJECTIVES This study sought to evaluate the effect of macitentan on hospitalization of patients with symptomatic pulmonary arterial hypertension (PAH). BACKGROUND PAH is a progressive, life-threatening disease often requiring hospitalization. METHODS In the multicenter, double-blind, randomized, event-driven, phase III SERAPHIN (Study with an Endothelin Receptor Antagonist in Pulmonary arterial Hypertension to Improve cliNical outcome) trial, patients with symptomatic PAH were randomized (1:1:1) to receive placebo or 3 mg or 10 mg of macitentan. Effects of macitentan on the risk, rate, and number of hospital days for all-cause and PAH-related hospitalizations were compared with those for placebo. Risk and causes of hospitalizations unrelated to PAH were investigated. RESULTS Of 742 randomized patients, 250 received placebo, 250 received 3 mg of macitentan, and 242 received 10 mg of macitentan; the overall median duration of treatment was 115 weeks. Risk of all-cause hospitalization was reduced by 18.9% (p = 0.1208) and 32.3% (p = 0.0051) in the macitentan 3-mg and 10-mg arm, respectively. Rates of all-cause hospitalizations and numbers of hospital days were reduced by 20.5% (p = 0.0378) and 30.6% (p = 0.0278), respectively, with 3 mg of macitentan and by 33.1% (p = 0.0005) and 31.0% (p = 0.0336), respectively, with 10 mg of macitentan. Risk of PAH-related hospitalizations were reduced by 42.7% (p = 0.0015) and 51.6% (p < 0.0001) in the macitentan 3-mg and 10-mg arms, respectively. Rate of PAH-related hospitalizations and numbers of hospital days were reduced by 44.5% (p = 0.0004) and 53.3% (p = 0.0001), respectively, with 3 mg of macitentan, and reduced by 49.8% (p < 0.0001) and 52.3% (p = 0.0003), respectively, with 10 mg of macitentan. Risk of non-PAH-related hospitalization was similar between treatment arms. CONCLUSIONS Macitentan 10 mg significantly reduced the risk and rate of all-cause hospitalization, which was driven by reductions in the risk and rate of PAH-related hospitalization. (Study of Macitentan [ACT-064992] on Morbidity and Mortality in Patients With Symptomatic Pulmonary Arterial Hypertension; NCT00660179).

Incident and prevalent cohorts with pulmonary arterial hypertension: insight from SERAPHIN

In SERAPHIN, a long-term, randomised, controlled trial (NCT00660179) in pulmonary arterial hypertension (PAH), macitentan significantly reduced the risk of morbidity/mortality and PAH-related death/hospitalisation. We evaluated disease progression and the effect of macitentan in treatment-naïve incident and prevalent cohorts. Patients allocated to placebo, or macitentan 3 mg or 10 mg were classified by time from diagnosis to enrolment as incident (≤6 months; n=110) or prevalent (>6 months; n=157). The risk of morbidity/mortality and PAH-related death/hospitalisation was determined using Cox regression. The risk of morbidity/mortality (Kaplan–Meier estimates at month 12: 54.4% versus 26.7%; p=0.006) and PAH-related death/hospitalisation (Kaplan–Meier estimates at month 12: 47.3% versus 19.9%; p=0.006) were significantly higher for incident versus prevalent patients receiving placebo, respectively. There was no significant difference in the risk of all-cause death between incident and prevalent cohorts (p=0.587). Macitentan 10 mg significantly reduced the risk of morbidity/mortality and PAH-related death/hospitalisation versus placebo in incident and prevalent cohorts. Incident patients had a higher risk for PAH progression compared with prevalent patients but not a higher risk of death. Macitentan delayed disease progression in both incident and prevalent PAH patients. In the SERAPHIN trial, incident PAH patients had a higher risk of disease progression than prevalent patients http://ow.ly/RvCei

SERAPHIN haemodynamic substudy: the effect of the dual endothelin receptor antagonist macitentan on haemodynamic parameters and NT-proBNP levels and their association with disease progression in patients with pulmonary arterial hypertension

Aims The effect of macitentan on haemodynamic parameters and NT-proBNP levels was evaluated in pulmonary arterial hypertension (PAH) patients in the SERAPHIN study. Association between these parameters and disease progression, assessed by the primary endpoint (time to first morbidity/mortality event), was explored. Methods and results Of the 742 randomized patients, 187 with right heart catheterization at baseline and month 6 participated in a haemodynamic sub-study. Prespecified endpoints included change from baseline to month 6 in cardiac index (CI), right atrial pressure (RAP), mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), mixed-venous oxygen saturation, and NT-proBNP. Exploratory analyses examined associations between CI, RAP, and NT-proBNP and disease progression using the Kaplan-Meier method and Cox regression models. Macitentan improved CI, RAP, mPAP, PVR and NT-proBNP vs. placebo at month 6. Absolute levels of CI, RAP and NT-proBNP at baseline and month 6, but not their changes, were associated with morbidity/mortality events. Patients with CI > 2.5 L/min/m2, RAP < 8 mmHg, or NT-proBNP < 750 fmol/ml at month 6 had a lower risk of morbidity/mortality than those not meeting these thresholds (HR 0.49, 95% CL 0.28–0.86; HR 0.72, 95% CL 0.42–1.22; and HR 0.22, 95% CL 0.15–0.33, respectively). Conclusions For all treatment groups, baseline and month 6 values of CI, RAP, and NT-proBNP, but not their changes, were associated with morbidity/mortality events, confirming their relevance in predicting disease progression in patients with PAH. By improving those parameters, macitentan increased the likelihood of reaching threshold values associated with lower risk of morbidity/mortality.

Association between six-minute walk distance and long-term outcomes in patients with pulmonary arterial hypertension: Data from the randomized SERAPHIN trial

Background Patients with pulmonary arterial hypertension who achieve a six-minute walk distance of 380–440 m may have improved prognosis. Using the randomized controlled trial of macitentan in pulmonary arterial hypertension (SERAPHIN), the association between six-minute walk distance and long-term outcomes was explored. Methods Patients with six-minute walk distance data at Month 6 were dichotomized as above or below the median six-minute walk distance (400 m) and assessed for future risk of pulmonary arterial hypertension-related death or hospitalization and all-cause death. Additionally, six-minute walk distance values at baseline, Month 6 and the change from baseline to Month 6 were categorized by quartiles. All associations were analyzed by the Kaplan–Meier method using a log-rank test and Cox regression models. Results Patients with a six-minute walk distance >400 m vs. ≤400 m at Month 6 have a reduced risk of pulmonary arterial hypertension-related death or hospitalization (hazard ratio 0.48; 95% confidence interval 0.33–0.69). The risk was also lower for patients with higher quartiles of six-minute walk distance at baseline or Month 6 (baseline: hazard ratio [Q4 (>430 m) vs. Q1 (≤300 m)] 0.23; 95% confidence interval 0.15–0.36; Month 6: hazard ratio [Q4 (>455 m) vs. Q1 (≤348 m)] 0.33; 95% confidence interval 0.19–0.55). In contrast, six-minute walk distance changes at Month 6 were not associated with the risk of pulmonary arterial hypertension-related death or hospitalization (p = 0.477). These findings were consistent when adjusted for known confounders. Similar results were observed for the risk of all-cause death up to end of study. Conclusions Patients with pulmonary arterial hypertension walking >400 m had better long-term prognosis. Although changes in six-minute walk distance were not associated with long-term outcomes, assessing absolute six-minute walk distance values remains important in the clinical management of patients with pulmonary arterial hypertension.