It is hypothesised that ambrisentan may provide benefit to subjects with inoperable chronic thromboembolic pulmonary hypertension (CTEPH), where currently no proven or licensed treatment options exist. This Phase III, randomized, double-blind placebo controlled parallel group, 16 week study will compare the safety and efficacy of ambrisentan 5 milligrams (mg) versus placebo in subjects with inoperable CTEPH. The study will enrol 160 subjects, to assure at least 72 evaluable subjects per treatment arm, based on 10% drop-out rate.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
33
White, film-coated, immediate-release tablets, containing 5 mg ambrisentan for single dose oral.
White, film-coated, ambrisentan-matching placebo tablet for single oral dose
Change From Baseline in Six Minutes Walking Distance (6MWD) at Week 16
The 6-minute walk test was conducted according to the American Thoracic Society guidelines in accordance with local standard operating procedures. 6MWD was measured by a 6-minute walk test. This test measures the distance that a participant can walk in a period of 6 minutes. Change from baseline was calculated at Weeks 4, 8, 12 and 16. Change from Baseline was calculated as value at the specified visit minus the Baseline value. Data at Baseline is based on average of two consecutive test results during Screening/Baseline period that differ by \<10%. If only one measurement was available, that measurement was used. In any cases where the protocol-defined criteria for Baseline 6MWD was not met, the Baseline value was based on the last two consecutive measurements for a participant.
Time frame: Baseline (Week 0); Weeks 4, 8, 12 and 16/Early Withdrawal
Change From Baseline in Pulmonary Vascular Resistance (PVR) at Week 16
PVR is a measure of cardiopulmonary haemodynamics. Change from Baseline was calculated as value at specified visit minus Baseline value. Baseline is the last value recorded on or prior to start of study treatment.
Time frame: Baseline (Week 0) and Week 16
Change From Baseline in WHO Functional Class (FC) at Weeks 4, 8, 12 and 16/Early Withdrawal
The WHO FC indicates the severity of PAH and is an adaptation of the New York Heart Association classification. It was assessed by the investigator. There are four grades for WHO FC based on severity of symptoms (Class I = none, Class IV = most severe). This functional classification system links symptoms with activity limitations, and allows clinicians to quickly predict disease progression and prognosis, as well as the need for specific treatment regimens, irrespective of the underlying etiology of PAH. Baseline is the last value recorded on or prior to start of study treatment. Change from Baseline was calculated as the value at specified visit minus the Baseline value. For analyse purposes, the WHO FC Class categories of I-IV were mapped to a numeric scale of 1-4.
Time frame: Baseline (Week 0); Weeks 4, 8, 12 and 16/Early Withdrawal
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GSK Investigational Site
Boston, Massachusetts, United States
GSK Investigational Site
Dallas, Texas, United States
GSK Investigational Site
Corrientes, Corrientes Province, Argentina
GSK Investigational Site
Rosario, Santa Fe Province, Argentina
GSK Investigational Site
Santa Fe, Santa Fe Province, Argentina
GSK Investigational Site
Buenos Aires, Argentina
GSK Investigational Site
Graz, Austria
GSK Investigational Site
Innsbruck, Austria
GSK Investigational Site
Vienna, Austria
GSK Investigational Site
Edmonton, Alberta, Canada
...and 41 more locations
Change From Baseline in Borg CR10 Scale (BCR10S) Immediately Following Exercise at Weeks 4, 8, 12 and 16/Early Withdrawal
The BCR10S score was collected immediately following completion of the 6-minute walk test. Baseline data was calculated as the average of the two BCR10S values obtained following the two 6MWD tests used in determining the Baseline 6MWD. If only one measurement was available, that measurement has been used. BCR10S scores ranges from 0 to 10 (0=nothing at all, 10=extremely strong). If participant's perception or feeling was stronger than "10", i.e "extremely strong", "Maximal" - a larger number could be used, e.g. 12 or still higher i.e "Absolute maximum"). Change from Baseline was calculated as the value at specified visit minus the Baseline value.
Time frame: Baseline (Week 0); Weeks 4, 8, 12 and 16/Early Withdrawal
Number of Participants With Clinical Worsening of Chronic Thromboembolic Pulmonary Hypertension (CTEPH)
Clinical worsening of CTEPH is defined by the time from randomization to the first occurrence of death, lung transplantation, hospitalization for CTEPH, atrial septostomy, addition of parenteral prostanoids, or study withdrawal due to two or more early escape criteria included: a decrease from Baseline of at least 20 percent in the distance walked during the six-minute walk test; an increase of one or more WHO functional class; worsening right ventricular failure (e.g., as indicated by increased jugular venous pressure; new/worsening hepatomegaly, ascites, or peripheral edema; worsening echocardiographic parameters such as tricuspid annulus plane systolic excursion (TAPSE) and Tissue Doppler Imaging of the tricuspid annulus); rapidly progressing cardiogenic, hepatic, or renal failure; refractory systolic hypotension (systolic blood pressure less than 85 millimeter of mercury \[mmHg\]).
Time frame: From randomization to Week 16/Follow up visit (21 weeks)
Change From Baseline in Mean Right Atrial Pressure (mRAP) and Mean Pulmonary Artery Pressure (mPAP) at Week 16
mPAP and mRAP are measures of cardiopulmonary hemodynamics. Baseline is the last value recorded on or prior to start of study treatment. Change from Baseline was calculated as the value at specified visit minus the Baseline value.
Time frame: Baseline (Week 0) and Week 16
Change From Baseline in Cardiac Index at Week 16
Cardiac index is measure of cardiopulmonary hemodynamics. Baseline is the last value recorded on or prior to start of study treatment. Change from Baseline was calculated as the value at specified visit minus the Baseline value.
Time frame: Baseline (Week 0) and Week 16
Percent Change From Baseline in Plasma N-terminal Pro-B-type Natriuretic Peptide (NT-proBNP)
The ratio to baseline \[BL\] in NT-proBNP was calculated as the ratio of the value at the specified time-point to the BL value and was expressed as a percent change from BL. For each treatment group, the mean change from BL at the specified time-point was determined on the log scale. This mean was then back transformed to give a geometric mean (GM) of the ratio of the value at the specified time-point to BL on the original scale. The GM was expressed as a percentage (100\*\[GM - 1\]). Standard Deviation(SD) is the SD of the mean change from baseline values on the log scale.
Time frame: Baseline (Week 0); Weeks 4, 8, 12 and 16/Early Withdrawal
Change From Baseline in Quality of Life as Measured by Short Form 36 Health Survey (SF-36)
The SF-36 v2 is a self-administered, health-related quality of life (QoL) metric. It is a 36-item questionnaire designed to measure 8 domains of functional health status and well-being: physical functioning, role-physical, bodily pain, general health perceptions, vitality, social functioning, role-emotional, and mental health as well as 2 summary measures (Physical Health and Mental Health). Each domain is scored from 0 (poorer health) to 100 (better health). Change from Baseline was calculated as the post-Baseline score minus the Baseline score. The SF-36 data were collected, but after the study was terminated, not all endpoints listed in the protocol were analyzed, including the SF-36. This decision was documented in the reporting and analysis plan prior to database lock.
Time frame: Baseline and up to Week 16/Early Withdrawal
Number of Participants With Any Adverse Events (AEs) and Serious Adverse Events (SAEs)
AE is defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a medicinal product. For marketed medicinal products, this also includes failure to produce expected benefits (i.e., lack of efficacy), abuse or misuse. A SAE is defined as any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity or is a congenital anomaly/birth defect or important medical events that may not be immediately life-threatening or result in death or hospitalization but may jeopardize the participant or may require medical or surgical intervention to prevent one of the other outcomes listed in the above definition.
Time frame: From the start of study treatment and until follow up (Week 16/Follow up)
Change From Baseline in Haemoglobin Levels at Weeks 4, 8, 12, and 16/Early Withdrawal
Haemoglobin levels were assessed at Screening, Baseline, Weeks 4, 8, 12, and 16/Early Withdrawal. Baseline is the last value recorded on or prior to start of study treatment. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.
Time frame: Baseline (Week 0); Weeks 4, 8, 12, and 16/Early Withdrawal
Change From Baseline in Haematocrit Levels at Weeks 4, 8, 12, and 16/Early Withdrawal
Haematocrit levels were assessed at Screening, Baseline, Weeks 4, 8, 12, and 16/Early Withdrawal. Baseline is the last value recorded on or prior to start of study treatment. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.
Time frame: Baseline (Week 0); Weeks 4, 8, 12, and 16/Early Withdrawal
Number of Participants With Significant Liver Events at Weeks 4, 8, 12, and 16/Early Withdrawal
A significant liver chemistry result is defined as any result which met the stopping criteria defined in the study protocol. Liver events were assessed at Screening, Baseline, Weeks 4, 8, 12, and 16/Early Withdrawal. Number of participants who reported a significant liver chemistry result are presented.
Time frame: Weeks 4, 8, 12, and 16/Early Withdrawal
Change From Baseline in Supine Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) Assessed at Weeks 4, 8, 12, and 16/Early Withdrawal
Vital sign measurements including supine systolic and diastolic blood pressure at Weeks 4, 8, 12, and 16/Early Withdrawal weeks. Supine blood pressure measurement was taken in a supine position having rested in this position for at least 10 minutes before each reading. Baseline is the last value recorded on or prior to start of study treatment. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.
Time frame: Baseline (Week 0); Weeks 4, 8, 12, and 16/Early Withdrawal
Change From Baseline in Heart Rate Assessed at Weeks 4, 8, 12, and 16/Early Withdrawal
Vital sign measurements including heart rate at Weeks 4, 8, 12, and 16/Early Withdrawal weeks. Baseline is the last value recorded on or prior to start of study treatment. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.
Time frame: Baseline (Week 0); Weeks 4, 8, 12, and 16/Early Withdrawal
Number of Participants With Clinical Chemistry Parameters of Potential Clinical Concern Any Time Post Baseline
Clinical chemistry parameters including alanine amino transferase (ALT), aspartate amino transferase (AST), creatinine, gamma glutamyl transferase (GGT) and total bilirubin (TB) assessed any time post Baseline. ALT: lower concern value and high concern value was considered as none and \>=3xupper limit of normal (ULN) respectively. AST: lower concern value and high concern value was considered as none or \>=3xULN respectively. creatinine: lower concern value and high concern value was considered as none and \>=176.8 micromoles per liter (umol/L) respectively. GGT: lower concern value and high concern value was considered as none and \>=3xULN respectively. For TB: lower concern value was none and high concern value was \>=2xULN. Participants with both normal and low values were counted once under their worst case (Low). Participants with both normal and high values were counted once under their worst case (High). Participants with both high and low values are counted under both categories.
Time frame: Baseline (Week 0), Weeks 4, 8, 12 and 16/early withdrawal,
Number of Participants With Hematology Parameters of Potential Clinical Concern Any Time Post Baseline
Hematology parameters including hemoglobin, international normalized ratio (INR), and platelet count assessed any time post Baseline. Baseline is the last value recorded on or prior to start of study treatment. For hemoglobin: lower concern value and high concern value was considered as \<100 gram per liter (G/L) and none respectively. For INR: lower concern value and high concern value was considered as none or \>5 prothrombin time respectively. For platelet count: lower concern value and high concern value was considered as \<50 giga cells per liter (GI/L) and \>500 GI/L respectively. Participants with both normal and low values were counted once under their worst case (Low). Participants with both normal and high values were counted once under their worst case (High). Participants with both high and low values are counted under both categories.
Time frame: Baseline (Week 0), Weeks 4, 8, 12 and 16/early withdrawal
Number of Participants With Testicular Function (Males Only) of Potential Clinical Concern Any Time Post Baseline
For male participants testicular function (total testosterone, sex hormone binding globulin \[SHBG-calculated free testosterone), follicle stimulating hormone (FSH), luteinizing hormone (LH), and inhibin B were assessed at Weeks 4 and 16/early withdrawal. The testicular function data were collected, but after the study was terminated, not all endpoints listed in the protocol were analyzed, including Testicular Function. This decision was documented in the reporting and analysis plan prior to database lock.
Time frame: Baseline, Weeks 4 and 16/early withdrawal