Trial Outcomes & Findings for A Study of First-Line Ambrisentan and Tadalafil Combination Therapy in Subjects With Pulmonary Arterial Hypertension (PAH) (NCT NCT01178073)

Last Updated: 2017-09-13

Results Overview

Time to the first adjudicated CF event (death, hospitalization for worsening pulmonary arterial hypertension \[PAH\], disease progression, or unsatisfactory long-term clinical response) after initiating either first-line combination therapy with AMB and TAD or first-line monotherapy with either drug (AMB or TAD) in par. with PAH was assessed. If data was not available for some par. following a loss to follow-up, their event times were treated as censored at their last assessment time for the statistical analyses. FAV occurred approximately 4 weeks after the predicted 105th adjudicated first CF event was reached. Par. who had an FAV, and who had no adjudicated events or whose first adjudicated event occurred after their FAV, were censored at their individual FAV. Modified Intent-to-Treat (mITT) Population: all randomized par. who met the PAH diagnosis and inclusion/exclusion criteria defined in protocol amendment 2 and who also received at least one dose of investigational product (IP).

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

610 participants

Primary outcome timeframe

From Baseline up to the Final Assessment Visit (FAV) (average of 609 days)

Results posted on

2017-09-13

Participant Flow

500 participants (par.) in the ITT Population were also included in the modified ITT Population (those who also met the modified inclusion/exclusion criteria defined in the protocol amendment 2). Disposition results below have been presented for the ITT Population.

A total of 610 par. were randomized; however, only 605 were included in the Intent-to-Treat (ITT) Population (randomized par. who received at least one dose of IP). All par. received a minimum of 24 weeks of therapy unless they died or withdrew.

Participant milestones

Participant milestones
Measure	Combination Therapy: Ambrisentan + Tadalafil Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.
Overall Study STARTED	302	152	151
Overall Study COMPLETED	240	108	105
Overall Study NOT COMPLETED	62	44	46

Reasons for withdrawal

Reasons for withdrawal
Measure	Combination Therapy: Ambrisentan + Tadalafil Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.
Overall Study Adverse Event	34	27	24
Overall Study Protocol Violation	1	1	1
Overall Study Lost to Follow-up	2	0	3
Overall Study Physician Decision	14	10	10
Overall Study Withdrawal by Subject	10	6	8
Overall Study Missing Completion Status	1	0	0

Baseline Characteristics

A Study of First-Line Ambrisentan and Tadalafil Combination Therapy in Subjects With Pulmonary Arterial Hypertension (PAH)

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Combination Therapy: Ambrisentan + Tadalafil n=302 Participants Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy n=152 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy n=151 Participants Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.	Total n=605 Participants Total of all reporting groups
Age, Continuous	55.9 Years STANDARD_DEVIATION 13.86 • n=5 Participants	55.2 Years STANDARD_DEVIATION 14.41 • n=7 Participants	55.9 Years STANDARD_DEVIATION 14.75 • n=5 Participants	55.7 Years STANDARD_DEVIATION 14.21 • n=4 Participants
Sex: Female, Male Female	223 Participants n=5 Participants	117 Participants n=7 Participants	121 Participants n=5 Participants	461 Participants n=4 Participants
Sex: Female, Male Male	79 Participants n=5 Participants	35 Participants n=7 Participants	30 Participants n=5 Participants	144 Participants n=4 Participants
Race/Ethnicity, Customized African American/African Heritage	11 Participants n=5 Participants	14 Participants n=7 Participants	13 Participants n=5 Participants	38 Participants n=4 Participants
Race/Ethnicity, Customized American Indian or Alaskan Native	2 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	2 Participants n=4 Participants
Race/Ethnicity, Customized Asian - Central/South Asian Heritage	1 Participants n=5 Participants	2 Participants n=7 Participants	1 Participants n=5 Participants	4 Participants n=4 Participants
Race/Ethnicity, Customized Asian - Japanese Heritage	3 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants	4 Participants n=4 Participants
Race/Ethnicity, Customized Asian - South East Asian Heritage	1 Participants n=5 Participants	2 Participants n=7 Participants	1 Participants n=5 Participants	4 Participants n=4 Participants
Race/Ethnicity, Customized Native Hawaiian or Other Pacific Islander	1 Participants n=5 Participants	0 Participants n=7 Participants	2 Participants n=5 Participants	3 Participants n=4 Participants
Race/Ethnicity, Customized White - Arabic /North African Heritage	1 Participants n=5 Participants	1 Participants n=7 Participants	0 Participants n=5 Participants	2 Participants n=4 Participants
Race/Ethnicity, Customized White - White/Caucasian/European Heritage	280 Participants n=5 Participants	131 Participants n=7 Participants	133 Participants n=5 Participants	544 Participants n=4 Participants
Race/Ethnicity, Customized Mixed Race	2 Participants n=5 Participants	1 Participants n=7 Participants	0 Participants n=5 Participants	3 Participants n=4 Participants
Race/Ethnicity, Customized Missing	0 Participants n=5 Participants	1 Participants n=7 Participants	0 Participants n=5 Participants	1 Participants n=4 Participants

PRIMARY outcome

Timeframe: From Baseline up to the Final Assessment Visit (FAV) (average of 609 days)

Population: mITT Population

Outcome measures

Outcome measures
Measure	Combination Therapy: Ambrisentan + Tadalafil n=253 Participants Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Monotherapy Pooled: Ambrisentan or Tadalafil n=247 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks; or one tablet of 20 mg TAD and one tablet of TAD-matching placebo QD for the first 4 weeks. For participants on TAD, the dose of TAD was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and for participants on AMB, the dose of AMB may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy n=126 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy n=121 Participants Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.
Number of Participants With First Adjudicated Clinical Failure (CF) Event, Death, Hospitalisation for Worsening PAH, Disease Progression, Unsatisfactory Long-term Clinical Response, All Through FAV First adjudicated clinical failure event	46 Participants	77 Participants	43 Participants	34 Participants
Number of Participants With First Adjudicated Clinical Failure (CF) Event, Death, Hospitalisation for Worsening PAH, Disease Progression, Unsatisfactory Long-term Clinical Response, All Through FAV Death (all-cause)	9 Participants	8 Participants	2 Participants	6 Participants
Number of Participants With First Adjudicated Clinical Failure (CF) Event, Death, Hospitalisation for Worsening PAH, Disease Progression, Unsatisfactory Long-term Clinical Response, All Through FAV Hospitalization for worsening PAH	10 Participants	30 Participants	18 Participants	12 Participants
Number of Participants With First Adjudicated Clinical Failure (CF) Event, Death, Hospitalisation for Worsening PAH, Disease Progression, Unsatisfactory Long-term Clinical Response, All Through FAV Disease progression	10 Participants	16 Participants	12 Participants	4 Participants
Number of Participants With First Adjudicated Clinical Failure (CF) Event, Death, Hospitalisation for Worsening PAH, Disease Progression, Unsatisfactory Long-term Clinical Response, All Through FAV Unsatisfactory long-term clinical response	17 Participants	23 Participants	11 Participants	12 Participants

SECONDARY outcome

Timeframe: Baseline and Week 24

Population: mITT Population. Only participants with data available at the specified time points were analyzed.

N-Terminal Pro-B-Type Natriuretic Peptide (NT-proBNP) is a surrogate marker of heart failure. The data were log-transformed. The geometric mean was calculated (based on the log-transformed data). The geometric mean ratio was calculated as the ratio between the Week 24 value and the Baseline value (based on the log-transformed data) and presented as percent change = 100 \* (geometric mean ratio - 1). The Baseline value is the last value prior to administration of study drug; this may be prior to or on the day of study drug initiation. No imputation was performed for missing data. The secondary endpoints were analyzed according to a pre-specified hierarchical testing procedure.

Outcome measures

Outcome measures
Measure	Combination Therapy: Ambrisentan + Tadalafil n=204 Participants Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Monotherapy Pooled: Ambrisentan or Tadalafil n=199 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks; or one tablet of 20 mg TAD and one tablet of TAD-matching placebo QD for the first 4 weeks. For participants on TAD, the dose of TAD was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and for participants on AMB, the dose of AMB may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy n=99 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy n=100 Participants Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.
Percent Change From Baseline in the N-Terminal Pro-B-Type Natriuretic Peptide at Week 24	-67.15 Percent change Standard Error 0.069	-50.37 Percent change Standard Error 0.070	-56.15 Percent change Standard Error 0.096	-43.83 Percent change Standard Error 0.095

SECONDARY outcome

Timeframe: Baseline and Week 24

Population: mITT Population. Only those participants who had a "Yes"/"No" response were analyzed.

A satisfactory clinical response at Week 24 is defined as a participant who meets all of the following criteria: 10% improvement in 6MWD compared with Baseline; improvement to or maintenance of World Health Organization (WHO) class I or II symptoms; no events of clinical worsening prior to or at the Week 24 visit. Clinical worsening events included: death, hospitalization for pulmonary arterial hypertension (PAH), and disease progression. Participants without an event of clinical worsening prior to or at the Week 24 visit who did not have a 6MWD value or a WHO functional class value at Week 24 were excluded from the analysis.

Outcome measures

Outcome measures
Measure	Combination Therapy: Ambrisentan + Tadalafil n=234 Participants Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Monotherapy Pooled: Ambrisentan or Tadalafil n=226 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks; or one tablet of 20 mg TAD and one tablet of TAD-matching placebo QD for the first 4 weeks. For participants on TAD, the dose of TAD was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and for participants on AMB, the dose of AMB may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy n=113 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy n=113 Participants Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.
Percentage of Participants With a Satisfactory Clinical Response at Week 24	39 Percentage of participants	29 Percentage of participants	31 Percentage of participants	27 Percentage of participants

SECONDARY outcome

Timeframe: Baseline and Week 24

Population: mITT Population. Only participants with Baseline data were analyzed.

The 6-minute walk distance (6MWD) test measures the distance that a participant can walk in a period of 6 minutes. Change from Baseline was calculated as the Week 24 value minus the Baseline value. The analysis was performed based on last observation carried forward data, except in the case of an adjudicated clinical failure event of death or hospitalization preceding the missing data observation. In this case, the missing observation was assigned the worst-rank score relative to those actually observed and was assigned a rank reflecting the relative order of the actual event times. Baseline 6MWD comprised of an average of the last two consecutive measurements prior to randomization that varied by no greater than 10%. If only one measurement was available, that measurement was used. If no two consecutive measures vary by no greater than 10% then Baseline was based on the last two consecutive measures for a participant.

Outcome measures

Outcome measures
Measure	Combination Therapy: Ambrisentan + Tadalafil n=248 Participants Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Monotherapy Pooled: Ambrisentan or Tadalafil n=244 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks; or one tablet of 20 mg TAD and one tablet of TAD-matching placebo QD for the first 4 weeks. For participants on TAD, the dose of TAD was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and for participants on AMB, the dose of AMB may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy n=124 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy n=120 Participants Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.
Change From Baseline in the 6 Minute Walk Distance Test at Week 24	48.98 Meters Interval 39.0 to 57.5	23.80 Meters Interval 19.0 to 33.5	27.00 Meters Interval 12.5 to 38.0	22.70 Meters Interval 16.5 to 35.5

SECONDARY outcome

Timeframe: Baseline and Week 24

Population: mITT Population. Only participants with Baseline data were analyzed.

The WHO Functional Class (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). Baseline WHO FC is the latest assessment prior to dosing (i.e., at Randomization or Screening). Change from Baseline at Week 24 was calculated as the Week 24 value minus the Baseline value. The analysis was performed based on the last observation carried forward data, except in the case of an adjudicated clinical failure event of death or hospitalization preceding the missing data observation. In this case, the missing observations was assigned the worst-rank score relative to those actually observed and was assigned rank reflecting the relative order of the actual event times.

Outcome measures

Outcome measures
Measure	Combination Therapy: Ambrisentan + Tadalafil n=252 Participants Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Monotherapy Pooled: Ambrisentan or Tadalafil n=244 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks; or one tablet of 20 mg TAD and one tablet of TAD-matching placebo QD for the first 4 weeks. For participants on TAD, the dose of TAD was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and for participants on AMB, the dose of AMB may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy n=124 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy n=120 Participants Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.
Change From Baseline in the World Health Organization Functional Class at Week 24	0.0 Scores on a scale Interval -1.0 to 0.0	0.0 Scores on a scale Interval -1.0 to 0.0	0.0 Scores on a scale Interval -1.0 to 0.0	0.0 Scores on a scale Interval -1.0 to 0.0

SECONDARY outcome

Timeframe: Baseline (BL) and Week 24

Population: mITT Population. Only participants with Baseline data were analyzed.

Borg Dyspnea Index (BDI) indicates the degree of breathlessness after completion of the 6 minute walk test. The BDI was calculated by using the Borg category (C) ratio (R) CR10 scale which starts at 0 (nothing at all) and has no upper limit (extremely strong). Change from BL was calculated as the Week 24 values minus the BL value. The BDI scale was assessed by each participant. The BL BDI score is the average of the two BDI values obtained following the two 6MWD tests used in determining the BL 6MWD. A negative change from BL in the BDI score represented an improvement for the participant. The analysis was performed based on the last observation carried forward data, except in the case of an adjudicated clinical failure event of death or hospitalization preceding the missing data observation. In this case, the missing observation was assigned the worst-rank score relative to those actually observed and was assigned rank reflecting the relative order of the actual event times.

Outcome measures

Outcome measures
Measure	Combination Therapy: Ambrisentan + Tadalafil n=247 Participants Participants initially received one tablet of 5 milligrams (mg) ambrisentan (AMB) and one tablet of AMB matching placebo once daily (QD) for the first 8 weeks plus one tablet of 20 mg tadalafil (TAD) and one tablet of TAD matching placebo QD for the first 4 weeks. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and the AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Monotherapy Pooled: Ambrisentan or Tadalafil n=244 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks; or one tablet of 20 mg TAD and one tablet of TAD-matching placebo QD for the first 4 weeks. For participants on TAD, the dose of TAD was uptitrated to 40 mg (two tablets of 20 mg QD) after 4 weeks and for participants on AMB, the dose of AMB may have been uptitrated to 10 mg (two tablets of 5 mg QD) after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Ambrisentan Monotherapy n=124 Participants Participants initially received one tablet of 5 mg AMB and one tablet of AMB matching placebo QD for the first 8 weeks plus two tablets of TAD matching placebo. The AMB dose may have been uptitrated to 10 mg (two tablets of 5 mg QD) and two tablets of TAD matching placebo after 8 weeks. The uptitration of AMB to 10 mg was not mandatory if the investigator decided for tolerability reasons the participants should remain on 5 mg.	Tadalafil Monotherapy n=120 Participants Participants initially received one tablet of 20 mg TAD and one tablet of TAD matching placebo QD for the first 4 weeks plus two tablets of AMB matching placebo. The TAD dose was uptitrated to 40 mg (two tablets of 20 mg QD) and two tablets of AMB matching placebo after 4 weeks.
Change From Baseline in Borg Dyspnea Index at Week 24	-1.00 Scores on a scale Interval -2.0 to 0.5	-0.50 Scores on a scale Interval -1.5 to 0.5	-0.50 Scores on a scale Interval -1.5 to 0.5	-0.50 Scores on a scale Interval -2.0 to 0.88

Adverse Events

Combination Therapy: Ambrisentan + Tadalafil

Serious events: 124 serious events

Other events: 279 other events

Deaths: 0 deaths

Ambrisentan Monotherapy

Serious events: 63 serious events

Other events: 140 other events

Deaths: 0 deaths

Tadalafil Monotherapy

Serious events: 68 serious events

Other events: 135 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Additional Information

GSK Response Center

GlaxoSmithKline

Phone: 866-435-7343

Results disclosure agreements

Principal investigator is a sponsor employee GSK agreements may vary with individual investigators, but will not prohibit any investigator from publishing. GSK supports the publication of results from all centers of a multi-center trial but requests that reports based on single-site data not precede the primary publication of the entire clinical trial.
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