Ambrisentan for the treatment of pulmonary arterial hypertension: results of the ambrisentan in pulmonary arterial hypertension, randomized, double-blind, placebo-controlled, multicenter, efficacy (ARIES) study 1 and 2.
BACKGROUND
Ambrisentan is a propanoic acid-based, A-selective endothelin receptor antagonist for the once-daily treatment of pulmonary arterial hypertension.


RESULTS
Ambrisentan in Pulmonary Arterial Hypertension, Randomized, Double-Blind, Placebo-Controlled, Multicenter, Efficacy Study 1 and 2 (ARIES-1 and ARIES-2) were concurrent, double-blind, placebo-controlled studies that randomized 202 and 192 patients with pulmonary arterial hypertension, respectively, to placebo or ambrisentan (ARIES-1, 5 or 10 mg; ARIES-2, 2.5 or 5 mg) orally once daily for 12 weeks. The primary end point for each study was change in 6-minute walk distance from baseline to week 12. Clinical worsening, World Health Organization functional class, Short Form-36 Health Survey score, Borg dyspnea score, and B-type natriuretic peptide plasma concentrations also were assessed. In addition, a long-term extension study was performed. The 6-minute walk distance increased in all ambrisentan groups; mean placebo-corrected treatment effects were 31 m (P=0.008) and 51 m (P<0.001) in ARIES-1 for 5 and 10 mg ambrisentan, respectively, and 32 m (P=0.022) and 59 m (P<0.001) in ARIES-2 for 2.5 and 5 mg ambrisentan, respectively. Improvements in time to clinical worsening (ARIES-2), World Health Organization functional class (ARIES-1), Short Form-36 score (ARIES-2), Borg dyspnea score (both studies), and B-type natriuretic peptide (both studies) were observed. No patient treated with ambrisentan developed aminotransferase concentrations >3 times the upper limit of normal. In 280 patients completing 48 weeks of treatment with ambrisentan monotherapy, the improvement from baseline in 6-minute walk at 48 weeks was 39 m.


CONCLUSIONS
Ambrisentan improves exercise capacity in patients with pulmonary arterial hypertension. Improvements were observed for several secondary end points in each of the studies, although statistical significance was more variable. Ambrisentan is well tolerated and is associated with a low risk of aminotransferase abnormalities.
Galiè
Nazzareno
N
Institute of Cardiology, University of Bologna, Via Massarenti, 9, 40138-Bologna, Italy. nazzareno.galie@unibo.it
Olschewski
Horst
H
Oudiz
Ronald J
RJ
Torres
Fernando
F
Frost
Adaani
A
Ghofrani
Hossein A
HA
Badesch
David B
DB
McGoon
Michael D
MD
McLaughlin
Vallerie V
VV
Roecker
Ellen B
EB
Gerber
Michael J
MJ
Dufton
Christopher
C
Wiens
Brian L
BL
Rubin
Lewis J
LJ
D000203:Activities of Daily Living; D000284:Administration, Oral; D000368:Aged; D004311:Double-Blind Method; D004417:Dyspnea; D065128:Endothelin Receptor Antagonists; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy* / Q000503:physiopathology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010666:Phenylpropionates / Q000008:administration & dosage* / Q000009:adverse effects; D010919:Placebos; D011724:Pyridazines / Q000008:administration & dosage* / Q000009:adverse effects; D011788:Quality of Life; D016896:Treatment Outcome
D065128:Endothelin Receptor Antagonists; D010666:Phenylpropionates; D010919:Placebos; D011724:Pyridazines; D020097:Natriuretic Peptide, Brain; C467894:ambrisentan