An Open-Label Uncontrolled Study of the Safety and Efficacy of Ambrisentan in Patients With Exercise Induced Pulmonary Arterial Hypertension

Exercised Induce Pulmonary Arterial Hypertension (EIPAH) population: These patients may
provide a unique window into the pathogenesis of PAH. Our data suggest that these patients
may represent an early phase of PAH with an abnormal vascular response.

The study includes an assessment of the potential impact of ambrisentan on exercise capacity
Advanced Level-3 CPET, and New York Heart Association (NYHA) functional class.

Inclusion Criteria:

- The subject provides written informed consent before the commencement of any study
related procedure.

- The subject is 18 years of age or older.

- If a female subject of child-bearing potential, the subject must agree to use 2 forms
of contraceptive therapy, including at least 1 barrier method, throughout the study
and follow-up. (Women who are surgically sterile or those post-menopausal for at
least 2 years are not considered to be of childbearing potential.)

- The subject has findings of either exercise induced PAH on a Advanced Level -3 CPET
performed within the last 6-months and is a NYHA Class I or II.

- The subject has an LVEF 55%, obtained by any appropriate method (i.e., ECHO,
radionuclide imaging, or cardiac catheterization)

- The subject is taking a stable concomitant medication regimen for at least 4 weeks
prior to enrollment in the study that is not expected to change during the study
period and follow-up. Changes in diuretic and/or nitrate therapy as needed during the
study period are acceptable.