Anastrozole in Patients With Pulmonary Arterial Hypertension

Inclusion Criteria:

- Previous documentation of mean pulmonary artery pressure > 25 mm Hg with a pulmonary
capillary wedge pressure (or left ventricular end-diastolic pressure) < 16 mm Hg and
PVR > 3 WU at any time before study entry.

- Diagnosis of PAH which is idiopathic, heritable, drug- or toxin-induced, or
associated with connective tissue disease, congenital heart disease, portal
hypertension, or HIV infection.

- Most recent pulmonary function tests with FEV1/FVC >50% AND either a) total lung
capacity > 70% predicted or b) total lung capacity between 60% and 70% predicted with
no more than mild interstitial lung disease on computerized tomography scan of the
chest

- Ability to perform six minute walk testing without limitations in musculoskeletal
function or coordination.

- If female, post-menopausal state, defined as:

- > 50 years old AND

- a) have not menstruated during the preceding 12 months OR

- b) have follicle-stimulating hormone (FSH) levels (> 40 IU/L) OR

- < 50 years and FSH (> 40 IU/L) OR

- having had a bilateral oophorectomy

- Informed consent

Exclusion Criteria:

- Treatment with estrogen or anti-hormone therapy (tamoxifen, fulvestrant, etc.)

- WHO Class IV functional status

- History of breast cancer

- Clinically significant untreated sleep apnea

- Left-sided valvular disease (more than moderate mitral valve stenosis or
insufficiency or aortic stenosis or insufficiency), pulmonary artery or valve
stenosis, or ejection fraction < 45% on echocardiography

- Initiation of PAH therapy (prostacyclin analogues, endothelin-1 receptor antagonists,
phosphodiesterase-5 inhibitors) within three months of enrollment; the dose must be
stable for at least 3 months prior to Baseline Visit

- Hormone therapy

- Hospitalized or acutely ill

- Renal failure (creatinine > 2.0)

- Child-Pugh Class C cirrhosis

- Current or recent (< 6 months) chronic heavy alcohol consumption

- Current use of another investigational drug (non-FDA approved) for PAH

- Enrollment in a clinical trial within one month of screening

- Age < 18