Pulmonary artery hypertension (PAH) is a chronic and progressive disease that affects 15 persons per million. Although current therapy has improve disease prognosis, PAH still has a poor survival, with a median survival of 2.8 years after diagnosis. In the last few years new key elements in PAH pathogenesis have been discovered, such as the role of metabolism in disease onset and progression. In fact, PAH pulmonary smooth muscle cells switch into a glycolytic phenotype which resembles the metabolism of cancer cells. The investigators hypothesis is that "fatty acid oxidation inhibition reverts the PAH adverse phenotype by restoring mitochondrial function and morphology, decreasing proliferation and restoring apoptosis susceptibility in pulmonary smooth muscle cells "

Inclusion Criteria:

• PAH patients belonging to the following subgroups of the updated Dana Point Classification Group 1

  1. Idiopathic PAH
  2. Heritable PAH
  3. Drug or toxin-induced PAH
  4. PAH associated with connective tissue disease
  5. PAH associated to congenital heart disease with simple systemic-to-pulmonary shunt at least 1 year after surgical repair
  6. PAH associated to HIV infection

• Documented hemodynamic diagnosis of PAH by right ventricular catheterization performed any time prior to screening

• Signed informed consent

Exclusion Criteria:

• Patients belonging to the subgroups of the updated Dana Point Classification Group I not listed in the inclusion criteria
• Patients belonging to the groups 2-5 of the updated Dana Point Classification Group
• Moderate to severe chronic pulmonary obstructive disease
• Documented left ventricular dysfunction
• Severe renal impairment (Serum creatinine > 2.5 mg/dL)
• Patients who are receiving or have been receiving any investigational drugs within 1 month before the baseline visit
• Acute or chronic impairment (other than dyspnea) limiting the ability to comply with study requirements
• Psychotic, addictive or other disorder limiting the ability to provide informed consent or to comply with study requirements
• Life expectancy less than 12 months
• Females who are lactating or pregnant or those who plan to become pregnant during the study
• Known hypersensitivity to any of the excipients of the drug formulation