Evaluation of Metformin Activity in Addition to Conventional Treatment of Grade II or III Pulmonary Arterial Hypertension (PAH)

Treatment of PAH includes exercise limitation, non specific agents (anticoagulants, diuretics and supplemental oxygen), pulmonary specific vasodilators and antiproliferative agents.

Recent data obtained by our group, within rat PAH models, showed that the antihyperglycemic drug metformin, used in France since 1959 in diabetic type II patients, significantly acts at the pulmonary arteries level.

According to these results, and knowing that metformin is a widely used drug, with a favorable safety profile, the investigators decided to set up a pilot study, in order to evaluate the activity of metformin in PAH treatment. In parallel, the investigators will focus on metformin mechanism of action.

Inclusion Criteria:

• Men or women aged between 18 and 80
• Patients included will have pre-capillary PAH
• they have to be stable for more than 3 months
• Patient with a 6-minute walk test comparable over the last 3 months before inclusion
• Informed consent signed