Clinical Study to Assess the Safety, Tolerability and Efficacy of Macitentan in Subjects With Inoperable Chronic Thromboembolic Pulmonary Hypertension

Inclusion Criteria:

- Written informed consent

- Subject with CTEPH having completed the double-blind (DB) AC-055E201/ MERIT-1 study
as scheduled (i.e., who remained in the DB study up to Week 24).

- Females of childbearing potential must have a negative pre-treatment serum pregnancy
test, be advised on appropriate methods of contraception, and agree to use 2 reliable
methods of contraception.

Exclusion Criteria:

- Permanent discontinuation of DB study treatment due to an hepatic adverse event or
liver aminotransferase abnormalities.

- Any known factor (e.g., drug or substance abuse) or disease (e.g., unstable
psychiatric illness) that, in the opinion of the investigator, may interfere with
treatment compliance or interpretation of the results, or that may influence the
ability to comply with any of the study requirements.