GlaxoSmithKline (GSK) is embarking on a clinical program to assess the treatment of PAH with an Angiotensin converting enzyme 2 (ACE2). This new treatment may require subcutaneous administration, in comparison to current treatments which are taken orally. Hence, GSK would like to conduct this qualitative interview study with PAH subjects to explore subject's perspective and preferences for various modes of treatment administration (daily or weekly subcutaneous injection versus current treatment options). This will be a qualitative study comprising the conduct of semi-structured telephone concept elicitation interviews with 8 to 10 PAH subjects (each approximately 30 minutes in duration) in the United States (US).

Inclusion Criteria:

• Male or female, at least 18 years of age.
• Subject is willing and able to provide written informed consent.
• Subject must have a diagnosis of symptomatic Pulmonary Arterial Hypertension Type I as per the World Health Organization (WHO) clinical classification system.
• Subject must have the cognitive and linguistic capabilities sufficient to allow them to actively participate in an interview lasting 30 minutes.

Exclusion Criteria:

• Subject has a diagnosis of other cardiac or pulmonary disease.
• Subject has a Type II-V diagnosis of PAH, as per the WHO clinical classification system.
• Subject is currently receiving treatment for PAH via modes of administration other than intravenously or orally.

A sample of 8 to 10 US-English speaking subjects will be recruited. Recruitment will be facilitated by a third-party vendor in the US. A purposive approach to sampling will be employed to ensure subjects with a range of demographic and clinical characteristics are recruited.