Patient Global Impression Questions for Activity-induced Symptoms in Patients With PAH

This is an observational, multicenter, single-day, Phase 2 study. This study will include a
14-day Screening Period and Study Day 1 clinic visit. Participants will be required to
perform an activity to induce symptoms of PAH, and subjects' severity of self-reported
symptoms of PAH will be measured from pre-activity, immediately after the activity, and
through the 30-minute recovery. Participants will be asked about their PAH symptoms using 3
PGI-S questions that address their overall PAH symptoms, shortness of breath, and physical
fatigue.

PAH symptoms will be induced via the Incremental Shuttle Walk Test (ISWT).

The total number of shuttles completed by a participant during the Screening ISWT will be the
maximum targeted for that participant during the remaining ISWTs in the study.

After Screening, participants will be assigned to 1 of 2 cohorts based on PAH medications as
prescribed by their physician: Cohort A will include participants who are currently
prescribed and using inhaled treprostinil for the treatment of PAH and Cohort B will include
participants who are taking other PAH medications (instead of inhaled treprostinil).

The baseline PGI-S and Borg dyspnea score assessments will be conducted prior to (-15 and 0
minutes; pre-ISWT) activity that is typically expected to induce symptoms of PAH. The
participant will initiate activity (ISWT), and these same assessments will be performed
immediately at the end of the ISWT (within 1 minute of completing the activity). The PGI-S
assessments will also be performed throughout recovery following completion of the ISWT.
Continuous pulse oximetry will be performed at each clinic visit starting at each pre-ISWT
and through recovery. Vital sign assessments will be performed at the beginning and at the
end of each clinic visit.

Inclusion Criteria:

1. Subject voluntarily gives informed consent to participate in the study.

2. Males and females aged 18 years and above at the time of informed consent.

3. Established primary diagnosis of PAH that is either idiopathic or familial PAH (WHO
Group 1), collagen vascular disease associated PAH, PAH associated with human
immunodeficiency virus (HIV) infection, PAH induced by anorexigens/toxins, or PAH
associated with repaired congenital systemic-to-pulmonary shunts (repaired ≥1 years).

4. Subject is deemed WHO Functional Class I, II, or III.

5. Subject has shortness of breath upon exertion (exhibits a ≥1-point change in Borg
dyspnea score) as assessed by the ISWT and a minimum completion of 3 shuttles (30
meters) of the ISWT. Subject may have other symptoms as well.

6. Subject is on stable dose of all FDA-approved PAH treatments (exceptions are
anticoagulants and diuretics) for at least 60 days prior to Screening.

7. In the opinion of the Investigator, the subject can communicate effectively with study
personnel, and is considered reliable, willing, and likely to be cooperative with
protocol requirements.

Exclusion Criteria:

1. The subject is known to be pregnant or nursing.

2. The subject has PAH related to any condition not covered under inclusion criteria,
including, but not limited to, pulmonary venous hypertension, pulmonary venoocclusive
disease, pulmonary capillary hemangiomatosis, chronic thromboembolic pulmonary
hypertension, or other conditions under WHO Group 2, 3, 4, and 5 classifications.

3. The subject has evidence of clinically significant left-sided heart disease
(including, but not limited to, left ventricular ejection fraction <40%, left
ventricular hypertrophy) or clinically significant cardiologic conditions, such as
congestive heart failure, coronary artery disease, or valvular heart disease.

4. The subject has any form of congenital heart disease (repaired or unrepaired; other
than a patent foramen ovale).

5. The subject has any ambulatory or orthopedic limitations that would interfere with the
ability to perform the activity.

6. The subject has been hospitalized within 30 days of Screening.

7. Current use of prostacyclin analogs/agonists, except inhaled treprostinil, for the
treatment of PAH.

8. Use of any other investigational drug/device, or participation in any investigational
study with therapeutic intent within 30 days of Screening (concurrent participation in
registry studies is allowed).

9. Any other clinically significant illness that, in the opinion of the Investigator,
might put the subject at risk of harm during the study or might adversely affect the
interpretation of the study data.