| E.1 Medical condition or disease under investigation | 
| E.1.1 | Medical condition(s) being investigated | 
| Pulmonary arterial hypertension (PAH) |  | 
| E.1.1.1 | Medical condition in easily understood language |  | 
| E.1.1.2 | Therapeutic area | Diseases [C] - Cardiovascular Diseases [C14] | 
| MedDRA Classification | 
| E.1.2 Medical condition or disease under investigation | 
| 
| E.1.2 | Version | 20.0 |  
| E.1.2 | Level | LLT |  
| E.1.2 | Classification code | 10077731 |  
| E.1.2 | Term | Pulmonary hypertension WHO functional class I |  
| E.1.2 | System Organ Class | 100000004855 |  | 
| E.1.3 | Condition being studied is a rare disease | No | 
| E.2 Objective of the trial | 
| E.2.1 | Main objective of the trial | 
| The primary objective of this study is: To evaluate the long-term safety and tolerability of ralinepag (APD811)
 in subjects who have participated in a preceding Phase 2 or Phase 3
 study of ralinepag.
 |  | 
| E.2.2 | Secondary objectives of the trial | 
| The secondary objectives of the study are to evaluate the long-term effects of ralinepag on the following parameters:
 • N-terminal pro-brain natriuretic peptide (NT-proBNP)
 • 6-Minute Walk Distance (6MWD)
 • WHO/New York Heart Association (NYHA) Functional Class (FC)
 • Health-related quality of life (HRQoL) measures
 • Time to all-cause hospitalization
 • Time to all-cause mortality
 |  | 
| E.2.3 | Trial contains a sub-study | Yes | 
| E.2.3.1 | Full title, date and version of each sub-study and their related objectives | 
| A pharmacokinetic (PK) substudy is planned at selected sites. Approximately 70 subjects who consented to participate will enroll in the
 PK substudy. Collected plasma PK samples may be used for profiling of
 drug binding proteins, bioanalytical method validation purposes, stability
 assessments, metabolite assessments, or to assess other actions of
 ralinepag with plasma constituents.
 |  | 
| E.3 | Principal inclusion criteria | 
| Each subject must meet ALL of the following inclusion criteria to be eligible for enrollment into the study:
 1. Evidence of a personally signed and dated Informed Consent Form
 indicating that the subject has been informed of all pertinent aspects of
 the study prior to initiation of any study-related procedures.
 2. Subjects who are willing and able to comply with scheduled visits,
 treatment plan, laboratory tests, and other study procedures.
 3. Completed the protocol-defined Study Drug Termination Visit or End of
 Study Visit procedures in the preceding ralinepag study.
 4. Both male and female subjects agree to use a highly effective method
 of birth control throughout the entire study period from informed
 consent through the 30-Day Follow-up Visit, if the possibility of
 conception exists. Eligible male and female subjects must also agree not
 to participate in a conception process (ie, actively attempt to become
 pregnant or to impregnate; sperm donation; in vitro fertilization) during
 the study and for 30 days after the last dose of ralinepag.
 
 |  | 
| E.4 | Principal exclusion criteria | 
| Eligible subjects must not meet ANY of the following exclusion criteria to be eligible for enrollment into the study:
 1. Subjects who prematurely discontinued investigational medicinal
 product (IMP) due to a drug-related AE/SAE or tolerability issue in the
 preceding ralinepag study in which they were enrolled, or subjects who
 did not complete all protocol-defined study procedures at a Study Drug
 Termination Visit or End of Study Visit in the preceding ralinepag study.
 2. Subjects who withdrew consent during participation in another
 ralinepag study.
 3. Female subjects who wish to become pregnant or who have a positive
 pregnancy test on Day 1 (OLE Entry Visit).
 4. Women who are pregnant, lactating, or breastfeeding
 5. Subjects who have undergone lung or heart/lung transplant or are
 receiving longterm parenteral (intravenous [IV] or subcutaneous [SC]
 infusion) or inhaled therapy with a prostacyclin or oral therapy with
 another IP receptor agonist during the time since participation in their
 original ralinepag study.
 6. Male subjects with a corrected QT interval using Fridericia's formula
 (QTcF) >450 msec and female subjects with QTcF >470 msec on
 electrocardiogram (ECG) recorded within 12 weeks prior to Day 1.
 7. Subjects who had an emergency unblinding procedure in a prior Phase
 2 or 3 ralinepag study.
 8. Known hypersensitivity to ralinepag or any of the excipients.
 9. Any reason that, in the opinion of the Investigator or Medical Monitor,
 precludes the subject from participating in the study, eg, noncompliance
 concerns, any previous or intercurrent medical condition that may
 increase the risk associated with study participation or that would
 confound study analysis or impair study participation or cooperation.
 |  | 
| E.5 End points | 
| E.5.1 | Primary end point(s) | 
| Efficacy assessments will include an evaluation of: • NT-proBNP
 • 6MWD
 • WHO/NYHA FC
 • The proportion of subjects who achieve all 3 of the following (at
 specified time points):
 . NT-proBNP level <300 pg/mL
 . 6MWD >440 meters
 . WHO/NYHA FC II status or better
 • HRQoL measures (where validated)
 • Time to all-cause hospitalization during the study period
 • Time to all-cause mortality during the study period
 |  | 
| E.5.1.1 | Timepoint(s) of evaluation of this end point | 
| Continuous endpoints (NT-proBNP, 6MWD, and HRQoL) and changes from baseline will be summarized by visit.
 |  | 
| E.5.2 | Secondary end point(s) |  | 
| E.5.2.1 | Timepoint(s) of evaluation of this end point |  | 
| E.6 and E.7 Scope of the trial | 
| E.6 | Scope of the trial | 
| E.6.1 | Diagnosis | No | 
| E.6.2 | Prophylaxis | No | 
| E.6.3 | Therapy | Yes | 
| E.6.4 | Safety | Yes | 
| E.6.5 | Efficacy | Yes | 
| E.6.6 | Pharmacokinetic | Yes | 
| E.6.7 | Pharmacodynamic | No | 
| E.6.8 | Bioequivalence | No | 
| E.6.9 | Dose response | No | 
| E.6.10 | Pharmacogenetic | No | 
| E.6.11 | Pharmacogenomic | No | 
| E.6.12 | Pharmacoeconomic | No | 
| E.6.13 | Others | No | 
| E.7 | Trial type and phase | 
| E.7.1 | Human pharmacology (Phase I) | No | 
| E.7.1.1 | First administration to humans | No | 
| E.7.1.2 | Bioequivalence study | No | 
| E.7.1.3 | Other | No | 
| E.7.1.3.1 | Other trial type description |  | 
| E.7.2 | Therapeutic exploratory (Phase II) | No | 
| E.7.3 | Therapeutic confirmatory (Phase III) | Yes | 
| E.7.4 | Therapeutic use (Phase IV) | No | 
| E.8 Design of the trial | 
| E.8.1 | Controlled | No | 
| E.8.1.1 | Randomised | No | 
| E.8.1.2 | Open | Yes | 
| E.8.1.3 | Single blind | No | 
| E.8.1.4 | Double blind | No | 
| E.8.1.5 | Parallel group | No | 
| E.8.1.6 | Cross over | No | 
| E.8.1.7 | Other | Yes | 
| E.8.1.7.1 | Other trial design description |  | 
| E.8.2 | Comparator of controlled trial | 
| E.8.2.1 | Other medicinal product(s) | No | 
| E.8.2.2 | Placebo | No | 
| E.8.2.3 | Other | No | 
| E.8.2.4 | Number of treatment arms in the trial | 1 | 
| E.8.3 | The trial involves single site in the Member State concerned | No | 
| E.8.4 | The trial involves multiple sites in the Member State concerned | Yes | 
| E.8.4.1 | Number of sites anticipated in Member State concerned | 3 | 
| E.8.5 | The trial involves multiple Member States | Yes | 
| E.8.5.1 | Number of sites anticipated in the EEA | 67 | 
| E.8.6 Trial involving sites outside the EEA | 
| E.8.6.1 | Trial being conducted both within and outside the EEA | Yes | 
| E.8.6.2 | Trial being conducted completely outside of the EEA | No | 
| E.8.6.3 | If E.8.6.1 or E.8.6.2 are Yes, specify the regions in which trial sites are planned | 
| Argentina |  
| Australia |  
| Brazil |  
| Canada |  
| Chile |  
| China |  
| Israel |  
| Korea, Republic of |  
| Mexico |  
| Singapore |  
| Taiwan |  
| Thailand |  
| United States |  
| European Union |  
| Turkey |  
| Ukraine |  
| Serbia |  | 
| E.8.7 | Trial has a data monitoring committee | Yes | 
| E.8.8 | Definition of the end of the trial and justification where it is not the last
                        visit of the last subject undergoing the trial |  | 
| E.8.9 Initial estimate of the duration of the trial | 
| E.8.9.1 | In the Member State concerned years | 6 | 
| E.8.9.1 | In the Member State concerned months |  | 
| E.8.9.1 | In the Member State concerned days |  | 
| E.8.9.2 | In all countries concerned by the trial years | 6 |