This is a research study involving an investigational drug called RT234. RT234 is being developed to treat pulmonary arterial hypertension (PAH). Eligible subjects must have a confirmed diagnosis of PAH and be on stable disease-specific PAH background therapy. The purpose of this study is to collect more information about the ability of RT234 to improve exercise capacity and safety of RT234 for the treatment of pulmonary arterial hypertension. The total duration of participation in the study, including screening, will be up to 4 study visits and a follow-up telephone call, over a period of up to 14 weeks. Up to 60 subjects will take part in this study.

This is a Phase 2, double-blind, randomized, placebo-controlled study of KER-012 (study drug) compared to Placebo in adult participants with a primary diagnosis of Pulmonary Arterial Hypertension (PAH) on stable background PAH therapy. About 90 participants, in approximately 60 study centers worldwide, will take part in this study. Participation in this study may last up to 2 years and the study has a Screening period, Treatment period, Extension period, and Follow-up period.

This Phase 3 study, comprising a double-blind, placebo-controlled treatment period of up to 48 weeks, will assess the efficacy and safety of seralutinib versus placebo when added to background PAH disease-specific medication in adult PAH subjects who are WHO FC II or III. The primary objective of the study is to assess the efficacy of seralutinib relative to placebo with a primary endpoint of change from baseline to Week 24 in 6MWD.

This is a phase 4, prospective, multicenter, single-arm, open-label study designed
to evaluate the effect of early and rapid treprostinil therapy on mean pulmonary artery pressure (mPAP) reduction to improve Right ventricular (RV) function and reverse RV remodeling in patients with PAH. This study will use the CardioMEMS™ HF System (CardioMEMS) to measure and monitor mPAP, but may allow mPAP monitoring via RHC (right heart catheterization), if CardioMEMS is NOT available at a subject's Baseline Visit (Day 1) or if the CardioMEMS™ PA Sensor implantation is unsuccessful.

Participation is expected to be up to 37 months and will include about 10 office visits to the study doctor. This will be divided up into a 30-day Screening Period, a 12-month Treatment Period, and a 24-month Extended Treatment Period.

The objective of this study is to evaluate the effects of sotatercept treatment (plus background PAH therapy) verses placebo (plus background PAH therapy) on time to clinical worsening (TTCW) in participants who are newly diagnosed with PAH and are in intermediate or high risk of disease progression. The study is divided into a Screening Period (up to 4 weeks), followed by a Double-blind Placebo-controlled (DBPC) Treatment Period. When a participant experiences an event of clinical worsening, they will complete the End of Treatment (EOT) Visit and will be eligible to enroll immediately in the open-label, long-term follow-up (LTFU) study, A011-12 (SOTERIA). Up to 662 participants will be randomly assigned in a 1:1 ratio to the 2 study treatment groups (331 participants per arm).

This open-label, LTFU study will evaluate the safety, tolerability, and efficacy of sotatercept in participants with PAH previously treated with sotatercept or placebo. Participants eligible to enroll in this study will have participated in and completed the relevant study participants of the parent PAH sotatercept clinical trials. The estimated duration of the A011-12 study is up to 7 years; however, the estimated duration of enrollment for each participants is approximately 4 years. There is no formal sample size calculation for the study. The number of participants in this LTFU study is dependent upon the enrollment in the parent protocols. Approximately 700 participants are anticipated to enroll in the study.

The PHAR is a multicenter, prospective registry of newly evaluated patients at PHCCs in the United States who have either PAH or CTEPH. Baseline information will be collected at the time of initial evaluation at the PHCC (within six months of the initial outpatient PHCC visit) with follow-up data collected at approximately 6-month intervals. This study will determine how patients with PH are evaluated, tested, and treated, and will observe how well patients do. The goal of the project is to see if patients with PH are treated according to recommended guidelines and to see if there are certain factors which lead to better or worse outcomes in patients with PH. There is no intervention or study medication used and there is no limitation to how a patient is treated in this study.