A Study to Learn About the Treatment LTP001 in Healthy Participants (Part A) and in Participants With PAH (Part B)

Part A Inclusion Criteria: * Healthy males and non-child-bearing potential females Part A Exclusion Criteria: * Clinically significant ECG or cardiac abnormalities, any surgical or medical condition which might significantly alter the absorption, distribution, metabolism, or excretion of drugs, or which may jeopardize the participant in the study Other protocol-defined inclusion/exclusion criteria may apply. * For Japanese cohorts: participants per protocol should be first generation Japanese or up to third generation Japanese as defined in inclusion criteria 7 of the protocol. Part B Inclusion Criteria: -Confirmed diagnosis of PAH, pre-randomization PVR ≥400 dyn.sec.cm-5, treatment with stable doses of standard-of-care PAH therapies, 6-minute walk distance ≥ 150 m and ≤450 m. Part B Exclusion Criteria: Any surgical or medical condition which may place the participant at higher risk from his/her participation in the study Women of child-bearing potential unless they are using highly effective methods of contraception Sexually active males unwilling to use a condom during intercourse while taking study treatment and for 24 hours after stopping study treatment. History of hypersensitivity to any of the study treatments or excipients Other protocol-defined inclusion / exclusion criteria may apply