A Phase 3 Study to Evaluate the Safety and Tolerability of L606 in Subjects With PAH or PH-ILD

This Phase 3, 2-part, open-label, multicenter study aims to demonstrate the safety and tolerability of repeated doses of L606 in patients with PAH or PH-ILD. Cohort A: Subjects with PAH or PH-ILD receiving prior stable doses of Tyvaso and willing to switch to L606. Cohort B: Subjects with PAH (not initially on prostacyclin therapy) who are likely to receive clinical benefit from inhaled treprostinil based on the opinion of the investigator. Cohort A subjects will sequentially participate in the Main Study Period (MSP) for 2 weeks and the Open Extension Period (OEP) for 46 weeks. Cohort B subjects will sequentially participate in the MSP for 12 weeks and the OEP for 36 weeks.