Extension Study of Inhaled Treprostinil in Subjects With Fibrotic Lung Disease

Inclusion Criteria: 1. Subject gives voluntary informed consent to participate in the study. 2. The subject participated in Study RIN-PF-301, Study RIN-PF-303, or Study RIN-PF-305 and remained on study drug and completed all scheduled study visits or was enrolled in Study RIN-PF-301, Study RIN-PF-303, or Study RIN-PF-305 at the time that the study or study subject was discontinued by the Sponsor for reasons other than safety. 3. Women of childbearing potential must be non-pregnant (as confirmed by a urine pregnancy test at OLE Entry Visit) and non-lactating, and will agree to abstain from intercourse (when it is in line with their preferred and usual lifestyle) or use 2 medically acceptable, highly effective forms of contraception for the duration of the study, and at least 30 days after discontinuing study drug. 4. Males with a partner of childbearing potential must agree to use a condom for the duration of treatment and for at least 48 hours after discontinuing study drug. 5. In the opinion of the Investigator, the subject is able to communicate effectively with study personnel, and is considered reliable, willing, and likely to be cooperative with protocol requirements, including attending all study visits. Exclusion Criteria: 1. Subject is pregnant or lactating. 2. In the opinion of the Investigator, enrollment in Study RIN-PF-302 would represent a risk to the subject's overall health. 3. Use of any other investigational drug/device or participation in any investigational study in which the subject received a medical intervention (ie, procedure, device, medication/supplement). Subjects participating in non-interventional, observational, or registry studies are eligible.