after completing the previous study you receive information about the extension and give written consent to take part.

once consent is provided you are assigned a study number and scheduled for the first baseline visit.

at the first visit a series of examinations are performed to record your health status before starting the medication.

measurements include vital signs (blood pressure, heart rate), a 12‑lead ecg, laboratory blood tests, assessment of supplemental oxygen use, a 6‑minute walk test (6mwd), lung function tests (forced vital capacity fvc and forced expiratory volume in 1 second fev1), and a blood sample for nt‑probnp level.

questionnaires that evaluate lung‑specific symptoms (l‑pf) and overall health status (eq‑5d‑5l) are also completed.

you receive treprostinil palmitil inhalation powder for daily use.

each dose contains 1280 µg of the active substance and is taken by inhalation according to the device instructions.

the first dose is administered under supervision of study staff to confirm correct technique.

every day you inhale the prescribed dose using the supplied inhaler.

you keep a simple diary noting the date and time of each inhalation, any symptoms, and any use of supplemental oxygen.

if a dose is missed you record the reason and inform the study team at the next visit.

follow‑up visits are scheduled approximately every 12 weeks after the baseline visit, continuing up to week 104.

at each visit vital signs, laboratory tests, and a 12‑lead ecg are repeated.

the 6‑minute walk test, lung function tests (fvc, fev1), and nt‑probnp blood sample are performed to monitor changes from baseline.

questionnaires (l‑pf domains and eq‑5d‑5l) are completed again to assess symptom evolution.

the study medication is continued at the same dose unless a safety issue requires adjustment.

throughout the study you are asked to report any new or worsening symptoms, hospitalizations, or other health problems.

serious events such as hospitalization for cardiopulmonary reasons, worsening of pulmonary hypertension, need for lung transplantation, or death are recorded and evaluated by the study investigators.

you may remain in the study for the full 104‑week period as long as the medication is tolerated and no safety concerns arise.

the study team may discontinue the medication if severe adverse events occur or if you choose to stop.

at the end of the 104‑week period a comprehensive evaluation identical to the baseline assessments is performed.

data collected include vital signs, laboratory results, ecg, 6‑minute walk distance, lung function, nt‑probnp levels, and questionnaire scores.

after the final visit the study medication is stopped and you receive standard medical follow‑up as appropriate.