C104-08 A Retrospective Observational Study of the Effects of Inhaled Treprostinil in ILD-PH Patients Over 12 Months

Rationale The 16-week INCREASE trial demonstrated that inhaled Treprostinil improved walk distance in patients with interstitial lung disease-associated pulmonary hypertension (ILD-PH). A secondary post-hoc study suggested inhaled Treprostinil was associated with improvement in FVC in ILD-PH patients. This follow up study has led to the ongoing TETON-IPF and TETON-PPF trials which are investigating inhaled Treprostinil’s effect on FVC in ILD patients without PH. Since inhaled Treprostinil has been in clinical use for ILD-PH since 2021, our study aimed to determine whether real-world data continued to support its potential benefits by retrospectively assessing patients over their first year of treatment. Methods In this retrospective observational cohort study, patients with ILD-PH were identified from a database of individuals receiving treatment for pulmonary hypertension between June 2022 and February 2024. Data were collected at approximately 3, 6-, and 12-month intervals.Inclusion required baseline assessments and at least one follow-up measurement of pulmonary function tests (PFTs), six-minute walk distance (6MWD), right heart catheterization (RHC), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and echocardiography within the study period. Additional data were obtained on concurrent medications (including pulmonary-selective vasodilators, antifibrotic agents, and immunosuppressive therapies), mortality, hospitalizations, and adverse effects attributed to inhaled Treprostinil. Results Of the 120 patients screened from a predetermined PH-Treprostinil database, 59 met inclusion criteria. Approximately 50% were on immunosuppressive therapy, 30% on antifibrotic agents, and 30-40% on additional pulmonary vasodilators during the study period.Compared with baseline, no statistically significant changes were observed in FVC, DLCO, or 6MWD at 3, 6, or 12 months (p < 0.05). Among 34 patients with follow-up echocardiography at 6 or 12 months, 21% demonstrated improved RVSP, while a similar proportion remained >35 mmHg. Systolic or diastolic dysfunction was present in 38% of these patients.Repeat RHC showed a nonsignificant trend toward lower mPAP and reduced NT-proBNP, with no change in cardiac index. Over the study period, there were 34 hospitalizations and one death. Conclusions No statistically significant changes were observed in FVC, DLCO, 6MWD, NT-proBNP, mPAP, or cardiac index following inhaled Treprostinil therapy in ILD-PH patients. Study limitations included small sample size, inconsistent data collection, and difficulty tracking dose adjustments. These results emphasize the value of randomized controlled trials such as INCREASE and TETON-IPF while illustrating the challenges of real-world data collection. Comorbidities, concurrent therapies, and overall disease burden may have attenuated the observed treatment effect. This abstract is funded by: None