TOPIC: Pulmonary Vascular Disease TYPE: Original Investigations PURPOSE: Inhaled treprostinil (i-TRE) has been shown in large scale clinical trials to improve exercise capacity and quality of life in patients with pulmonary arterial hypertension. However, real-world evidence is limited for initial i-TRE and particularly in patients on prior dual background PAH therapy with an endothelin receptor antagonist (ERA) and phosphodiesterase-5 inhibitor (PDE5i) or soluble guanylate cyclase (SGC). METHODS: A retrospective cohort study of patients initiating i-TRE was conducted using the Optum® De-identified Clinformatics® Data Mart. Patients were identified having a pharmacy or medical claim for i-TRE between 01-JAN-2011 through 30-SEP-2019 and indexed on date of first claim. Patients were required to be ≥18 years of age at index, have ≥1 inpatient or ≥2 outpatient medical claims separated by at least 30 days with a diagnosis of pulmonary hypertension (International Classification of Diseases, 9th/10th Edition, Clinical Modification: 416.0, 416.8, 416.9, I27.0, I27.2, I27.20, I27.21, I27.81, I27.89, I27.9) in the 12-months pre-index, continuous enrollment from the 12-months pre-index through 12-months post-index, and no claim for i-TRE in the pre-index. Dual background therapy was classified as having an ERA and PDE5i or SGC in the 3-months prior to index. Outcomes were compared in the pre-index period to the post-index period. Continuous variables were compared using Wilcoxon signed rank sum test and dichotomous variables were compared using McNemar’s test. RESULTS: 332 patients initiating i-TRE met full selection criteria and a subgroup of 76 were categorized as having dual background therapy. Baseline characteristics were fairly similar with a mean (standard deviation[SD]) age at index of 65.1(13.0) and 60.9(14.6), percent female 65.7% and 64.5%, and mean(SD) Quan-Charlson Comorbidity Index of 3.44(1.8) and 3.43(1.8) for all initiators and dual background therapy patients, respectively. The percent of all initiators experiencing an all-cause hospitalization significantly decreased from 170 (51.2%) in the pre-index to 130 (39.2%) in the post-index period (p=0.0007). A larger significant decrease in hospitalizations was seen in dual background therapy initiators with 40 (52.6%) experiencing any hospitalization in the pre-index versus 23 (30.3%) in the post-index (p=0.0011). For all initiators and dual background therapy, no changes were observed for utilization of emergency department visits, physician office visits, or other outpatient visits. CONCLUSIONS: In this analysis of real-world data, inhaled treprostinil was effective in reducing hospitalization, a known risk factor for poor outcomes. The benefit remained substantial even in patients on prior dual background therapy with an ERA and PDE5i or SGC. CLINICAL IMPLICATIONS: This claims analysis suggest the use of inhaled treprostinil is an effective treatment modality to reduce hospitalizations for pulmonary hypertension. DISCLOSURES: No relevant relationships by Charles Burger, source=Web Response Employee relationship with United Therapeutics Please note: >$100000 by Peter Classi, source=Web Response, value=Salary Employee relationship with United Therapeutics Please note: >$100000 by Andrew Nelsen, source=Web Response, value=Salary Employee relationship with United Therapeutics Please note: 07/2019 - present Added 04/20/2021 by Christine Park, source=Web Response, value=Salary Employee relationship with United Therapeutics Corporation Please note: Present Added 04/01/2021 by Benjamin Wu, source=Web Response, value=Salary