Early Experience with Inhaled Treprostinil in Patients with Pulmonary Hypertension Associated with Interstitial Lung Disease Awaiting Lung Transplantation: A Single-Center Case Series

Background: Pulmonary hypertension (PH) is a poor prognostic factor in patients with interstitial lung disease (ILD). While conventional therapies for PH are non-selective and may worsen ventilation–perfusion mismatch, inhaled treprostinil (iTre) selectively targets ventilated lung regions. Following its approval for PH-ILD in Japan in 2024, the number of lung transplantation (LTx) candidates receiving iTre has increased. We report our early experience with iTre in patients with PH-ILD awaiting LTx.

Case Description: We retrospectively reviewed deceased-donor lung transplantation from July 2024 to July 2025 to assess iTre as a supportive therapy to LTx. Data collected included ILD subtype and modified Medical Research Council (mMRC) scale. Among 46 recipients, 37 had interstitial pneumonia and 11 had PH-ILD; 6 PH-ILD (4 males, 2 females; median age 52.5 years, range: 42–61) patients received iTre before LTx. The cohort included 3 patients with idiopathic interstitial pneumonias and 3 with connective tissue disease-associated ILD. The median waitlist duration was 684 days (range: 354–1070). iTre was initiated at 3 breaths per session (bps) four times daily via nebulizer and titrated to a final dose of 6–12 bps over a median treatment duration of 140.5 days (range: 14–410). The modified Medical Research Council (mMRC) score was 4 (median, range: 3–4) at iTre initiation and 3 (median, range: 3–4) at LTx, with 2 patients improving by one grade and 4 remaining stable. Four patients who achieved ≥8 bps were weaned from central extracorporeal membrane oxygenation (ECMO) intraoperatively. One patient, whose dose was limited to 6 bps due to coughing and dyspnea, required ECMO continuation until postoperative day 6. All 6 patients were successfully discharged.

Conclusions: This case series suggests iTre may help maintain clinical stability in patients with PH-ILD awaiting LTx.