Therapeutic administration of inhaled INS1009, a treprostinil prodrug formulation, inhibits bleomycin-induced pulmonary fibrosis in rats

In this study, we evaluated the effect of the inhaled treprostinil prodrug hexadecyl-treprostinil (C16TR) formulated in a lipid nanoparticle (INS1009) administered therapeutically in a fibrotic rat model. Male Fischer 344 rats challenged with intra-tracheal saline instillation were then treated with daily inhaled phosphate buffered saline (PBS) while rats challenged with bleomycin sulfate (3.5–4.0 mg/kg) instillation were treated with either daily inhaled PBS, daily inhaled INS1009 (10, 30, or 100 μg/kg), or twice-daily orally with the anti-fibrotic compound pirfenidone (100 mg/kg). Dosing started on day 10 post-bleomycin challenge and continued until day 27 after bleomycin. Lungs were harvested 24 h after the last dose of treatment for evaluation of lung hydroxyproline content and pulmonary histology. Lung hydroxyproline content increased from 421 μg/lung lobe in saline challenged and PBS treated animals to 673 μg/lung lobe in bleomycin challenged and PBS treated rats. Treatment of bleomycin challenged rats with 10, 30, or 100 μg/kg INS1009 dose-dependently reduced lung hydroxyproline content to 563, 501, and 451 μg/lung lobe, respectively, and pirfenidone decreased hydroxyproline content to 522 μg/lung lobe. Histologically, both INS1009 (100 μg/kg) and pirfenidone (100 mg/kg) reduced the severity of subepithelial fibrosis. Single dose pharmacokinetic (PK) studies of inhaled INS1009 in bleomycin challenged rats showed dose-dependent increases in lung C...
Source: Pulmonary Pharmacology and Therapeutics - Category: Respiratory Medicine Source Type: research