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Corboz MR, Plaunt AJ, Malinin VS, Li Z, Gauani H, Chun D, Cipolla D, Perkins WR, Chapman RW. Assessment of Inhaled Treprostinil Palmitil, Inhaled and Intravenous Treprostinil, and Oral Selexipag in a Sugen/Hypoxia Rat Model of Pulmonary Arterial Hypertension. J Pharmacol Exp Ther 2022; 383:103-116. [PMID: 36507843 DOI: 10.1124/jpet.122.001174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 07/12/2022] [Indexed: 12/15/2022] Open
Abstract
Treprostinil palmitil (TP), a long-acting inhaled pulmonary vasodilator prodrug of treprostinil (TRE), has beneficial effects in a Sugen5416/hypoxia (Su/Hx) rat model of pulmonary arterial hypertension (PAH) that compare favorably to the oral phosphodiesterase 5 inhibitor (PDE5) sildenafil. In this study in male Sprague-Dawley rats, a dry powder formulation of TP (TPIP) was compared with inhaled and intravenous TRE and oral selexipag to evaluate inhibition of hemodynamic and pathologic changes in the lungs and heart induced by Su/Hx challenge. Su (20 mg/kg) was injected subcutaneously followed by 3 weeks of Hx (10% O2/balance N2) and then initiation of test article administration over 5 weeks with room air breathing. Hemodynamics and histopathology were measured at the end of the study. Su/Hx challenge approximately doubled the mean pulmonary arterial blood pressure (mPAP) and the Fulton index, decreased cardiac output (CO), doubled the wall thickness and muscularization of the small (10-50 μm) and medium (51-100 μm) sized pulmonary arteries, and increased the percentage of obliterated pulmonary blood vessels. Even though inhaled TRE (65 μg/kg, 4× daily), intravenous TRE (810 ng/kg/min), and oral selexipag (30 mg/kg, twice daily) provided some beneficial effects against the Su/Hx challenge, the overall benefit was generally greater with TPIP at high dose (117 μg/kg, once daily). These results demonstrate that TPIP compares favorably to inhaled and intravenous TRE and oral selexipag with respect to inhibition of the pathophysiological changes induced by Su/Hx challenge in rats. SIGNIFICANCE STATEMENT: Treprostinil palmitil (TP) is a long-acting pulmonary vasodilator prodrug of treprostinil (TRE) formulated for inhaled administration by dry powder [treprostinil palmitil inhalation powder (TPIP)]. Comparison of the activity of TPIP, inhaled and intravenous TRE, and oral selexipag in a Sugen5416/hypoxia (Su/Hx) rat model of pulmonary arterial hypertension demonstrated that each of these drugs exert protection against the hemodynamic and histopathological changes induced by the Su/Hx challenge, with the greatest effect on these changes produced by TPIP.
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Affiliation(s)
| | | | | | - Zhili Li
- Insmed Incorporated, Bridgewater, New Jersey
| | | | - Donald Chun
- Insmed Incorporated, Bridgewater, New Jersey
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Chapman RW, Corboz MR, Malinin VS, Plaunt AJ, Konicek DM, Li Z, Perkins WR. An overview of the biology of a long-acting inhaled treprostinil prodrug. Pulm Pharmacol Ther 2021; 65:102002. [PMID: 33596473 DOI: 10.1016/j.pupt.2021.102002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/01/2021] [Accepted: 02/07/2021] [Indexed: 01/01/2023]
Abstract
Treprostinil (TRE) is a prostanoid analog pulmonary vasodilator drug marketed with subcutaneous, intravenous (i.v.), oral, and inhaled routes of administration for the treatment of pulmonary arterial hypertension (PAH). Due to its short half-life, TRE requires either continuous infusion or multiple dosing, which exacerbates its side effects. Therefore, a long-acting prostanoid analog that maintains the positive attributes of TRE but has fewer TRE-related side effects could be of clinical benefit. In this report, we describe the discovery, preclinical development, and biology of the TRE ester prodrug, treprostinil palmitil (TP), which is formulated in a lipid nanoparticle (LNP) for administration as a nebulized inhaled suspension (TPIS). In screening assays focused on the conversion of prodrug to TRE, TP (16 carbon alkyl chain) had the slowest rate of conversion compared with short-alkyl chain TRE prodrugs (i.e., 2-8 carbon alkyl chain). Furthermore, TP is a pure prodrug and possesses no inherent binding to G-protein coupled receptors including prostanoid receptors. Pharmacokinetic studies in rats and dogs demonstrated that TPIS maintained relatively high concentrations of TP in the lungs yet had a low maximum plasma concentrations (Cmax) of both TP and, more importantly, the active product, TRE. Efficacy studies in rats and dogs demonstrated inhibition of pulmonary vasoconstriction induced by exposure to hypoxic air or i.v.-infused U46619 (thromboxane mimetic) over 24 h with TPIS. Cough was not observed with TPIS at an equivalent dose at which TRE caused cough in guinea pigs and dogs, and there was no evidence of desensitization to the inhibition of pulmonary vasoconstriction in rats with repeat inhaled dosing. TPIS was also more efficacious than i.v.-infused TRE in a sugen/hypoxia rat model of PAH to inhibit pulmonary vascular remodeling, an effect likely driven by local activities of TRE within the lungs. TPIS also demonstrated antifibrotic and anti-inflammatory activity in the lungs in rodent models of pulmonary fibrosis and asthma. In a phase 1 study in healthy human participants, TPIS (referred to as INS1009) had a lower plasma TRE Cmax and fewer respiratory-related side effects at equimolar doses compared with inhaled TRE. We have now formulated TP as an aerosol powder for delivery by a dry powder inhaler (referred to as treprostinil palmitil inhalation powder-TPIP), and as an aerosol solution in a fluorohydrocarbon solvent for delivery by a metered dose inhaler. These options may reduce drug administration time and involve less device maintenance compared with delivery by nebulization.
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Affiliation(s)
| | - Michel R Corboz
- Insmed Incorporated, 202/206 North, Bridgewater, NJ, 08807, USA
| | | | - Adam J Plaunt
- Insmed Incorporated, 202/206 North, Bridgewater, NJ, 08807, USA
| | - Donna M Konicek
- Insmed Incorporated, 202/206 North, Bridgewater, NJ, 08807, USA
| | - Zhili Li
- Insmed Incorporated, 202/206 North, Bridgewater, NJ, 08807, USA
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Plaunt AJ, Islam S, Macaluso T, Gauani H, Baker T, Chun D, Viramontes V, Chang C, Corboz MR, Chapman RW, Li Z, Cipolla DC, Perkins WR, Malinin VS. Development and Characterization of Treprostinil Palmitil Inhalation Aerosol for the Investigational Treatment of Pulmonary Arterial Hypertension. Int J Mol Sci 2021; 22:E548. [PMID: 33430435 PMCID: PMC7828008 DOI: 10.3390/ijms22020548] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/01/2021] [Accepted: 01/02/2021] [Indexed: 12/12/2022] Open
Abstract
Treprostinil palmitil (TP) is a prodrug of treprostinil (TRE), a pulmonary vasodilator that has been previously formulated for inhaled administration via a nebulizer. TP demonstrates a sustained presence in the lungs with reduced systemic exposure and prolonged inhibition of hypoxia-induced pulmonary vasoconstriction in vivo. Here, we report on re-formulation efforts to develop a more convenient solution-based metered-dose inhaler (MDI) formulation of TP, a treprostinil palmitil inhalation aerosol (TPIA) that matches the pharmacokinetic (PK) and efficacy profile of a nebulized TP formulation, treprostinil palmitil inhalation suspension (TPIS). MDI canisters were manufactured using a two-stage filling method. Aerosol performance, formulation solubility, and chemical stability assays were utilized for in vitro evaluation. For in vivo studies, TPIA formulations were delivered to rodents using an inhalation tower modified for MDI delivery. Using an iterative process involving evaluation of formulation performance in vitro (TP and excipient solubility, chemical stability, physical stability, and aerosol properties) and confirmatory testing in vivo (rat PK and efficacy, guinea pig cough), a promising formulation was identified. The optimized formulation, TPIA-W, demonstrates uniform in vitro drug delivery, a PK profile suitable for a once-daily administration, efficacy lasting at least 12 h in a hypoxic challenge model, and a significantly higher cough threshold than the parent drug treprostinil.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Vladimir S. Malinin
- Insmed Incorporated, Bridgewater, NJ 08807, USA; (A.J.P.); (S.I.); (T.M.); (H.G.); (T.B.); (D.C.); (V.V.); (C.C.); (M.R.C.); (R.W.C.); (Z.L.); (D.C.C.); (W.R.P.)
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