Inhaled treprostinil: a therapeutic review

Updates on Pulmonary Hypertension

Pulmonary Arterial Hypertension (PAH) is an uncommon condition with high mortality. It is an underrecognized condition both in developing and developed countries, especially in developing countries, due to a lack of advanced healthcare facilities and resources for timely diagnosis. More than half of the individuals diagnosed with PAH live less than five years after diagnosis. In recent years, tremendous advancements have been made in diagnostic and therapeutic strategies for PAH patients. Phosphodiesterase 5 (PDE5) inhibitors, endothelin receptor antagonists, and prostacyclin inhibitors in various forms (oral, inhaled, intravenous, or subcutaneous) have been the cornerstone of medical treatment. Atrial septostomy, heart and lung transplant, balloon pulmonary angioplasty, and pulmonary thromboendarterectomy are existing therapeutic options currently available. There has been a continuous effort to introduce newer therapies to improve life expectancy and modify disease. Newer therapies have shown promising results but require future data to guarantee long-term safety and efficacy. We aim to discuss a few of these critical updates in the constantly evolving field of PAH.

Advances in the potential of nebulized inhalation for the treatment of pulmonary arterial hypertension

Pulmonary hypertension is a pathophysiologic manifestation of a heterogeneous group of diseases, with the main pathophysiologic mechanisms being persistent pulmonary vasoconstriction and irreversible vascular remodeling. The impact significantly affects the prognosis of patients with pulmonary hypertension. If it is not treated and intervened in time, it may lead to right ventricular failure and further endanger the patient's life. Within the past decade or so, nebulized inhalation therapy is considered to have advantages in the treatment of pulmonary hypertension as a safe, limited, and rapid therapy, for example, inhaled vasodilators (prostate analogs, nitroglycerin, carbon monoxide analogs sildenafil, and nitroprusside), inhaled anti-inflammatory and antiproliferative agents (simvastatin, and selatinib), and inhaled peroxides (levocetirizine) have been recognized as emerging therapeutic approaches in the treatment of pulmonary hypertension as emerging therapeutic approaches. Therefore, this article provides a brief review of recent advances in the potential of nebulized inhaled vasodilators, anti-inflammatory and antiproliferative agents, and anti-peroxides for the treatment of pulmonary hypertension, with the aim of providing different therapeutic options for the treatment of pulmonary hypertension, enhancing the quality of survival, alleviating symptoms, and improving the prognosis of patients with this condition.

Vasoactive drugs for the treatment of pulmonary hypertension associated with interstitial lung diseases: a systematic review

OBJECTIVES

Vasoactive drugs have exhibited clinical efficacy in addressing pulmonary arterial hypertension, manifesting a significant reduction in morbidity and mortality. Pulmonary hypertension may complicate advanced interstitial lung disease (PH-ILD) and is associated with high rates of disability, hospitalisation due to cardiac and respiratory illnesses, and mortality. Prior management hinged on treating the underlying lung disease and comorbidities. However, the INCREASE trial of inhaled treprostinil in PH-ILD has demonstrated that PH-ILD can be effectively treated with vasoactive drugs.

METHODS

This comprehensive systematic review examines the evidence for vasoactive drugs in the management of PH-ILD.

RESULTS

A total of 1442 pubblications were screened, 11 RCTs were considered for quantitative synthesis. Unfortunately, the salient studies are limited by population heterogeneity, short-term follow-up and the selection of outcomes with uncertain clinical significance.

CONCLUSIONS

This systematic review underscores the necessity of establishing a precision medicine-oriented strategy, directed at uncovering and addressing the intricate cellular and molecular mechanisms that underlie the pathophysiology of PH-ILD.

PROSPERO REGISTRATION NUMBER

CRD42023457482.

Inhaled nintentanib, pirfenidone and macitentan for pulmonary fibrosis: a laboratory experiment

Aim: Idiopathic pulmonary fibrosis is a rare disease with few efficient drugs in the market. The consequences of this disease are mainly respiratory failure and pulmonary hypertension. Materials & methods: In our experiment we used the drugs pirfenidone, nintetanib and macitentan. We performed nebulization experiments with three jet nebulizers and three ultrasound nebulizers with different combinations of residual cup designs, and residual cup loadings in order to identify which combination produces droplets of less than 5 μm in mass median aerodynamic diameter. Results: Pirfenidone versus nintetanib had smaller droplet size formation at both inhaled technologies (1.37 < 2.23 and 1.92 < 3.11, jet and ultrasound respectively). Discussion: Pirfenidone and nintetanib can be administered as aerosol in any type of nebulization system.

Pulmonary hypertension inhaled therapies: An updated review

Treatments of pulmonary hypertension (PH) continue to evolve with approval of new therapies. The currently FDA approved inhaled PH therapies include inhaled iloprost for group 1 pulmonary arterial hypertension (PAH), inhaled treprostinil solution and treprostinil dry powder inhaler for both group 1 PAH and group 3 PH associated with interstitial lung disease (PH-ILD). Inhaled treprostinil was recently approved for group 3 PH-ILD based on the results of INCREASE trial and the newer formulation of treprostinil dry powder that comes with a new inhaler was recently approved for both group 1 PAH and group 3 PH-ILD based on BREEZE study. The pipeline for inhaled PH therapies includes several promising molecules that can enrich the current PH therapeutic era and mitigate several systemic side effects by directly delivering the drug to the target organ. In this review article we summarize the evidence for the currently approved inhaled PAH/PH therapies, discuss the available inhalation devices, present a roadmap for successful treatment strategy, and present several inhaled PAH/PH therapies in the pipeline.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

An Update on Advancements and Challenges in Inhalational Drug Delivery for Pulmonary Arterial Hypertension

A lethal condition at the arterial–alveolar juncture caused the exhaustive remodeling of pulmonary arterioles and persistent vasoconstriction, followed by a cumulative augmentation of resistance at the pulmonary vascular and, consequently, right-heart collapse. The selective dilation of the pulmonary endothelium and remodeled vasculature can be achieved by using targeted drug delivery in PAH. Although 12 therapeutics were approved by the FDA for PAH, because of traditional non-specific targeting, they suffered from inconsistent drug release. Despite available inhalation delivery platforms, drug particle deposition into the microenvironment of the pulmonary vasculature and the consequent efficacy of molecules are influenced by pathophysiological conditions, the characteristics of aerosolized mist, and formulations. Uncertainty exists in peripheral hemodynamics outside the pulmonary vasculature and extra-pulmonary side effects, which may be further exacerbated by underlying disease states. The speedy improvement of arterial pressure is possible via the inhalation route because it has direct access to pulmonary arterioles. Additionally, closed particle deposition and accumulation in diseased tissues benefit the restoration of remolded arterioles by reducing fallacious drug deposition in other organs. This review is designed to decipher the pathological changes that should be taken into account when targeting the underlying pulmonary endothelial vasculature, especially with regard to inhaled particle deposition in the alveolar vasculature and characteristic formulations.

BREEZE: Open-label clinical study to evaluate the safety and tolerability of treprostinil inhalation powder as Tyvaso DPI™ in patients with pulmonary arterial hypertension

Inhaled treprostinil is an approved therapy for pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease in the United States. Studies have confirmed the robust benefits and safety of nebulized inhaled treprostinil, but it requires a time investment for nebulizer preparation, maintenance, and treatment. A small, portable treprostinil dry powder inhaler has been developed for the treatment of PAH. The primary objective of this study was to evaluate the safety and tolerability of treprostinil inhalation powder (TreT) in patients currently treated with treprostinil inhalation solution. Fifty-one patients on a stable dose of treprostinil inhalation solution enrolled and transitioned to TreT at a corresponding dose. Six-minute walk distance (6MWD), device preference and satisfaction (Preference Questionnaire for Inhaled Treprostinil Devices [PQ-ITD]), PAH Symptoms and Impact (PAH-SYMPACT®) questionnaire, and systemic exposure and pharmacokinetics for up to 5 h were assessed at baseline for treprostinil inhalation solution and at Week 3 for TreT. Adverse events (AEs) were consistent with studies of inhaled treprostinil in patients with PAH, and there were no study drug-related serious AEs. Statistically significant improvements occurred in 6MWD, PQ-ITD, and PAH-SYMPACT. Forty-nine patients completed the 3-week treatment phase and all elected to participate in an optional extension phase. These results demonstrate that, in patients with PAH, transition from treprostinil inhalation solution to TreT is safe, well-tolerated, and accompanied by statistically significant improvements in key clinical assessments and patient-reported outcomes with comparable systemic exposure between the two formulations at evaluated doses (trial registration: clinicaltrials.gov identifier: NCT03950739).

Strategies to Overcome Biological Barriers Associated with Pulmonary Drug Delivery

While the inhalation route has been used for millennia for pharmacologic effect, the biological barriers to treating lung disease created real challenges for the pharmaceutical industry until sophisticated device and formulation technologies emerged over the past fifty years. There are now several inhaled device technologies that enable delivery of therapeutics at high efficiency to the lung and avoid excessive deposition in the oropharyngeal region. Chemistry and formulation technologies have also emerged to prolong retention of drug at the active site by overcoming degradation and clearance mechanisms, or by reducing the rate of systemic absorption. These technologies have also been utilized to improve tolerability or to facilitate uptake within cells when there are intracellular targets. This paper describes the biological barriers and provides recent examples utilizing formulation technologies or drug chemistry modifications to overcome those barriers.

Inhaled Medicines: Past, Present, and Future

The purpose of this review is to summarize essential pharmacological, pharmaceutical, and clinical aspects in the field of orally inhaled therapies that may help scientists seeking to develop new products. After general comments on the rationale for inhaled therapies for respiratory disease, the focus is on products approved approximately over the last half a century. The organization of these sections reflects the key pharmacological categories. Products for asthma and chronic obstructive pulmonary disease include β -2 receptor agonists, muscarinic acetylcholine receptor antagonists, glucocorticosteroids, and cromones as well as their combinations. The antiviral and antibacterial inhaled products to treat respiratory tract infections are then presented. Two "mucoactive" products-dornase α and mannitol, which are both approved for patients with cystic fibrosis-are reviewed. These are followed by sections on inhaled prostacyclins for pulmonary arterial hypertension and the challenging field of aerosol surfactant inhalation delivery, especially for prematurely born infants on ventilation support. The approved products for systemic delivery via the lungs for diseases of the central nervous system and insulin for diabetes are also discussed. New technologies for drug delivery by inhalation are analyzed, with the emphasis on those that would likely yield significant improvements over the technologies in current use or would expand the range of drugs and diseases treatable by this route of administration. SIGNIFICANCE STATEMENT: This review of the key aspects of approved orally inhaled drug products for a variety of respiratory diseases and for systemic administration should be helpful in making judicious decisions about the development of new or improved inhaled drugs. These aspects include the choices of the active ingredients, formulations, delivery systems suitable for the target patient populations, and, to some extent, meaningful safety and efficacy endpoints in clinical trials.

Safety, Tolerability, and Pharmacokinetics of Treprostinil Palmitil Inhalation Powder for Pulmonary Hypertension: A Phase 1, Randomized, Double-Blind, Single- and Multiple-Dose Study

INTRODUCTION

Treprostinil is a prostacyclin vasodilator widely used for the treatment of pulmonary arterial hypertension (PAH) and, in its inhaled form, for pulmonary hypertension associated with interstitial lung disease (PH-ILD). Treprostinil palmitil inhalation powder (TPIP) is a dry powder formulation of treprostinil palmitil (TP), an ester prodrug of treprostinil. TPIP is designed to provide sustained release of treprostinil in the lung over a prolonged period, potentially enabling a once-daily (QD) dosing regimen and significantly higher tolerated doses compared with currently available treprostinil formulations. This phase 1 study assessed the safety, tolerability, and pharmacokinetics of TP and treprostinil following single and multiple QD administrations of TPIP in healthy volunteers.

METHODS

Healthy adults (aged 18-45 years) were randomized to receive single or multiple QD inhalation doses of TPIP. Participants in the single-dose phase received TPIP 112.5, 225, 450, or 675 µg (n = 6/dose) or placebo (n = 2). Participants in the multiple-dose phase received TPIP 225 µg QD for 7 days (n = 6), 112.5 µg QD for 4 days followed by 225 µg QD for 3 days (n = 6), or placebo for 7 days (n = 4).

RESULTS

Overall, 41 of 42 participants (97.6%) completed the study. In the single-dose phase, 70.8% (n = 17/24) of TPIP-treated participants experienced a treatment-emergent adverse event (TEAE) vs 0% (n = 0/2) of placebo-treated participants; the most common TEAEs (≥ 20%) were cough (45.8%), dizziness (29.2%), and throat irritation (20.8%). In the multiple-dose phase, 83.3% (n = 10/12) of TPIP-treated participants experienced a TEAE vs 50.0% of placebo-treated participants (n = 2/4); the most common TEAEs were cough (58.3% TPIP vs 50.0% placebo), headache (50.0% vs 0%), nausea (33.3% vs 0%), chest discomfort (33.3% vs 0%), and dizziness (25.0% vs 0%). Most TEAEs were mild; only seven patients experienced a moderate TEAE, and no severe or serious TEAEs occurred. In the multiple-dose phase, participants whose doses were titrated from TPIP 112.5 µg QD to 225 µg QD experienced fewer TEAEs than those who received 225 µg QD at treatment initiation (66.7% vs 100.0%), and all TEAEs with dose titration were mild. After a single dose of TPIP, treprostinil elimination t_1/2 was 8.67-11.6 h and exposure was dose proportional, with mean (CV%) C_max 78.4-717 pg/mL (38.6-72.9%) and AUC_0-∞ 1090-5480 pg·h/mL (11.5-30.0%). At steady state (TPIP 225 µg), the mean (CV%) of C_max, C_min, and AUC_τ were 193-228 pg/mL (32.9-46.4%), 17.6-22.8 ng/mL (43.7-64.4%), and 1680-1820 pg·h/mL (28.7-36.6%), respectively. The elimination t_1/2 was 6.84-8.82 h after repeat dosing. No steady-state accumulation was observed. Plasma concentrations of TP were below the limit of quantification (100 pg/mL) at all time points measured.

CONCLUSION

TPIP was well tolerated at the doses tested, and dose titration improved tolerability. Treprostinil pharmacokinetics were linear and supportive of a QD treatment regimen. These results support further development of TPIP in patients with PAH and PH-ILD.

A multicenter retrospective study of patients with pulmonary hypertension transitioned from inhaled to oral treprostinil

Oral treprostinil has recently been shown to delay disease progression in patients with pulmonary arterial hypertension in a long-term outcomes study. The potential advantages of an oral formulation have resulted in patients transitioning from inhaled to oral treprostinil. The current study reports a retrospective analysis of patients who transitioned from treatment with inhaled to oral treprostinil. A multicenter retrospective chart review was conducted for 29 patients with pulmonary hypertension that transitioned from inhaled to oral treprostinil. Data were collected from inhaled treprostinil initiation and patients were followed until discontinuation of oral treprostinil or the end of the observation period. Persistence was calculated using Kaplan–Meier estimates. Prior to transition to oral treprostinil, patients had received inhaled treprostinil for a median of 643 (IQR: 322–991) days and 52% of patients were New York Heart Association/World Health Organization Functional Class III. For patients that cross-titrated between formulations, the median time to complete the cross titration was 24 (IQR: 1–57) days. At 16- and 24-weeks post-transition, oral treprostinil persistence was 86 and 76%, respectively. Persistence was 59% at 52 weeks post-transition. Clinical stability for the majority of patients at first follow-up post-transition was suggested based on available New York Heart Association/World Health Organization Functional Classification. Transitions from inhaled to oral treprostinil appeared safe and tolerable in the short-term. Additional prospective studies are needed to fully evaluate the safety and efficacy of transitions from inhaled to oral treprostinil.

Characterisation of cough evoked by inhaled treprostinil and treprostinil palmitil

Cough is induced by inhaled prostacyclin analogues including treprostinil (TRE), and, at higher doses, treprostinil palmitil (TP), a prodrug of TRE. In this report, we have investigated mechanisms involved in TRE- and TP-induced cough, using a dry powder formulation of TP (TPIP) to supplement previous data obtained with an aqueous suspension formulation of TP (TPIS).

Experiments in guinea pigs and rats investigated the prostanoid receptor subtype producing cough and whether it involved activation of sensory nerves in the airways and vasculature. Experiments involved treatment with prostanoid, tachykinin and bradykinin receptor antagonists, a cyclooxygenase inhibitor and TRE administration to the isolated larynx or intravenously.

In guinea pigs, cough with inhaled TRE (1.23 µg·kg⁻¹) was not observed with an equivalent dose of TPIP and required higher inhaled doses (12.8 and 35.8 µg·kg⁻¹) to induce cough. TRE cough was blocked with IP and tachykinin NK₁ receptor antagonists but not with EP₁, EP₂, EP₃, DP₁ or bradykinin B₂ antagonists or a cyclooxygenase inhibitor. TRE administered to the isolated larynx or intravenously in rats produced no apnoea or swallowing, whereas citric acid, capsaicin and hypertonic saline had significant effects.

The mechanisms inducing cough with inhaled TRE likely involves the activation of prostanoid IP receptors on jugular C-fibres in the tracheobronchial airways. Cough induced by inhaled dry powder and nebulised formulations of TP occurs at higher inhaled doses than TRE, presumably due to the slow, sustained release of TRE from the prodrug resulting in lower concentrations of TRE at the airway sensory nerves.

Cough induced by inhaled treprostinil and treprostinil palmitil involves the activation of prostacyclin (IP) receptors located on airway tachykinin nerveshttps://bit.ly/37sXz1I

An overview of the biology of a long-acting inhaled treprostinil prodrug

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 (C_max) 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 C_max 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.

Comparative bioavailability of inhaled treprostinil administered as LIQ861 and Tyvaso® in healthy subjects

INTRODUCTION

Treprostinil is a synthetic prostacyclin analogue approved for inhalation administration to patients with pulmonary arterial hypertension (PAH) via nebulized Tyvaso® inhalation solution. LIQ861 is an inhaled, dry-powder formulation of treprostinil produced using Print® (Particle Replication in Nonwetting Templates) technology, a proprietary process for designing and producing highly uniform drug particles.

METHODS

We conducted comparative bioavailability analyses of treprostinil exposure from LIQ861 (79.5 μg capsule [approximate delivered dose of 58.1 μg treprostinil]) compared with Tyvaso® (9 breaths [approximate delivered dose of 54 μg treprostinil]).

RESULTS

Treprostinil exposure parameters had least squares geometric mean ratios (LIQ861: Tyvaso®) between 0.9 and 1.0 with 90% confidence intervals contained within 0.8 to 1.25. LIQ861 and Tyvaso® were both well tolerated.

DISCUSSION

Results showed comparable bioavailability of treprostinil and similar tolerability for LIQ861 and Tyvaso® administered to healthy adults.

CONCLUSIONS

Given the comparable treprostinil bioavailability and similar safety profiles of LIQ861 and Tyvaso®, LIQ861 fulfills a significant unmet need for PAH patients by maximizing the therapeutic benefits of treprostinil by safely delivering doses to the lungs in 1 to 2 breaths using a discreet, convenient, easy-to-use inhaler.

Pharmacokinetics and tolerability of LIQ861, a novel dry-powder formulation of treprostinil

A dry-powder inhaled formulation of treprostinil (LIQ861) produced using PRINT® technology offers a substantial advantage over current nebulized therapy. Treprostinil is a synthetic prostacyclin analogue that is currently approved for inhalation administration to patients with pulmonary arterial hypertension via nebulized Tyvaso® inhalation solution. LTI-101 was a phase 1, placebo-controlled, double-blind, randomized, single-center study that evaluated the ascending single-dose pharmacokinetics of LIQ861 in healthy subjects. Six sequential, escalating doses (25, 50, 75, 100, 125, and 150 mcg) were studied to investigate treprostinil exposure from LIQ861 inhalation. Subjects (n = 57) were randomly assigned in a 3:1 ratio to receive a single dose of either LIQ861 (n = 43) or placebo (n = 14); 56 subjects completed all protocol-defined assessments. Following single-dose administration, treprostinil exposure from LIQ861 increased proportionally across the dose range studied, and the pharmacokinetics profile of treprostinil administered as LIQ861 was similar to prior reports of inhaled treprostinil. All doses of LIQ861 were generally well-tolerated with no deaths, serious adverse events, or dose-limiting toxicities. The most frequently reported treatment-emergent adverse events related to study drug administration were coughing and throat irritation, which are common to dry-powder formulations. Treatment-related treatment-emergent adverse events were reported more frequently at higher dose levels; however, all were assessed as mild in severity. We conclude that the pharmacokinetics profile of treprostinil using a dry-powder inhaled formulation increased in proportion to dose as anticipated and was similar to earlier reports of inhaled, nebulized treprostinil (Tyvaso®). Based on these results, a phase 3 study (INSPIRE; Clinicaltrials.gov Identifier NCT03399604) evaluating the long-term safety and tolerability of LIQ861 in patients with pulmonary arterial hypertension was initiated.

Pulmonary Hypertension in an Oncologic Intensive Care Unit

Pulmonary hypertension (PH) is the condition of elevated pressures in the pulmonary circulation. PH can develop acutely in patients with critical illness such as acute respiratory distress syndrome, sepsis, massive pulmonary embolism, left ventricular dysfunction, or after surgery. In a cancer patient, unique etiologies such as myeloproliferative disorders, tyrosine kinase inhibitors, or tumor emboli may result in PH. Early recognition and treatment of the causative condition may reverse acute PH or return chronic PH to its baseline status. Progression of the disease or its decompensation due to infection, a thromboembolic event, or other triggers can lead to admission to an intensive care unit. Regardless of etiology, the development or worsening of PH may precipitate hypoxemia, hemodynamic instability, or right ventricular failure, which can be challenging to manage or even fatal. In select cases, rapid institution of advanced treatment modalities may be warranted. This chapter reviews the etiology, epidemiology, pathophysiology, clinical features, diagnosis, and prognosis of PH and presents a comprehensive analysis of PH and right heart failure management strategies in the critical care setting. In particular, a unique perspective on oncologically relevant PH is provided.

Future of nanomedicines for treating respiratory diseases

INTRODUCTION

Nanoparticles are under discussion in drug delivery for more than 20 years now, but examples for nanoparticulate formulations in the treatment of respiratory diseases are rare and mostly limited to the administration of sub-micron drug particles (ultrafine particles). However, nanoparticles may also carry specific benefits for respiratory treatment. Are nanoparticles the next-generation drug carrier system to facilitate systemic delivery, sustained release and cancer treatment in the lungs?

AREAS COVERED

This review will look into the promises and opportunities of the use of nanoparticles in the treatment of respiratory diseases. Important aspects to discuss are the fate of nanoparticles in the lung and mechanisms for reproducible delivery of nanoparticulate formulations to the lungs. Examples are given where nanoparticles may be advantageous over for traditional formulations and further aspects to explore are mentioned.

EXPERT OPINION

The benefit of nanoparticulate systems for respiratory delivery adds to the portfolio of possible formulation strategies, depends on the intended functionality and needs more exploration. Advantages of such systems are only seen in special cases.

Evaluation and Management of Right-Sided Heart Failure: A Scientific Statement From the American Heart Association

Background and Purpose:

The diverse causes of right-sided heart failure (RHF) include, among others, primary cardiomyopathies with right ventricular (RV) involvement, RV ischemia and infarction, volume loading caused by cardiac lesions associated with congenital heart disease and valvular pathologies, and pressure loading resulting from pulmonic stenosis or pulmonary hypertension from a variety of causes, including left-sided heart disease. Progressive RV dysfunction in these disease states is associated with increased morbidity and mortality. The purpose of this scientific statement is to provide guidance on the assessment and management of RHF.

Methods:

The writing group used systematic literature reviews, published translational and clinical studies, clinical practice guidelines, and expert opinion/statements to summarize existing evidence and to identify areas of inadequacy requiring future research. The panel reviewed the most relevant adult medical literature excluding routine laboratory tests using MEDLINE, EMBASE, and Web of Science through September 2017. The document is organized and classified according to the American Heart Association to provide specific suggestions, considerations, or reference to contemporary clinical practice recommendations.

Results:

Chronic RHF is associated with decreased exercise tolerance, poor functional capacity, decreased cardiac output and progressive end-organ damage (caused by a combination of end-organ venous congestion and underperfusion), and cachexia resulting from poor absorption of nutrients, as well as a systemic proinflammatory state. It is the principal cause of death in patients with pulmonary arterial hypertension. Similarly, acute RHF is associated with hemodynamic instability and is the primary cause of death in patients presenting with massive pulmonary embolism, RV myocardial infarction, and postcardiotomy shock associated with cardiac surgery. Functional assessment of the right side of the heart can be hindered by its complex geometry. Multiple hemodynamic and biochemical markers are associated with worsening RHF and can serve to guide clinical assessment and therapeutic decision making. Pharmacological and mechanical interventions targeting isolated acute and chronic RHF have not been well investigated. Specific therapies promoting stabilization and recovery of RV function are lacking.

Conclusions:

RHF is a complex syndrome including diverse causes, pathways, and pathological processes. In this scientific statement, we review the causes and epidemiology of RV dysfunction and the pathophysiology of acute and chronic RHF and provide guidance for the management of the associated conditions leading to and caused by RHF.

Transitioning Parenteral or Inhaled Treprostinil to Oral Treprostinil Diolamine: Case Series and Review of the Literature

Treprostinil diolamine is the first oral dosage preparation of a prostacyclin analogue for use in treatment naive pulmonary arterial hypertension (PAH). This case series and review of the available literature describes the experience of patients with PAH receiving treprostinil by intravenous (IV), subcutaneous (SQ), or inhalation route who were transitioned to treprostinil diolamine. At our institution, 3 patients were transitioned to treprostinil diolamine who received treprostinil administered by each of the alternative routes: IV, SQ, and inhalation. All patients tolerated the transition without significant worsening of disease end points. In the literature, 5 additional reports representing 48 patients were transitioned to treprostinil diolamine from an alternate route of administration. A majority (92%) of patients were hospitalized during the cross-titration phase and tolerated the transition without changes in disease markers or significant adverse effect. Six (13%) patients required reinitiation of parenteral therapy due to clinical decline. The most common dosing frequency utilized for treprostinil diolamine was 3 times per day. In patients with stable PAH receiving parenteral or inhaled treprostinil, a transition to treprostinil diolamine was a safe approach in a highly select population meeting clinical end points. Additional studies are required to further describe this clinical strategy before accepted in clinical practice.

Preclinical Pharmacology and Pharmacokinetics of Inhaled Hexadecyl-Treprostinil (C16TR), a Pulmonary Vasodilator Prodrug

This article describes the preclinical pharmacology and pharmacokinetics (PK) of hexadecyl-treprostinil (C16TR), a prodrug of treprostinil (TRE), formulated in a lipid nanoparticle (LNP) for inhalation as a pulmonary vasodilator. C16TR showed no activity (>10 µM) in receptor binding and enzyme inhibition assays, including binding to prostaglandin E2 receptor 2, prostaglandin D2 receptor 1, prostaglandin I2 receptor, and prostaglandin E2 receptor 4; TRE potently bound to each of these prostanoid receptors. C16TR had no effect (up to 200 nM) on platelet aggregation induced by ADP in rat blood. In hypoxia-challenged rats, inhaled C16TR-LNP produced dose-dependent (0.06-6 µg/kg), sustained pulmonary vasodilation over 3 hours; inhaled TRE (6 µg/kg) was active at earlier times but lost its effect by 3 hours. Single- and multiple-dose PK studies of inhaled C16TR-LNP in rats showed proportionate dose-dependent increases in TRE Cmax and area under the curve (AUC) for both plasma and lung; similar results were observed for dog plasma levels in single-dose PK studies. In both species, inhaled C16TR-LNP yielded prolonged plasma TRE levels and a lower plasma TRE Cmax compared with inhaled TRE. Inhaled C16TR-LNP was well tolerated in rats and dogs; TRE-related side effects included cough, respiratory tract irritation, and emesis and were seen only after high inhaled doses of C16TR-LNP in dogs. In guinea pigs, inhaled TRE (30 µg/ml) consistently produced cough, but C16TR-LNP (30 µg/ml) elicited no effect. These results demonstrate that C16TR-LNP provides long-acting pulmonary vasodilation, is well tolerated in animal studies, and may necessitate less frequent dosing than inhaled TRE with possibly fewer side effects.

Effect of gemfibrozil and rifampicin on the pharmacokinetics of selexipag and its active metabolite in healthy subjects

AIMS

Based on in vitro data, there is evidence to suggest that cytochrome P450 (CYP) 2C8 is involved in the metabolism of selexipag and its active metabolite, ACT-333679. The present study evaluated the possible pharmacokinetic interactions of selexipag with gemfibrozil, a strong CYP2C8 inhibitor, and rifampicin, an inducer of CYP2C8.

METHODS

The study consisted of two independent parts, each conducted according to an open-label, randomized, crossover design. The pharmacokinetics and safety of selexipag and ACT-333679 were studied following single-dose administration either alone or in the presence of multiple-dose gemfibrozil (part I) or rifampicin (part II) in healthy male subjects.

RESULTS

Gemfibrozil had comparatively small effects on selexipag (less than 2-fold difference in any pharmacokinetic variable) but, with respect to ACT-333679, increased the maximum plasma concentration (C_max ) 3.6-fold [90% confidence interval (CI) 3.1, 4.3] and the area under the plasma concentration-time curve from zero to infinity (AUC_0-∞ ) 11.1-fold (90% CI 9.2, 13.4). The marked increased exposure to ACT-333679, which mediates the majority of the pharmacological activity of selexipag, was accompanied by significantly more adverse events such as headache, nausea and vomiting. Coadministration of rifampicin increased the C_max of selexipag 1.8-fold (90% CI 1.4, 2.2) and its AUC0_-∞ 1.3-fold (90% CI 1.1, 1.4); its effects on ACT-333679 were to increase its C_max 1.3-fold (90% CI 1.1, 1.6), shorten its half-life by 63% and reduce its AUC0_-∞ by half (90% CI 0.45, 0.59).

CONCLUSION

Concomitant administration of selexipag and strong inhibitors of CYP2C8 must be avoided, whereas when coadministered with inducers of CYP2C8, dose adjustments of selexipag should be envisaged.

Inhaled Treprostinil Drug Delivery During Mechanical Ventilation and Spontaneous Breathing Using Two Different Nebulizers

OBJECTIVES

To determine the feasibility of delivering inhaled treprostinil during mechanical ventilation and spontaneous unassisted ventilation using the Tyvaso Inhalation System and the vibrating mesh nebulizer. We sought to compare differences in fine particle fraction, and absolute inhaled treprostinil mass delivered to neonatal, pediatric, and adult models affixed with a face mask, conventional, and high-frequency ventilation between Tyvaso Inhalation System and with different nebulizer locations between Tyvaso Inhalation System and vibrating mesh nebulizer.

DESIGN

Fine particle fraction was first determined via impaction with both the Tyvaso Inhalation System and vibrating mesh nebulizer. Next, a test lung configured with neonatal, pediatric, and adult mechanics and a filter to capture medication was attached to a realistic face model during spontaneous breathing or an endotracheal tube during conventional ventilation and high-frequency oscillator ventilator. Inhaled treprostinil was then nebulized with both the Tyvaso Inhalation System and vibrating mesh nebulizer, and the filter was analyzed via high-performance liquid chromatography. Testing was done in triplicate. Independent two-sample t tests were used to compare mean fine particle fraction and inhaled mass between devices. Analysis of variance with Tukey post hoc tests were used to compare within device differences.

SETTING

Academic children's hospital aerosol research laboratory.

MEASUREMENTS AND MAIN RESULTS

Fine particle fraction was not different between the Tyvaso Inhalation System and vibrating mesh nebulizer (0.78 ± 0.04 vs 0.77 ± 0.08, respectively; p = 0.79). The vibrating mesh nebulizer delivered the same or greater inhaled treprostinil than the Tyvaso Inhalation System in every simulated model and condition. When using the vibrating mesh nebulizer, delivery was highest when using high-frequency oscillator ventilator in the neonatal and pediatric models, and with the nebulizer in the distal position in the adult model.

CONCLUSIONS

The vibrating mesh nebulizer is a suitable alternative to the Tyvaso Inhalation System for inhaled treprostinil delivery. Fine particle fraction is similar between devices, and vibrating mesh nebulizer delivery meets or exceeds delivery of the Tyvaso Inhalation System. Delivery for infants and children during high-frequency oscillator ventilator with the vibrating mesh nebulizer may result in higher than expected dosages.

Inhaled treprostinil via the Tyvaso Inhalation System through a tracheostomy

A 20-year-old man with pulmonary arterial hypertension secondary to systemic sclerosis was admitted to our hospital. Prior to admission, his PAH had been successfully managed with the use of tadalafil, ambrisentan and inhaled Tyvaso. Owing to respiratory failure from vocal cord paralysis, he underwent an emergent tracheotomy. The delivery of inhaled Tyvaso through a tracheostomy tube was explored. Post-tracheostomy, the patient continued his ability to self-administer the medication. His WHO functional classification, brain natriuretic peptide levels, and echocardiograms were not significantly different when Tyvaso was administered via tracheostomy compared with oral administration. This case report summarises the method used to deliver Tyvaso via a tracheostomy tube, which proved to be successful in this patient.

Evaluation of US20150011555. An inhaled IP receptor agonist for the treatment of pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a rare disease for which IP receptor agonists provide one of the main classes of treatment. Currently available agents tend to lack receptor selectivity.

AREAS COVERED

Four salts of 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid, crystalline forms and compositions of each of these salts, and their use to treat conditions mediated by IP receptor activation, in particular PAH, are claimed. The claimed salts are particularly suited for delivery via inhalation and inhalation devices for their administration are claimed.

EXPERT OPINION

This IP receptor agonist represents the first example of selecting a compound to treat PAH that was designed for delivery via inhalation. It indicates Novartis' desire to establish a broad portfolio of respiratory products.

Current state and novel approaches of antiplatelet therapy

An unresolved problem with clinical use of antiplatelet therapy is that a significant number of individuals either still get thrombosis or run the risk of life-threatening bleeding. Antiplatelet drugs are widely used clinically, either chronically for people at risk of athero/thrombotic disease or to prevent thrombus formation during surgery. However, a subpopulation may be resistant to standard doses, while the platelet targets of these drugs are also critical for the normal hemostatic function of platelets. In this review, we will briefly examine current antiplatelet therapy and existing targets while focusing on new potential approaches for antiplatelet therapy and improved monitoring of effects on platelet reactivity in individuals, ultimately to improve antithrombosis with minimal bleeding. Primary platelet adhesion-signaling receptors, glycoprotein (GP)Ib-IX-V and GPVI, that bind von Willebrand factor/collagen and other prothrombotic factors are not targeted by drugs in clinical use, but they are of particular interest because of their key role in thrombus formation at pathological shear.

Experimentation with aerosol bonsetan, pirfenidone, treprostinil and sidenafil

INTRODUCTION

Pulmonary hypertension (PH) has been identified either as a symptom or a primary entity. Several drugs are already on the market and other are being investigated. Idiopathic pulmonary fibrosis (IPF) is also a disease were several drugs are being investigated.

MATERIALS AND METHODS

Three jet nebulizers and three ultrasound nebulizers were used for our experiments with seven different residual cups and four different loadings. Bonsetan, treprostinil, sidenafil and pirfenidone were modified in order to be produced as aerosol in an effort to identify parameters which influence the droplet size production size.

RESULTS

The four-way ANOVA on droplet size using the jet nebulizers revealed two statistically significant factors, drug (F=6.326, P=0.0007) and residual cup (F=4.419, P=0.0007), and their interaction term (F=5.829, P<0.0001). Drugs bonsetan and pirfenidone produce equally the lowest mean droplet size (2.63 and 2.80 respectively) as compared to other two drug mean sizes. The ANOVA results, concerning the ultrasound nebulizers, revealed only the nebulizers as producing significant effect on droplet size (F=4.753, P=0.037).

DISCUSSION

Our study indicates the importance of the initial drug design formulation. Moreover, further investigation of the residual cup design is an additional parameter that can assist in the optimal droplet size production, indifferently of the drug formulation.

Pulmonary arterial hypertension: basis of sex differences in incidence and treatment response

Pulmonary arterial hypertension (PAH) is a complex disease characterized by elevated pulmonary arterial pressure, pulmonary vascular remodelling and occlusive pulmonary vascular lesions, leading to right heart failure. Evidence from recent epidemiological studies suggests the influence of gender on the development of PAH with an approximate female to male ratio of 4:1, depending on the underlying disease pathology. Overall, the therapeutic strategy for PAH remains suboptimal with poor survival rates observed in both genders. Endogenous sex hormones, in particular 17β oestradiol and its metabolites, have been implicated in the development of the disease; however, the influence of sex hormones on the underlying pathobiology remains controversial. Further understanding of the influence of sex hormones on the normal and diseased pulmonary circulation will be critical to our understanding the pathology of PAH and future therapeutic strategies. In this review, we will discuss the influence of sex hormones on the development of PAH and address recent controversies.

Parenteral and inhaled prostanoid therapy in the treatment of pulmonary arterial hypertension

Since continuous IV epoprostenol was approved in the U.S., parenteral prostanoid therapy has remained the gold standard for the treatment of patients with advanced pulmonary arterial hypertension (PAH). Prostanoid agents can be administered as continuous intravenous infusions, as continuous subcutaneous infusions and by intermittent nebulization therapy. This article presents data from clinical trials of available prostanoid agents, and their varied routes of administration. The varied routes of administration allow for the incremental use of this class of agents in advanced PAH, and if PAH progresses. Prostanoids will remain a major component of PAH therapy for the foreseeable future.

Pulmonary arterial hypertension: new insights into the optimal role of current and emerging prostacyclin therapies

Pulmonary arterial hypertension (PAH), which is a subset of pulmonary hypertension, is a group of diseases distinguished by vascular remodeling of the small pulmonary arteries with associated elevated pulmonary arterial pressure and right ventricular failure. This progressive and sometimes fatal disease occurs as an idiopathic disease or as a component of other disease states. Estimates of the incidence of PAH have varied from 5 to 52 cases/1 million population. Symptoms begin with shortness of breath with exertion and progress to dyspnea with normal activities and, finally, dyspnea at rest. Untreated patients with PAH have a 1-, 3-, and 5-year survival rate of 68%, 48%, and 34%, respectively. Treated, the survival rates improve to 91% to 97% after 1 year and 84% to 91% after 2 years. The current definition of PAH consists of 3 specific hemodynamic assessments confirmed by right heart catheterization findings. One of several important pathophysiologic mechanisms involved in PAH is pulmonary vascular remodeling, which is caused by endothelial and smooth muscle cell hyperproliferation. This is coincident with overexpression of the vasoconstrictor endothelin-1 and a reduction in the vasodilators nitric oxide and prostacyclin, which further impedes proper vasomotor tone, among other effects. Prostacyclin therapies augment the decreased prostacyclin levels in patients with PAH. The currently approved prostacyclins for the treatment of PAH include epoprostenol, iloprost, and treprostinil. Among the 3 medications, the delivery options include intravenous infusion, subcutaneous infusion, and inhaled formulations. Epoprostenol has been shown to have a positive effect on survival in patients with PAH. All prostacyclins have demonstrated improvements in functional class, exercise tolerance, and hemodynamics in patients with PAH. Intravenously and subcutaneously administered formulations of prostacyclins require continuous infusion pump administration, which presents clinical challenges for both the patient and the care provider. Dosing must be individualized and also presents a clinical challenge. Inhaled formulations seem efficacious in moderately symptomatic patients with PAH and might be appropriate when combined with an oral medication. Combination therapies are commonly used in clinical practice, with the decision to do so based on randomized controlled trial data and case study evidence. The present report provides an overview of PAH, the scientific rationale for treatment with prostacyclin therapy, and the benefits and risks of prostacyclin therapy, both as monotherapy and combined with other medications approved for the treatment of PAH.

Efficacy and Safety of Oral Treprostinil Monotherapy for the Treatment of Pulmonary Arterial Hypertension

Background—

Pulmonary arterial hypertension (PAH) is a progressive, fatal disease with no cure. Parenteral and inhaled prostacyclin analogue therapies are effective for the treatment of PAH, but complicated administration requirements can limit the use of these therapies in patients with less severe disease. This study was designed to evaluate the safety and efficacy of the oral prostacyclin analogue treprostinil diolamine as initial treatment for de novo PAH.

Methods and Results—

Three hundred forty-nine patients (intent-to-treat population) not receiving endothelin receptor antagonist or phosphodiesterase type-5 inhibitor background therapy were randomized (treprostinil, n=233; placebo, n=116). The primary analysis population (modified intent-to-treat) included 228 patients (treprostinil, n=151; placebo, n=77) with access to 0.25-mg treprostinil tablets at randomization. The primary end point was change from baseline in 6-minute walk distance at week 12. Secondary end points included Borg dyspnea index, clinical worsening, and symptoms of PAH. The week 12 treatment effect for 6-minute walk distance (modified intent-to-treat population) was 23.0 m ( P =0.0125). For the intent-to-treat population, 6-minute walk distance improvements were observed at peak (26.0 m; P =0.0001) and trough (17.0 m; P =0.0025) plasma study drug concentrations. Other than an improvement in the combined 6-minute walk distance/Borg dyspnea score, there were no significant changes in secondary end points. Oral treprostinil therapy was generally well tolerated; the most common adverse events (intent-to-treat) were headache (69%), nausea (39%), diarrhea (37%), and pain in jaw (25%).

Conclusions—

Oral treprostinil improves exercise capacity in PAH patients not receiving other treatment. Oral treprostinil could provide a convenient, first-line prostacyclin treatment option for PAH patients not requiring more intensive therapy.

Clinical Trial Registration:—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00325403 .

Perioperative anesthesiological management of patients with pulmonary hypertension

Pulmonary hypertension is a major reason for elevated perioperative morbidity and mortality, even in noncardiac surgical procedures. Patients should be thoroughly prepared for the intervention and allowed plenty of time for consideration. All specialty units involved in treatment should play a role in these preparations. After selecting each of the suitable individual anesthetic and surgical procedures, intraoperative management should focus on avoiding all circumstances that could contribute to exacerbating pulmonary hypertension (hypoxemia, hypercapnia, acidosis, hypothermia, hypervolemia, and insufficient anesthesia and analgesia). Due to possible induction of hypotonic blood circulation, intravenous vasodilators (milrinone, dobutamine, prostacyclin, Na-nitroprusside, and nitroglycerine) should be administered with the greatest care. A method of treating elevations in pulmonary pressure with selective pulmonary vasodilation by inhalation should be available intraoperatively (iloprost, nitrogen monoxide, prostacyclin, and milrinone) in addition to invasive hemodynamic monitoring. During the postoperative phase, patients must be monitored continuously and receive sufficient analgesic therapy over an adequate period of time. All in all, perioperative management of patients with pulmonary hypertension presents an interdisciplinary challenge that requires the adequate involvement of anesthetists, surgeons, pulmonologists, and cardiologists alike.