Safety and Tolerability of High-dose Inhaled Treprostinil in Pulmonary Hypertension

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.

Multidisciplinary Team Managements and Clinical Outcomes in Patients With Pulmonary Arterial Hypertension During the Perinatal Period

Background: Pulmonary arterial hypertension (PAH) patients with pregnancy have high maternal mortality. This study aimed to provide clinical evidence with multidisciplinary team (MDT) management and to evaluate the clinical outcomes in PAH patients during the perinatal period.

Methods: We conducted a retrospective evaluation of PAH patients pregnant at the First Affiliated Hospital of Chongqing Medical University between May 2015 and May 2021.

Results: Twenty-two patients (24 pregnancies) were included in this study and received MDT management, and 21 pregnancies chose to continue pregnancy with cesarean section. Nine (37.5%) were first-time pregnancies at 27.78 ± 6.16 years old, and 15 (62.5%) were multiple pregnancies at 30.73 ± 3.71 years old. The average gestational week at hospitalization and delivery were 29.38 ± 8.63 weeks and 32.37 ± 7.20 weeks, individually. Twenty-one (87.5%) pregnancies received single or combined pulmonary vasodilators. The maternal survival rate of PAH patients reached 91.7%. Fifteen (62.5%) pregnancies were complicated with severe adverse events. Patients with complicated adverse events showed lower percutaneous oxygen saturation (SpO₂), lower albumin, lower fibrinogen, higher pulmonary artery systolic pressure (PASP), higher blood pressure, longer activated partial thromboplastin time, and longer coagulation time. Fourteen (66.7%) pregnancies with cesarean sections were prematurely delivered and 85.7% newborns who survived after the operation remained alive.

Conclusion: The survival rate of parturients with PAH was improved in relation to MDT and pulmonary vasodilator therapy during the perinatal period compared with previous studies. SpO₂, albumin, PASP, blood pressure, and coagulation function should be monitored carefully in PAH patients during pregnancy.

Survival and drug persistence in patients receiving inhaled treprostinil at doses greater than 54 µg (nine breaths) four times daily

Treprostinil is a prostacyclin approved for the treatment of pulmonary arterial hypertension. Commercial data sets indicate that approximately 20-25% of patients are prescribed a higher dose than the maximum recommended dosage of nine breaths per treatment session (bps) (54 μg), four times a day (QID) and numerous studies have demonstrated the safety of doses >9 bps QID. This phase 4, retrospective analysis of specialty pharmacy records assessed the effects of inhaled treprostinil at doses >9 bps QID. Patients receiving inhaled treprostinil between September 2009 and June 2018 were included, and a random sampling of 5000 patients was selected for further analysis. Subjects were grouped based on the highest dose reached for ≥2 months within a rolling six-month window and were followed for up to three years. Of the total of 5000 patients analyzed, 28.5% received >9 bps QID. Survival rates were significantly higher in the >9 bps QID dosing group for years one, two, and three (P < 0.001). The time to transition to parenteral therapy was significantly longer for those at doses >9 bps (17.5 months) compared to doses ≤9 bps (9.5 moths; P < 0.0001). Drug persistence was also significantly higher for those taking >9 bps at years 1, 2, and 3 (P < 0.0001). Patients receiving inhaled treprostinil at doses >9 bps QID had a higher rate of survival and drug persistence over a three-year period, suggesting that higher doses may provide clinically relevant benefits while remaining tolerable.

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.

Effects of treprostinil on pulmonary arterial hypertension during surgery for congenital heart disease complicated with severe pulmonary arterial hypertension

BACKGROUND

The aim of this study is to evaluate the effects of treprostinil injection on the control of pulmonary blood pressure in children with congenital heart disease (CHD) complicated by severe pulmonary arterial hypertension (PAH).

METHODS

Eighty children with CHD complicated by severe pulmonary arterial hypertension admitted to our hospital from January 2015 to June 2018 were selected and randomly divided into a control group (N.=40) and a treatment group (N.=40). Based on standard treatment, the treatment group was intravenously infused with 8-12 ng/kg·min treprostinil, while the control group received the same dose of normal saline. Hemodynamic parameters such as BP, AP, P and SpO<inf>2</inf>% were monitored before anesthesia induction (T0), before cardiopulmonary bypass (T1), 1 h after cardiopulmonary bypass (T2) and at the end of cardiopulmonary bypass (T3). Pulmonary arterial pressure parameters (PASP, PADP and PAMP) were measured at T1, T2 and T3 by transesophageal echocardiography.

RESULTS

For the treatment group, the HR values at T2 and T3 were lower than that at T0 (P<0.05). For the control group, HR at T3 was lower than that at T0 (P<0.05). HR at T3 of the treatment group was lower than that of the control group (P<0.05). SpO<inf>2</inf> of the treatment group was higher than that of the control group at T3 (P<0.05). At T2 and T3, PASP, PADP and PAMP of both groups were lower than those before surgery (P<0.05), and the values of the treatment group were lower than those of the control group (P<0.05).

CONCLUSIONS

Treprostinil can improve cardiac function and reduce pulmonary circulation resistance in PAH children.

Ambulatory Transition from Parenteral Prostanoid to Inhaled Treprostinil in Patients with Pulmonary Arterial Hypertension

PURPOSE

The intravenous or subcutaneous delivery of prostanoid drugs for moderate to severe pulmonary arterial hypertension has been fraught with complications and patient dissatisfaction. Combination therapy including inhaled treprostinil is an attractive alternative in clinically stable patients. Uncertainties exist about the patient characteristics and the optimal setting (inpatient versus office/home) for transition.

METHODS

Sixteen stable patients with pulmonary arterial hypertension and favorable risk profile were transitioned from parenteral prostanoid to combination therapy including inhaled treprostinil in the home setting. Nine patients were using intravenous treprostinil, two patients were using subcutaneous treprostinil, and five patients were using intravenous epoprostenol at a median dose of 80 (interquartile range, IQR 72-90), 76.5 (68 and 85), and 28 (IQR 26-30) ng/kg/min respectively. Patients were followed up for a median of 732.5 days after transition (IQR 506.5-1294 days).

RESULTS

Patients tolerated the transition to inhaled treprostinil well without significant change in functional class (81.25% FC I/II before transition vs. 87.5% after), 6-min walk distance [349 m (IQR 226-461 m) to 364 m (IQR 238-565 m), p = 0.09] or NT-proBNP [149 pg/ml (IQR 71.5-383 pg/ml) to 186.5 pg/ml (IQR 83.5-444 pg/ml), p = 0.38]. Hemodynamic data, where available, showed significant improvements in mean pulmonary artery pressure and pulmonary vascular resistance from 36 mmHg (IQR 27-46.5 mmHg) and 5.2 Wood Units (WU) (IQR 3.1-5.6 WU) to 28.5 mmHg (IQR 22-35.5 mmHg) and 3.2 WU (IQR 2.4-4.2 WU) (p-values 0.022 and 0.003). More patients were on triple therapy after transition, and side effects reported were less severe.

CONCLUSION

For select patients, transition from a parenteral prostanoid-based therapy to a combination regimen including inhaled treprostinil in the home setting appears safe and well tolerated.

Pulmonary Hypertension in Intensive Care Units: An Updated Review

Pulmonary hypertension (PH) is a condition associated with high morbidity and mortality. Patients with PH who require critical care usually have severe right ventricular (RV) dysfunction. Although different groups of PH have different etiologies, pulmonary vascular dysfunction is common in these groups. PH can lead to increased pulmonary artery pressure, which can ultimately cause RV failure. Clinicians should be familiar with the presentations of this disease and diagnostic tools. The contributing factors, if present (e.g., sepsis), and coexisting conditions (e.g., arrhythmias) should be identified and addressed accordingly. The preload should be optimized by fluid administration, diuretics, and dialysis, if necessary. On the other hand, the RV afterload should be reduced to improve the RV function with pulmonary vasodilators, such as prostacyclins, inhaled nitric oxide, and phosphodiesterase type 5 inhibitors, especially in group 1 PH. Inotropes are also used to improve RV contractility, and if inadequate, use of ventricular assist devices and extracorporeal life support should be considered in suitable candidates. Moreover, vasopressors should be used to maintain systemic blood pressure, albeit cautiously, as they increase the RV afterload. Measures should be also taken to ensure adequate oxygenation. However, mechanical ventilation is avoided in RV failure. In this study, we reviewed the pathophysiology, manifestations, diagnosis, monitoring, and management strategies of PH, especially in intensive care units.

Mechanism of anti-remodelling action of treprostinil in human pulmonary arterial smooth muscle cells

Treprostinil is applied for pulmonary arterial hypertension (PAH) therapy. However, the mechanism by which the drug achieves its beneficial effects in PAH vessels is not fully understood. This study investigated the effects of treprostinil on PDGF-BB induced remodelling parameters in isolated human pulmonary arterial smooth muscle cells (PASMC) of four PAH patients. The production of TGF-β1, CTGF, collagen type-I and -IV, and of fibronectin were determined by ELISA and PCR. The role of cAMP was determined by ELISA and di-deoxyadenosine treatment. Proliferation was determined by direct cell count. Treprostinil increased cAMP levels dose and time dependently, which was not affected by PDGF-BB. Treprostinil significantly reduced PDGF-BB induced secretion of TGF-β1 and CTGF, both was counteracted when cAMP generation was blocked. Similarly, the PDGF-BB induced proliferation of PASMC was dose dependently reduced by treprostinil through signalling via cAMP—C/EBP-α p42 –p21^(WAf1/Cip1). In regards to extracellular matrix remodelling, treprostinil significantly reduced PDGF-BB—TGF-β1—CTGF induced synthesis and deposition of collagen type I and fibronectin, in a cAMP sensitive manner. In contrast, the deposition of collagen IV was not affected. The data suggest that this action of treprostinil in vessel wall remodelling may benefit patients with PAH and may reduce arterial wall remodelling.

Prostaglandins in asthma and allergic diseases

Prostaglandins are synthesized through the metabolism of arachidonic acid via the cyclooxygenase pathway. There are five primary prostaglandins, PGD₂, PGE₂, PGF₂, PGI₂, and thromboxane B₂, that all signal through distinct seven transmembrane, G-protein coupled receptors. The receptors through which the prostaglandins signal determines their immunologic or physiologic effects. For instance, the same prostaglandin may have opposing properties, dependent upon the signaling pathways activated. In this article, we will detail how inhibition of cyclooxygenase metabolism and regulation of prostaglandin signaling regulates allergic airway inflammation and asthma physiology. Possible prostaglandin therapeutic targets for allergic lung inflammation and asthma will also be reviewed, as informed by human studies, basic science, and animal models.

Tolerability and clinical efficacy of inhaled treprostinil in patients with group 1 pulmonary arterial hypertension

Background

Treprostinil is a prostacyclin analogue that directly vasodilates pulmonary and systemic arterial vascular beds. The United States Food and Drug Administration approved inhaled treprostinil in July 2009 for the treatment of group 1 pulmonary arterial hypertension. Inhaled treprostinil avoids issues with continuous infusion prostanoids. This study describes a single institutional experience with inhaled treprostinil.

Methods

This was a retrospective review of group 1 pulmonary arterial hypertension patients receiving inhaled treprostinil from July 2009 through September 2015. Patient demographics, vital signs, prognostic indicators, pulmonary arterial hypertension assessments, treprostinil dosing, pulmonary arterial hypertension medications, and physician assessment were collected. Prognostic indicators and the physician assessment were used to assess treatment response. A modified Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management (REVEAL) risk score was calculated prior to and after initiation of inhaled treprostinil.

Results

The mean time on inhaled treprostinil for the 16 patients was 21 ± 17 months. A total of 31% discontinued treatment. The New York Heart Association Functional Class, right ventricular size, and right ventricular function improved after inhaled treprostinil. Directional improvement in B-type natriuretic peptide, 6-minute walk distance, right arterial pressure and mean pulmonary artery pressure were also observed. The mean modified REVEAL risk score (RRS) was 7 ± 3 at baseline. The RRS decreased in 7 of the 11 patients that improved and remained stable in 2 patients.

Conclusion

The majority of patients in this consecutive series receiving inhaled treprostinil tolerated treatment. Most patients remained on therapy for over 12 months. Clinical assessments of disease severity all changed directionally toward improvement and the overall risk assessment was improved or stable in 56% by the RRS.

Practical considerations for therapies targeting the prostacyclin pathway

Therapies that target the prostacyclin pathway play a key role in the treatment of both early- and late-stage pulmonary arterial hypertension, and provide significant clinical benefits for patients. A number of agents have been approved, which are administered via intravenous, subcutaneous, inhaled or oral routes. The use of these therapies is associated with practical challenges, relating to the need for up-titration and their routes of administration. We discuss here a number of measures that can be taken to support patients and healthcare professionals in order to address the complexities of using these therapies and to encourage compliance. Providing patients with timely information and education, together with practical advice on managing their medication and associated equipment, assists patients with day-to-day management of therapy. Referral to patient associations and support groups can be of further benefit. With an effective management plan and an experienced multidisciplinary team, the use of therapies that target the prostacyclin pathway can be optimised.

Practical support for patients and HCPs to facilitate the use of therapies that target the PGI₂ pathway in PAHhttp://ow.ly/468S305Dl6m