Integrated pharmacokinetics and pharmacodynamics of epoprostenol in healthy subjects

Therapeutic approaches for pulmonary hypertension in patients with chronic kidney disease

PURPOSE OF REVIEW

Pulmonary hypertension is a common comorbidity in patients with chronic kidney disease (CKD), but therapeutic options are limited. We discuss the epidemiology of pulmonary hypertension in patients with CKD and review therapies for pulmonary hypertension with a focus on emerging treatments for pulmonary arterial hypertension (PAH).

RECENT FINDINGS

The definition of pulmonary hypertension has been updated to a lower threshold of mean pulmonary artery pressures of more than 20 mmHg, potentially leading to more patients with CKD to qualify for the diagnosis of pulmonary hypertension. Endothelin receptor antagonists, a class of medications, which demonstrated efficacy in patients with PAH, have been shown to slow progression of CKD, but their efficacy in lowering pulmonary artery pressures and their effects on reducing cardiovascular mortality in this population remains unproven. Sotatercept, a novel activin signaling inhibitor, which was previously studied in dialysis patients has been shown to increase exercise capacity in patients with PAH. These studies may lead to new specific therapies for pulmonary hypertension in patients with CKD.

SUMMARY

Pulmonary hypertension is common in patients with CKD. Although our understanding of factors leading to pulmonary hypertension in this population have evolved, evidence supporting disease-specific therapy in CKD is limited arguing for larger, long-term studies.

Does Food Affect the Pharmacokinetics of Non-orally Delivered Drugs? A Review of Currently Available Evidence

The food effects for orally administered drugs have been widely investigated and reviewed. In contrast, our knowledge of food effects for non-orally administered drugs is scarce. In this review paper, we did a literature survey to collect clinical food effect data for non-orally administered drugs. Our survey retrieved 18 drugs, including thirteen intravenously (IV), two subcutaneously (SC), one intradermally (ID), one pulmonary, and one rectally administered drug. The food effect data show that food intake can increase the absorption of SC and ID administered peptides and proteins with MW < 30 kDa by 30-50%. On the other hand, food intake can increase the elimination of IV and inhaled drugs with moderate and high hepatic extraction and reduce drug exposure by up to 35%. The food effect knowledge can be used to mitigate potential efficacy and safety risks of non-orally administered drugs.

Epoprostenol for the treatment of pulmonary arterial hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a rare, progressive, and severe disease. Since the first demonstration of survival benefit of intravenous epoprostenol in monotherapy in 1996, prostanoids remain the cornerstone for PAH patients at high risk. This review is essential to understand the current situation of this drug among all the therapeutic possibilities concerning this entity.Areas covered: The aim of this article is to review the pharmacological properties of epoprostenol and to update its clinical evidence in different specific clinical scenarios. A deep literature search was carried out on the MEDLINE database for published literature before March 2021.Expert opinion: Epoprostenol is still the best treatment option for high-risk PAH patients. Nevertheless, there are many unsolved questions: drug dosing, its use in combination therapy with other pulmonary vasodilators, and the utility in PAH associated with connective tissue disease, congenital heart disease, or pulmonary veno-occlusive disease are only a few examples. Its safety and efficacy are supported by clinical trials, observational work, and experience, both as monotherapy and in combination therapy. Epoprostenol should be considered a destination treatment in high-risk patients and not only as a bridge to pulmonary transplantation. However, it remains underused in clinical practice.

Novel Toxicology Program to Support the Development of Inhaled VentaProst

Currently, off-label continuous administration of inhaled epoprostenol is used to manage hemodynamics during mitral valve surgery. A toxicology program was developed to support the use of inhaled epoprostenol during mechanical ventilation as well as pre- and postsurgery via nasal prongs. To support use in patients using nasal prongs, a Good Laboratory Practice (GLP), 14-day rat, nose-only inhalation study was performed. No adverse findings were observed at ∼50× the dose rate received by patient during off-label use. To simulate up to 48 hours continuous aerosol exposure during mechanical ventilation, a GLP toxicology study was performed using anesthetized, intubated, mechanically ventilated dogs. Dogs inhaled epoprostenol at approximately 6× and 13× the dose rate reported in off-label human studies. This novel animal model required establishment of a dog intensive care unit providing sedation, multisystem support, partial parenteral nutrition, and management of the intubated mechanically ventilated dogs for the 48-hour duration of study. Aerosol was generated by a vibrating mesh nebulizer with novel methods required to determine dose and particle size in-vitro. Continuous pH 10.5 epoprostenol was anticipated to be associated with lung injury; however, no adverse findings were observed. As no toxicity at pH 10.5 was observed with a formulation that required refrigeration, a room temperature stable formulation at pH 12 was evaluated in the same ventilated dog model. Again, there were no adverse findings. In conclusion, current toxicology findings support the evaluation of inhaled epoprostenol at pH 12 in surgical patients with pulmonary hypertension for up to 48 hours continuous exposure.

Management of the patient with pulmonary arterial hypertension receiving intravenous prostacyclin: an expert nurse practical guide

Pulmonary arterial hypertension (PAH) is a severely disabling disorder characterized by elevated pulmonary artery pressure ultimately leading to right heart failure and death. Treatment options have significantly increased over the past decade. Intravenous prostacyclins remain the treatment of choice for advanced PAH, leading to long-term clinical benefits and improved survival. Their administration requires a high level of nursing competency and presents considerable challenges for patients and caregivers. This article reviews the characteristics of currently available intravenous prostacyclins and provides a practical guide for nurses who may have had limited exposure to intravenous prostacyclins and their unique dosing, side effects, and titration characteristics.

Epoprostenol (Veletri®, Caripul®): a review of its use in patients with pulmonary arterial hypertension

A bioequivalent formulation of intravenous epoprostenol containing the excipients arginine and sucrose (epoprostenol AS) (Veletri®, Caripul®) is approved in the USA, UK, and other countries for the treatment of pulmonary arterial hypertension (PAH), and has improved thermal stability compared with epoprostenol containing glycine and mannitol (epoprostenol GM) (Flolan®). Epoprostenol, a synthetic prostacyclin, is a potent pulmonary vasodilator. Epoprostenol GM was originally approved for use as a long-term continuous infusion in patients with PAH nearly 20 years ago in the USA; however, this formulation has limited stability at room temperature, and requires the use of cooling or frequent medication changes during administration. The prolonged thermal stability of epoprostenol AS compared with epoprostenol GM allows for its extended administration at room temperature and/or refrigerated storage of prepared solutions. This article summarizes the pharmacology of epoprostenol AS and reviews its therapeutic use in adult patients with PAH. In clinical trials, epoprostenol AS provided sustained efficacy in terms of hemodynamic and symptomatic outcomes, and was generally well tolerated after transitioning from stable epoprostenol GM therapy and during an open-label extension study. Furthermore, there was a significant increase in the treatment convenience with epoprostenol AS compared with epoprostenol GM. Therefore, epoprostenol AS is a valuable therapeutic option that has the potential to overcome some of the limitations of long-term intravenous epoprostenol therapy in patients with PAH.

Two formulations of epoprostenol sodium in the treatment of pulmonary arterial hypertension: EPITOME-1 (epoprostenol for injection in pulmonary arterial hypertension), a phase IV, open-label, randomized study

BACKGROUND

Epoprostenol sodium with arginine-mannitol excipients (epoprostenol AM; Veletri [Actelion Pharmaceuticals Ltd, Allschwil, Switzerland]) and epoprostenol sodium with glycine-mannitol excipients (epoprostenol GM; Flolan [GlaxoSmithKline, Triangle Park, NC]) are intravenous treatments for pulmonary arterial hypertension (PAH). Epoprostenol AM contains different inactive excipients, resulting in greater stability at room temperature compared with epoprostenol GM.

METHODS

In this prospective, multicenter, open-label, randomized, phase IV exploratory study, epoprostenol-naïve patients in need of injectable prostanoid therapy were randomized 2:1 to open-label epoprostenol AM or epoprostenol GM. The study period was 28 days, followed by a 30-day safety follow-up. Study aims were to descriptively compare the safety, tolerability, drug metabolite levels, and treatment effects of epoprostenol AM and epoprostenol GM in PAH. Statistical analysis was descriptive only because of the exploratory nature of the study.

RESULTS

Thirty patients with PAH (18-70 years, 24 women, 20 idiopathic PAH) were randomized to epoprostenol AM (n = 20) or epoprostenol GM (n = 10). Most frequently reported adverse events included jaw pain, headache, nausea, and flushing. Two deaths occurred during the study period, and 1 death occurred during the 30-day safety follow-up period, all in patients receiving epoprostenol AM. All deaths were classified by the treating physician as unrelated to epoprostenol AM. The median (range) change from baseline to day 28 in 6-minute walk distance was 36 m (-127 to 210 m) and 49 m (-44 to 110 m) for the epoprostenol AM and epoprostenol GM groups, respectively.

CONCLUSIONS

In this randomized clinical study of epoprostenol AM in PAH, use of this novel preparation with greater room temperature stability was well tolerated.

Comparative pharmacokinetic, pharmacodynamic, safety, and tolerability profiles of 3 different formulations of epoprostenol sodium for injection in healthy men

BACKGROUND

Epoprostenol sodium for injection is approved for the treatment of severe cases of primary pulmonary arterial hypertension. Currently, there are 3 approved formulations of this drug containing the same active ingredient (epoprostenol sodium) but differing with regard to excipients. When compared with epoprostenol sodium formulated with glycine-mannitol (epoprostenol GM), 2 new formulations of epoprostenol sodium, one formulated with arginine-mannitol (epoprostenol AM) and one formulated with arginine-sucrose (epoprostenol AS), have improved stability after reconstitution and dilution. The biocomparability of epoprostenol AM and epoprostenol GM, with regard to pharmacokinetic (PK), pharmacodynamic (PD), safety, and tolerability profiles, has been shown previously.

OBJECTIVE

This study compared PK, PD, safety, and tolerability profiles of the 3 different formulations of epoprostenol sodium for injection.

METHODS

This was a prospective, single-center, open-label, 2-period, 2-treatment, randomized, crossover, ascending dose study in 2 parts. Twenty healthy men in part 1 and 20 different individuals in part 2 received epoprostenol AM and epoprostenol AS and epoprostenol GM and epoprostenol AS, respectively, in a crossover fashion, as sequential IV infusions of 2, 4, 6, and 8 ng/kg/min for 2 hours each. In each part, the PK profile of epoprostenol was characterized via analysis of the concentration-time profiles of its 2 primary metabolites: 6-keto-prostacyclin F1α and 6,15-diketo-13,14-dihydro-prostacyclin F1α. The effect of the formulations was assessed using the 90% CI of the geometric mean ratio calculated for the exposure PK parameters. The PD variables cardiac output, cardiac index, and heart rate were assessed using echocardiography. Adverse events were recorded through the study.

RESULTS

The plasma concentration versus time curves of epoprostenol AM and epoprostenol AS in part 1 and epoprostenol GM and epoprostenol AS in part 2 were similar in shape and almost superimposable. For each study part, the 90% CIs of ratios of geometric means for AUC0-∞ of the assessed epoprostenol formulations were within the range for bioequivalence (0.8-1.25). The increases in cardiac output, cardiac index, and heart rate resulting from infusion with epoprostenol sodium were comparable between all formulations, with maximum values attained after 8 hours. Almost all study participants reported at least one treatment-emergent adverse event, the most common being headache, which was reported in 80% to 85% of study participants.

CONCLUSIONS

Overall, the PK, PD, safety, and tolerability profiles of the 3 formulations of epoprostenol sodium for injection are comparable and meet the criteria of bioequivalence. Australian New Zealand Clinical Trials Registry identifier: ACTRN12612001086853.