iloprost and selexipag

A 25-year-old woman was admitted to our hospital with severe pulmonary arterial hypertension associated with systemic lupus erythematosus (SLE-PAH). Her mean pulmonary arterial pressure was 56 mmHg, and her SLE Disease Activity Index-2 K score was 14 on admission. In addition to a strong immunosuppressive regimen, which included steroid pulse therapy followed by high-dose oral prednisolone (1 mg/kg) and intravenous cyclophosphamide, an upfront combination of vasodilator therapy, including oral tadalafil, macitentan, and intravenous epoprostenol, was administered in the early phase. Two months later, her mean pulmonary arterial pressure was 29 mmHg, and her other haemodynamic markers showed significant improvement. She refused to start life-long intravenous epoprostenol therapy and so was switched to oral selexipag and inhaled iloprost. The transition was successful, and she has experienced no exacerbations of SLE-PAH during the 10 months since the onset of pulmonary arterial hypertension. To the best of our knowledge, this is the first report of intravenous epoprostenol being switched to alternative oral and inhaled therapy in a patient with SLE-PAH. In combination with adequate immunosuppressive therapy, it is probably easier to make this transition in patients with SLE-PAH than in those with pulmonary arterial hypertension of a different aetiology. Continuous infusion of epoprostenol can have potentially life-threatening complications and a detrimental effect on the quality of life. Our alternative treatment strategy was successful, and we hope that it will prove beneficial in other cases.

Topics: Acetamides; Adult; Epoprostenol; Female; Humans; Hypertension, Pulmonary; Iloprost; Lupus Erythematosus, Systemic; Pulmonary Arterial Hypertension; Pyrazines; Quality of Life

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pulmonary vascular resistance that can lead to right ventricular failure and death. The use of medications that affect the prostacyclin pathway is an important treatment strategy in PAH. Inhaled iloprost is a prostacyclin analogue, and selexipag is an oral, non-prostanoid, prostacyclin IP receptor agonist. Data are limited on transitioning patients from inhaled iloprost to selexipag. In this case report, we describe the successful transition of a 57-year-old female with heritable PAH from inhaled iloprost to selexipag over 8 weeks in an out-patient setting. After initiation of selexipag, the patient's inhaled iloprost dose was gradually reduced and eventually discontinued. The patient tolerated the transition well with stable symptoms, 6-minute walk distance, and pulmonary hemodynamics. Additional studies are needed to better define the comparative efficacy and safety of inhaled iloprost and selexipag.

Topics: Acetamides; Antihypertensive Agents; Female; Humans; Hypertension, Pulmonary; Iloprost; Middle Aged; Pulmonary Arterial Hypertension; Pyrazines

Prostacyclin (PGI

Topics: Acetamides; Acetates; Animals; beta-Arrestins; Cell Proliferation; CHO Cells; Contractile Proteins; Cricetinae; Cricetulus; Cyclic AMP; Epoprostenol; Extracellular Matrix; Humans; Hypertension, Pulmonary; Iloprost; Male; Muscle Contraction; Muscle Relaxation; Pyrazines; Rats; Rats, Inbred SHR; Rats, Wistar; Receptors, Epoprostenol

The prostacyclin (IP) receptor agonists, treprostinil, iloprost and the selexipag metabolite, MRE-269 (ACT-333679) were evaluated in rat distal pulmonary blood vessels. Small pulmonary arteries and veins were pre-contracted with the thromboxane mimetic, U46619 (25 and 100nM, respectively), and relaxation determined with and without IP receptor antagonists, RO1138452 and RO3244794. In arteries, treprostinil was a more potent vasorelaxant than iloprost, while the efficacy of iloprost was greater. In pulmonary arteries, treprostinil-induced relaxation was essentially abolished by both IP antagonists (1μM), while responses to iloprost were partially inhibited. Both treprostinil and iloprost were equipotent, prominently relaxing pulmonary veins with responses being similarly and partially sensitive to IP antagonists. In contrast, RO1138452 failed to inhibit relaxations to MRE-269 in either pulmonary arteries or veins, suggesting no involvement of typical IP receptors. Thus, rat pulmonary tissues cannot be considered appropriate to assess classical IP receptors using the proposed highly selective non-prostanoid agonist MRE-269, contrasting with the IP receptor agonism profile of prostacyclin analogues, iloprost and treprostinil.

Topics: Acetamides; Acetates; Animals; Benzofurans; Benzyl Compounds; Epoprostenol; Female; Iloprost; Imidazoles; Male; Propionates; Pulmonary Artery; Pulmonary Veins; Pyrazines; Rats; Rats, Sprague-Dawley; Receptors, Epoprostenol; Vasodilation

Selexipag [2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl)acetamide] is an orally available prostacyclin (PGI(2)) receptor (IP receptor) agonist that is chemically distinct from PGI(2) and is in clinical development for the treatment of pulmonary arterial hypertension. Selexipag is highly selective for the human IP receptor in vitro, whereas analogs of PGI(2) can activate prostanoid receptors other than the IP receptor. The goal of this study was to determine the impact of selectivity for the IP receptor on gastric function by measuring 1) contraction of rat gastric fundus ex vivo and 2) the rates of gastric emptying and intestinal transport in response to selexipag in comparison with other PGI(2) analogs. The rat gastric fundus expresses mRNA encoding multiple prostanoid receptors to different levels: prostaglandin E receptor 1 (EP(1)) > prostaglandin E receptor 3 (EP(3)), IP receptor > prostaglandin D(2) receptor 1, thromboxane receptor. Selexipag and metabolite {4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}acetic acid (ACT-333679) did not contract gastric fundus at concentrations up to 10(-3) M. In contrast, the PGI(2) analogs iloprost and beraprost evoked concentration-dependent contraction of gastric fundus. Contraction to treprostinil was observed at high concentration (10(-4) M). Contraction to all PGI(2) analogs was mediated via activation of EP(3) receptors, although EP(1) receptors also contributed to the contraction of gastric fundus to iloprost and beraprost. Antagonism of IP receptors did not affect responses. Oral selexipag did not significantly alter gastric function in vivo, as measured by rates of stomach emptying and intestinal transport, whereas beraprost slowed gastrointestinal transport. The high functional selectivity of selexipag and ACT-333679 for the IP receptor precludes a stimulatory action on gastric smooth muscle and may help minimize gastric side effects such as nausea and vomiting.

Topics: Acetamides; Animals; Dinoprostone; Dose-Response Relationship, Drug; Epoprostenol; Gastric Emptying; Gastrointestinal Transit; Humans; Iloprost; Male; Muscle Contraction; Pulmonary Artery; Pyrazines; Rats; Receptors, Epoprostenol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stomach