selexipag and beraprost

Prostacyclin is produced in vascular endothelial cells and acts via the IP prostacyclin receptor to cause vasodilation and inhibit smooth muscle cell proliferation and platelet aggregation. Prostacyclin production is reduced in pulmonary arterial hypertension (PAH), and drugs targeting the prostacyclin pathway are one of the pharmacotherapeutic options for PAH. Areas covered: The prostacyclin pathway and drugs that target it are discussed, including synthetic prostacyclin (epoprostenol), prostacyclin analogs (iloprost, treprostinil, beraprost) and selective prostacyclin IP receptor agonists (selexipag). An overview of the development of these therapies, from the earlier agents requiring parenteral administration, through inhaled formulations, to oral products, is provided, together with a summary of data from key clinical trials and registries. Expert commentary: Synthetic prostacyclin and prostacyclin analogs are beneficial for patients with PAH, but they tend to be underused, in part due to the difficulties associated with the administration of parenteral and inhaled formulations. Oral prostacyclin analogs have some limitations with regard to efficacy. The newest agent targeting the prostacyclin pathway, the selective prostacyclin receptor agonist selexipag, is administered orally, and has been shown to reduce a composite morbidity/mortality endpoint. Ongoing studies will help clarify how best to use it in the management of PAH.

Topics: Acetamides; Antihypertensive Agents; Epoprostenol; Humans; Hypertension, Pulmonary; Pyrazines; Receptors, Epoprostenol

Prostacyclin pathway medications have been shown to be highly efficacious in the treatment of pulmonary arterial hypertension (PAH) through multiple prospective clinical trials and more than two decades of clinical experience. The strongest support for prostacyclin use in PAH management is with parenteral administration. Numerous risks and limitations of parenteral delivery systems as well as significant patient burdens restrict widespread parenteral use. Highly effective and tolerable oral prostacyclin preparations to manage PAH have long been sought. We review the development of the oral prostacyclin agents beraprost, treprostinil, and selexipag and including current indications and limitations. Research into new approaches to the management of PAH, expanding indications for existing agents, and development of novel agents are also discussed.. Two oral prostacyclin pathway medications, oral treprostinil and selexipag, were FDA approved in December 2013 and 2015, respectively. Current guidelines recommend use of selexipag in WHO-FC II and III (class 1, level B recommendation) and oral treprostinil in WHO-FC III (class 2b, level B recommendation). The use of these medications is challenging due to complexity in dosing and their side effect profiles which limit patient tolerability and acceptance. There is a promising role for oral prostacyclin pathway medications in patients with PAH. Future investigations are underway of alternative dose regimens and transitioning from parenteral therapies in order to improve efficacy and tolerability.

Topics: Acetamides; Antihypertensive Agents; Epoprostenol; Humans; Hypertension, Pulmonary; Pyrazines

It is well established that the endothelin, nitric oxide and prostacyclin pathways play an important role in the development of pulmonary arterial hypertension (PAH). Indeed, the therapeutic options currently available for the management of PAH all act on one of these mechanistic pathways. However, this is an exciting time for both clinicians and scientists, as increased understanding of the mechanisms involved in the pathogenesis and progression of PAH has resulted in the development of a number of novel therapeutic options. This article highlights how the introduction of new compounds such as macitentan, riociguat and selexipag, which act on the endothelin, nitric oxide and prostacyclin pathways, respectively, have the potential to further improve the prognosis for patients with PAH.

Topics: Acetamides; Animals; Antihypertensive Agents; Benzamides; Clinical Trials as Topic; Drugs, Investigational; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Epoprostenol; Guanylate Cyclase; Humans; Hypertension, Pulmonary; Imatinib Mesylate; Lisuride; Nitric Oxide; Phosphodiesterase 5 Inhibitors; Piperazines; Protein Kinase Inhibitors; Pyrazines; Pyrazoles; Pyrimidines; Serotonin Antagonists; Sulfonamides

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