Comparing the efficacy and safety of low, medium, and high dosages of selexipag for treating pulmonary hypertension: A systematic review and meta-analysis

BACKGROUND

The maintenance dosage of selexipag is categorized as low, medium or high. In order to assess the efficacy and safety of different dosages of selexipag for the risk stratification of pulmonary arterial hypertension (PAH), we performed a systematic review and meta-analysis.

METHODS

Studies assessing PAH risk stratification indices, such as the World Health Organization functional class (WHO-FC), six-minute walk distance (6MWD), N-terminal pro-B-type natriuretic peptide (NT-proBNP) level, right atrial pressure (RAP), cardiac index (CI) and mixed venous oxygen saturation (SvO2), were included.

RESULTS

Thirteen studies were included. Selexipag led to improvements in the 6MWD (MD: 24.20 m, 95% CI: 10.74-37.67), NT-proBNP (SMD: -0.41, 95% CI: -0.79-0.04), CI (MD: 0.47 L/min/m2, 95% CI: 0.17-0.77) and WHO-FC (OR: 0.564, 95% CI: 0.457-0.697). Subgroup analysis demonstrated that all three dosages improved the 6MWD. A moderate dosage led to improvements in the CI (MD: 0.30 L/min/m2, 95% CI: 0.15-0.46) and WHO-FC (OR: 0.589, 95% CI: 0.376-0.922). Within 6 months of treatment, only the WHO-FC and CI were significantly improved (OR: 0.614, 95% CI: 0.380-0.993; MD: 0.30 L/min/m2, 95% CI: 0.16-0.45, respectively). More than 6 months of treatment significantly improved the 6MWD, WHO-FC and NT-proBNP (MD: 40.87 m, 95% CI: 10.97-70.77; OR: 0.557, 95% CI: 0.440-0.705; SMD: -0.61, 95% CI: -1.17-0.05, respectively).

CONCLUSIONS

Low, medium, and high dosages of selexipag all exhibited good effects. When treatment lasted for more than 6 months, selexipag exerted obvious effects, even in the low-dosage group. This finding is important for guiding individualized treatments.

Should we use the oral selective IP receptor agonist selexipag off-label in children with pulmonary arterial hypertension?

We discuss the currently available data on the use of the prostacyclin mimetic selexipag in children and adolescents with pulmonary arterial hypertension (PAH). Future indications may include transitioning from intravenous prostacyclin/prostacyclin analog to oral selexipag, and vice versa, or adding selexipag as a third oral PAH-targeted agent in children not responding well to dual PAH therapy.

The metabolism and drug-drug interaction potential of the selective prostacyclin receptor agonist selexipag

1. The metabolism of selexipag has been studied in vivo in man and the main excreted metabolites were identified. Also, metabolites circulating in human plasma have been structurally identified and quantified. 2. The main metabolic pathway of selexipag in man is the formation of the active metabolite ACT-333679. Other metabolic pathways include oxidation and dealkylation reactions. All primary metabolites undergo subsequent hydrolysis of the sulphonamide moiety to their corresponding acids. ACT-333679 undergoes conjugation with glucuronic acid and aromatic hydroxylation to P10, the main metabolite detected in human faeces. 3. The formation of the active metabolite ACT-333679 is catalysed by carboxylesterases, while the oxidation and dealkylation reactions are metabolized by CYP2C8 and CYP3A4. CYP2C8 is the only P450 isoform catalysing the aromatic hydroxylation to P10. CYP2C8 together with CYP3A4 are also involved in the formation of several minor ACT-333679 metabolites. UGT1A3 and UGT2B7 catalyse the glucuronidation of ACT-333679. 4. The potential of selexipag to inhibit or induce cytochrome P450 enzymes or drug transport proteins was studied in vitro. Selexipag is an inhibitor of CYP2C8 and CYP2C9 and induces CYP3A4 and CYP2C9 in vitro. Also, selexipag inhibits the transporters OATP1B1, OATP1B3, OAT1, OAT3, and BCRP. However, due to its low dose and relatively low unbound exposure, selexipag has a low potential for causing drug-drug interactions.

Pharmacokinetics of the selective prostacyclin receptor agonist selexipag in rats, dogs and monkeys

1. This study examined the pharmacokinetics, distribution, metabolism and excretion of the selective prostacyclin receptor agonist selexipag (NS-304; ACT-293987) and its active metabolite MRE-269 (ACT-33679). The compounds were investigated following oral and/or intravenous administration to intact rats, dogs and monkeys, and bile-duct-cannulated rats and dogs. 2. After oral administration of [¹⁴C]selexipag, selexipag was well absorbed in rats and dogs with total recoveries of over 90% of the dose, mainly in the faeces. Biliary excretion was the major elimination pathway for [¹⁴C]MRE-269 as well as [¹⁴C]selexipag, while renal elimination was of little importance. [¹⁴C]Selexipag-related radioactivity was secreted into the milk in lactating rats. 3. Plasma was analysed for total radioactivity, selexipag and MRE-269 in rats and monkeys. Selexipag was negligible in rat plasma due to extensive metabolism, and MRE-269 was present in rat and monkey plasma. A species difference was clearly evident when selexipag was incubated in rat, dog and monkey plasma. 4. Total radioactivity was rapidly distributed to tissues. The highest concentrations were found in the bile duct and liver without significant accumulation or persistence, while there was limited melanin-associated binding, penetration of the blood-brain barrier and placental transfer of drug-related materials.