Selexipag 200 mcg · Tablets

Selexipag is a prostacyclin receptor (IP receptor) agonist that is structurally distinct from prostacyclin. Selexipag is hydrolyzed by carboxylesterase 1 to yield its active metabolite, which is approximately 37-fold as potent as selexipag. Selexipag and the active metabolite are selective for the IP receptor versus other prostanoid receptors (EP1–4, DP, FP, and TP).

The pharmacokinetics of selexipag and its active metabolite have been studied primarily in healthy subjects. The pharmacokinetics of selexipag and the active metabolite, after both single- and multiple-dose oral administration, were dose-proportional up to a single dose of 800 mcg and multiple doses of up to 1,800 mcg twice daily. The pharmacokinetics of selexipag and the active metabolite, after multiple-dose intravenous administration, were dose-proportional in the tested dose range from 450 to 1,800 mcg twice a day.

In healthy subjects, inter-subject variability in exposure (area under the curve over a dosing interval, AUC) at steady-state following oral administration was 43% and 39% for selexipag and the active metabolite, respectively. Intra-subject variability in exposure was 24% and 19% for selexipag and the active metabolite, respectively.

Exposures to selexipag and the active metabolite at steady-state in PAH patients and healthy subjects were similar. The pharmacokinetics of selexipag and the active metabolite in PAH patients were not influenced by the severity of the disease and did not change with time.

The corresponding UPTRAVI tablets and UPTRAVI for injection doses (Table 2) provide similar exposure to the active metabolite in PAH patients at steady-state, whereas the exposure to selexipag is approximately twice as high after intravenous administration compared to oral administration.

Both in healthy subjects and PAH patients, after oral administration, exposure at steady-state to the active metabolite is approximately 3- to 4-fold that of selexipag.

Absorption — The absolute bioavailability of orally administered selexipag is approximately 49%. Upon oral administration, maximum observed plasma concentrations of selexipag and its active metabolite are reached within about 1–3 hours and 3–4 hours, respectively.

Similar exposures were observed in pediatric study patients after taking whole tablets with water, taking with soft food, and dispersing in apple or orange juice.

Distribution — The volume of distribution of selexipag at steady-state is 11.7 L.

Selexipag and its active metabolite are highly bound to plasma proteins (approximately 99% in total and to the same extent to albumin and alpha1-acid glycoprotein).

Metabolism — Selexipag is hydrolyzed to its active metabolite, (free carboxylic acid) in the liver and intestine by carboxylesterases. Oxidative metabolism, catalyzed mainly by CYP2C8 and to a smaller extent by CYP3A4, leads to the formation of hydroxylated and dealkylated products. UGT1A3 and UGT2B7 are involved in the glucuronidation of the active metabolite. Except for the active metabolite, none of the circulating metabolites in human plasma exceeds 3% of the total drug-related material.

Elimination — Elimination of selexipag is predominately via metabolism with a mean terminal half-life of 0.8–2.5 hours. The terminal half-life of the active metabolite is 6.2–13.5 hours. Selexipag does not accumulate following twice daily repeat administration. There is minimal accumulation of the active metabolite upon twice daily repeat administration suggesting that the effective half-life is in the range of 3–4 hours. The total body clearance of selexipag is 17.9 L/hour.

Excretion — In a study in healthy subjects with radiolabeled selexipag, approximately 93% of radioactive drug material was eliminated in feces and only 12% in urine. Neither selexipag nor its active metabolite were found in urine.

Specific Populations — No clinically relevant effects of sex, race, age or body weight on the pharmacokinetics of selexipag and its active metabolite have been observed in healthy subjects or PAH patients.

Drug Interaction Studies — Drug interaction studies have been performed in adult subjects using UPTRAVI tablets.