Macitentan

Macitentan
	File:Macitentan skeletal.svg
Clinical data
Trade names	Opsumit
Synonyms	ACT-064992
Pregnancy; category	US: X (Contraindicated) ; ;
Routes of; administration	Oral
ATC code	C02KX04 (WHO) ;
Legal status
Legal status	US: ℞-only ; FDA approved drug;
Pharmacokinetic data
Metabolism	Hydrolysis, oxidation (CYP3A4)
Excretion	2/3 urine, 1/3 faeces
Identifiers
	IUPAC name N-[5-(4-Bromophenyl)-6-[2-[(5-bromo-2-pyrimidinyl)oxy]ethoxy]-4-pyrimidinyl]-N'-propylsulfamide;
CAS Number	441798-33-0;
PubChem CID	16004692;
ChemSpider	13134960;
ChEBI	CHEBI:76607;
E number	{{#property:P628}}
ECHA InfoCard	{{#property:P2566}}Lua error in Module:EditAtWikidata at line 36: attempt to index field 'wikibase' (a nil value).
Chemical and physical data
Formula	C19H20Br2N6O4S
Molar mass	588.273 g/mol
3D model (JSmol)	Interactive image;
	SMILES Brc1ccc(cc1)c3c(ncnc3OCCOc2ncc(Br)cn2)NS(=O)(=O)NCCC;
	InChI InChI=1S/C19H20Br2N6O4S/c1-2-7-26-32(28,29)27-17-16(13-3-5-14(20)6-4-13)18(25-12-24-17)30-8-9-31-19-22-10-15(21)11-23-19/h3-6,10-12,26H,2,7-9H2,1H3,(H,24,25,27); Key:JGCMEBMXRHSZKX-UHFFFAOYSA-N;

Macitentan (trade name Opsumit) is an endothelin receptor antagonist (ERA) approved for the treatment of pulmonary arterial hypertension (PAH).^[1] The other two ERAs marketed as of 2014 are bosentan and ambrisentan.^[1] Macitentan is a dual ERA, meaning that it acts as an antagonist of two endothelin (ET) receptor subtypes, ET_A and ET_B.^[1] However, macitentan has a 50-fold increased selectivity for the ETA subtype compared to the ETB subtype.^[2] The drug received approval from the U.S. Food and Drug Administration (FDA) on October 13, 2013.^[3]

Mechanism of action

Endothelin and endothelin receptors

Endothelin (ET) is an extremely potent blood vessel constricting substance that is secreted by endothelial cells.^[4] In the lungs, the most common ET form released is ET-1.^[4] ET-1 release can occur through both constitutive and non-constitutive pathways.^[4] Upon release, ET-1 can bind to the ET receptors that are expressed on arterial smooth muscle cells and fibroblasts in the lungs.^[4] ET receptors are G protein coupled receptors and, when activated, lead to an increase in intracellular calcium levels via the Gαq signaling pathway.^[4] The rise in intracellular calcium leads to contraction of the arterial smooth muscle, as well as vascular remodelling due to cell proliferation.^[4] Prolonged constriction and fibrosis are factors in the pathogenesis of PAH.^[1]

Role of macitentan

Macitentan blocks the ET1-dependent rise in intracellular calcium by inhibiting the binding of ET-1 to ET receptors. Blocking of the ETA receptor subtype seems to be of more importance in the treatment of PAH than blocking of ETB, likely because there are higher numbers of ETA receptors than ETB receptors in pulmonary arterial smooth muscle cells.^[4]

Experimental pharmacokinetics

Macitentan has slow association kinetics.^[4] Its potency increases 6.3-fold when it is pre-incubated with pulmonary arterial smooth muscle cells for 120 minutes compared to 10 minutes with pulmonary arterial smooth muscle cells.^[4] Macitentan also has a high receptor occupancy half-life (approximately 17 minutes) compared to bosentan (approximately 70 seconds) and ambrisentan (approximately 40 seconds).^[4] This increased receptor occupancy half-life allows macitentan to act as a non-competitive antagonist of ET receptors.^[4] Bosentan and ambrisentan are both competitive antagonists.^[4]

Pharmacokinetics

Macitentan is taken as a 10 mg oral dose once a day.^[1] Its half-life in humans is about 16 hours and steady state is reached by the third day of administration.^[5] It is absorbed slowly into the plasma.^[6] Macitentan has an active metabolite, ACT-132577, which reaches its peak plasma concentration about 30 hours after the first dose is administered, and has a half-life of approximately 48 hours.^[6] Although ACT-132577 has a lower affinity for the ET receptors than its parent compound,^[2] it does have higher plasma concentrations than macitentan.^[6] Both compounds can be excreted from the body through the urine or feces.^[5]

Co-administration of ciclosporin has only a slight effect on the concentrations of macitentan and its active metabolite, while rifampicin decreases the area under the curve (AUC) of the drug's blood plasma concentration by 79%, and ketoconazole approximately doubles it. This corresponds to the finding that macitentan is mainly metabolised via the liver enzyme CYP3A4.^[7]

File:ACT-132577 skeletal.svg

ACT-132577, the active metabolite of macitentan

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References

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 Hong, I.S., Coe, H.V., & Catanzaro, L.M. (2014). Macitentan for the treatment of pulmonary arterial hypertension. The Annals of Pharmacotherapy, 48, 1-10.
↑ ^2.0 ^2.1 Iglarz, M., Qiu, C., Fischli, W., Morrison, K., Binkert, C., Clozel, M., Hess, P., Capeleto, B., Buchmann, S., Boss, C., Bolli, M.H., Weller, T., Treiber, A., & Gatfield, J. (2008). Pharmacology of macitentan, an orally active tissue-targeting dual endothelin receptor antagonist. Journal of Pharmacology and Experimental Therapeutics, 327(3), 736-745.
↑ Actelion receives us fda approval of Opsumit (macitentan) for the treatment of pulmonary arterial hypertension. Actelion. Retrieved 22 October 2013.
↑ ^4.00 ^4.01 ^4.02 ^4.03 ^4.04 ^4.05 ^4.06 ^4.07 ^4.08 ^4.09 ^4.10 ^4.11 Gatfield, J., Grandjean, C. M., Sasse, T., Clozel, M., & Nayler, O. (2012). Slow receptor dissociation kinetics differentiate macitentan from other endothelin receptor antagonists in pulmonary arterial smooth muscle cells. PLoS ONE, 7(10), e47662.
↑ ^5.0 ^5.1 Bruderer, S., Hopfgartner, G., Seiberling, M., Wank, J., Sidharta, P.N., Treiber, A., & Dingemanse, J. (2012). Absorption, distribution, metabolism, and excretion of macitentan, a dual endothelin receptor antagonist, in humans. Xenobiotica, 42(9), 901-910.
↑ ^6.0 ^6.1 ^6.2 Sidharta, P.N., van Giersbergen, P.L., Halabi, A., & Dingemanse, J. (2011). Macitentan: entry-into-humans study with a new endothelin receptor antagonist. Eur J Clin Pharmacol, 67, 977–984.
↑ PMID 22189899 (PMID 22189899)
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External links

Actelion home page

Template:PAH rx

Template:Cardiovascular-drug-stub

[(3)-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 Hong, I.S., Coe, H.V., & Catanzaro, L.M. (2014). Macitentan for the treatment of pulmonary arterial hypertension. The Annals of Pharmacotherapy, 48, 1-10.

[(4)-2] 2.0 ^2.1 Iglarz, M., Qiu, C., Fischli, W., Morrison, K., Binkert, C., Clozel, M., Hess, P., Capeleto, B., Buchmann, S., Boss, C., Bolli, M.H., Weller, T., Treiber, A., & Gatfield, J. (2008). Pharmacology of macitentan, an orally active tissue-targeting dual endothelin receptor antagonist. Journal of Pharmacology and Experimental Therapeutics, 327(3), 736-745.

[3] Actelion receives us fda approval of Opsumit (macitentan) for the treatment of pulmonary arterial hypertension. Actelion. Retrieved 22 October 2013.

[(2)-4] 4.00 ^4.01 ^4.02 ^4.03 ^4.04 ^4.05 ^4.06 ^4.07 ^4.08 ^4.09 ^4.10 ^4.11 Gatfield, J., Grandjean, C. M., Sasse, T., Clozel, M., & Nayler, O. (2012). Slow receptor dissociation kinetics differentiate macitentan from other endothelin receptor antagonists in pulmonary arterial smooth muscle cells. PLoS ONE, 7(10), e47662.

[(1)-5] 5.0 ^5.1 Bruderer, S., Hopfgartner, G., Seiberling, M., Wank, J., Sidharta, P.N., Treiber, A., & Dingemanse, J. (2012). Absorption, distribution, metabolism, and excretion of macitentan, a dual endothelin receptor antagonist, in humans. Xenobiotica, 42(9), 901-910.

[(5)-6] 6.0 ^6.1 ^6.2 Sidharta, P.N., van Giersbergen, P.L., Halabi, A., & Dingemanse, J. (2011). Macitentan: entry-into-humans study with a new endothelin receptor antagonist. Eur J Clin Pharmacol, 67, 977–984.

[7] PMID 22189899 (PMID 22189899)
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