Rofecoxib [Vioxx, MK-0966; 4-(4'-methylsulfonylphenyl)-3-phenyl-2-(5H)-furanone]: a potent and orally active cyclooxygenase-2 inhibitor. Pharmacological and biochemical profiles.
The discoveries that cyclooxygenase (COX)-2 is an inducible form of COX involved in inflammation and that COX-1 is the major isoform responsible for the production of prostaglandins (PGs) in the gastrointestinal tract have provided a rationale for the development of specific COX-2 inhibitors as a new class of anti-inflammatory agents with improved gastrointestinal tolerability. In the present study, the preclinical pharmacological and biochemical profiles of rofecoxib [Vioxx, also known as MK-0966, 4-(4'-methylsulfonylphenyl)-3-phenyl-2-(5H)-furanone], an orally active COX-2 inhibitor, are described. Rofecoxib is a potent inhibitor of the COX-2-dependent production of PGE(2) in human osteosarcoma cells (IC(50) = 26 +/- 10 nM) and Chinese hamster ovary cells expressing human COX-2 (IC(50) = 18 +/- 7 nM) with a 1000-fold selectivity for the inhibition of COX-2 compared with the inhibition of COX-1 activity (IC(50) > 50 microM in U937 cells and IC(50) > 15 microM in Chinese hamster ovary cells expressing human COX-1). Rofecoxib is a time-dependent inhibitor of purified human recombinant COX-2 (IC(50) = 0.34 microM) but caused inhibition of purified human COX-1 in a non-time-dependent manner that could only be observed at a very low substrate concentration (IC(50) = 26 microM at 0.1 microM arachidonic acid concentration). In an in vitro human whole blood assay, rofecoxib selectively inhibited lipopolysaccharide-induced, COX-2-derived PGE(2) synthesis with an IC(50) value of 0.53 +/- 0.02 microM compared with an IC(50) value of 18.8 +/- 0.9 microM for the inhibition of COX-1-derived thromboxane B(2) synthesis after blood coagulation. Using the ratio of the COX-1 IC(50) values over the COX-2 IC(50) values in the human whole blood assay, selectivity ratios for the inhibition of COX-2 of 36, 6.6, 2, 3, and 0.4 were obtained for rofecoxib, celecoxib, meloxicam, diclofenac, and indomethacin, respectively. In several in vivo rodent models, rofecoxib is a potent inhibitor of carrageenan-induced paw edema (ID(50) = 1.5 mg/kg), carrageenan-induced paw hyperalgesia (ID(50) = 1.0 mg/kg), lipopolysaccharide-induced pyresis (ID(50) = 0.24 mg/kg), and adjuvant-induced arthritis (ID(50) = 0.74 mg/kg/day). Rofecoxib also has a protective effect on adjuvant-induced destruction of cartilage and bone structures in rats. In a (51)Cr excretion assay for detection of gastrointestinal integrity in either rats or squirrel monkeys, rofecoxib has no effect at doses up to 200 mg/kg/day for 5 days. Rofecoxib is a novel COX-2 inhibitor with a biochemical and pharmacological profile clearly distinct from that of current nonsteroidal anti-inflammatory drugs and represents a new therapeutic class of anti-inflammatory agents for the treatment of the symptoms of osteoarthritis and rheumatoid arthritis with improved gastrointestinal tolerability.
Chan
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CC
Departments of Pharmacology, Biochemistry and Molecular Biology, and Medicinal Chemistry, Merck Frosst Centre for Therapeutic Research, Kirkland, Quebec, Canada. chi_chung_chan@merck.com
Boyce
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Brideau
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Charleson
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Cromlish
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Ethier
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D
Evans
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Ford-Hutchinson
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Forrest
M J
MJ
Gauthier
J Y
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Gordon
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Gresser
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Guay
J
J
Kargman
S
S
Kennedy
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B
Leblanc
Y
Y
Leger
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Mancini
J
J
O'Neill
G P
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Ouellet
M
M
Patrick
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Percival
M D
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Perrier
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Prasit
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Rodger
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D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000378:metabolism; D000818:Animals; D001093:Arachidonate 15-Lipoxygenase / Q000378:metabolism; D016718:Arachidonic Acid / Q000378:metabolism; D001169:Arthritis, Experimental / Q000097:blood / Q000378:metabolism; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology; D019556:COS Cells; D002460:Cell Line; D006224:Cricetinae; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D004064:Digestive System / Q000187:drug effects; D004285:Dogs; D004487:Edema / Q000139:chemically induced / Q000517:prevention & control; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000139:chemically induced / Q000517:prevention & control; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism*; D007783:Lactones / Q000494:pharmacology*; D007975:Leukotriene B4 / Q000096:biosynthesis; D008297:Male; D008565:Membrane Proteins; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D051381:Rats; D011917:Rats, Inbred Lew; D012453:Saimiri; D013450:Sulfones
D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D007783:Lactones; D008565:Membrane Proteins; D013450:Sulfones; C116926:rofecoxib; D007975:Leukotriene B4; D016718:Arachidonic Acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D001093:Arachidonate 15-Lipoxygenase; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases