A novel thienylhydrazone, (2-thienylidene)3,4-methylenedioxybenzoylhydrazine, increases inotropism and decreases fatigue of skeletal muscle

We report here the preclinical profile of etoricoxib (MK-0663) [5-chloro-2-(6-methylpyridin-3-yl)-3-(4-methylsulfonylphenyl) pyridine], a novel orally active agent that selectively inhibits cyclooxygenase-2 (COX-2), that has been developed for high selectivity in vitro using whole blood assays and sensitive COX-1 enzyme assays at low substrate concentration. Etoricoxib selectively inhibited COX-2 in human whole blood assays in vitro, with an IC(50) value of 1.1 +/- 0.1 microM for COX-2 (LPS-induced prostaglandin E2 synthesis), compared with an IC(50) value of 116 +/- 8 microM for COX-1 (serum thromboxane B2 generation after clotting of the blood). Using the ratio of IC(50) values (COX-1/COX-2), the selectivity ratio for the inhibition of COX-2 by etoricoxib in the human whole blood assay was 106, compared with values of 35, 30, 7.6, 7.3, 2.4, and 2.0 for rofecoxib, valdecoxib, celecoxib, nimesulide, etodolac, and meloxicam, respectively. Etoricoxib did not inhibit platelet or human recombinant COX-1 under most assay conditions (IC(50) > 100 microM). In a highly sensitive assay for COX-1 with U937 microsomes where the arachidonic acid concentration was lowered to 0.1 microM, IC(50) values of 12, 2, 0.25, and 0.05 microM were obtained for etoricoxib, rofecoxib, valdecoxib, and celecoxib, respectively. These differences in potency were in agreement with the dissociation constants (K(i)) for binding to COX-1 as estimated from an assay based on the ability of the compounds to delay the time-dependent inhibition by indomethacin. Etoricoxib was a potent inhibitor in models of carrageenan-induced paw edema (ID(50) = 0.64 mg/kg), carrageenan-induced paw hyperalgesia (ID(50) = 0.34 mg/kg), LPS-induced pyresis (ID(50) = 0.88 mg/kg), and adjuvant-induced arthritis (ID(50) = 0.6 mg/kg/day) in rats, without effects on gastrointestinal permeability up to a dose of 200 mg/kg/day for 10 days. In squirrel monkeys, etoricoxib reversed LPS-induced pyresis by 81% within 2 h of administration at a dose of 3 mg/kg and showed no effect in a fecal 51Cr excretion model of gastropathy at 100 mg/kg/day for 5 days, in contrast to lower doses of diclofenac or naproxen. In summary, etoricoxib represents a novel agent that selectively inhibits COX-2 with 106-fold selectivity in human whole blood assays in vitro and with the lowest potency of inhibition of COX-1 compared with other reported selective agents.     

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.     

ABT-963 [2-(3,4-difluoro-phenyl)-4-(3-hydroxy-3-methyl-butoxy)-5-(4-methanesulfonyl-phenyl)-2H-pyridazin-3-one], a highly potent and selective disubstituted pyridazinone cyclooxgenase-2 inhibitor

Nonsteriodal anti-inflammatory drugs (NSAIDs) are efficacious for the treatment of pain associated with inflammatory disease. Clinical experience with marketed selective cyclooxygenase-2 (COX-2) inhibitors (celecoxib, rofecoxib, and valdecoxib) has confirmed the utility of these agents in the treatment of inflammatory pain with an improved gastrointestinal safety profile relative to NSAID comparators. These COX-2 inhibitors belong to the same structural class. Each contains a core heterocyclic ring with two appropriately substituted phenyl rings appended to adjacent atoms. Here, we report the identification of vicinally disubstituted pyridazinones as potent and selective COX-2 inhibitors. The lead compound in the series, ABT-963 [2-(3,4-difluoro-phenyl)-4-(3-hydroxy-3-methyl-butoxy)-5-(4-methanesulfonyl-phenyl)-2H-pyridazin-3-one], has excellent selectivity (ratio of 276, COX-2/COX-1) in human whole blood, improved aqueous solubility compared with celecoxib and rofecoxib, high oral anti-inflammatory potency in vivo, and gastric safety in the animal studies. After oral administration, ABT-963 reduced prostaglandin E2 production in the rat carrageenan air pouch model (ED50 of 0.4 mg/kg) and reduced the edema in the carrageenan induced paw edema model with an ED30 of 1.9 mg/kg. ABT-963 dose dependently reduced nociception in the carrageenan hyperalgesia model (ED50 of 3.1 mg/kg). After 14 days of dosing in the adjuvant arthritis model, ABT-963 had an ED(50) of 1.0 mg/kg in reducing the swelling of the hind paws. Magnetic resonance imaging examination of the diseased paws in the adjuvant model showed that ABT-963 significantly reduced bone loss and soft tissue destruction. ABT-963 is a highly selective COX-2 inhibitor that may have utility in the treatment of the pain and inflammation associated with arthritis.     

The cyclooxygenase-2 inhibitor GW406381X [2-(4-ethoxyphenyl)-3-[4-(methylsulfonyl)phenyl]-pyrazolo[1,5-b]pyridazine] is effective in animal models of neuropathic pain and central sensitization

The pathogenic form of the cyclooxygenase (COX) enzyme, COX-2, is also constitutively present in the spinal cord and has been implicated in chronic pain states in rat and man. A number of COX-2 inhibitors, including celecoxib and rofecoxib, are already used in man for the treatment of inflammatory pain. Preclinically, the dual-acting COX-2 inhibitor, GW406381X [2-(4-ethoxyphenyl)-3-[4-(methylsulfonyl)phenyl]-pyrazolo[1,5-b]pyridazine, where X denotes the free base], is as effective as rofecoxib and celecoxib in the rat established Freund's Complete Adjuvant model with an ED(50) of 1.5 mg/kg p.o. compared with 1.0 mg/kg p.o. for rofecoxib and 6.6 mg/kg p.o. for celecoxib. However, in contrast to celecoxib (5 mg/kg p.o. b.i.d.) and rofecoxib (5 mg/kg p.o. b.i.d.), which were without significant effect, GW406381X (5 mg/kg p.o. b.i.d.) fully reversed mechanical allodynia in the chronic constriction injury model and reversed thermal hyperalgesia in the mouse partial ligation model, both models of neuropathic pain. GW406381X, was also effective in a rat model of capsaicin-induced central sensitization, when given intrathecally (ED(50) = 0.07 mug) and after chronic but not acute oral dosing. Celecoxib and rofecoxib had no effect in this model. Several hypotheses have been proposed to try to explain these differences in efficacy, including central nervous system penetration, enzyme kinetics, and potency. The novel finding of effectiveness of GW406381X in these models of neuropathic pain/central sensitization, in addition to activity in inflammatory pain models and together with its central efficacy, suggests dual activity of GW406381X compared with celecoxib and rofecoxib, which may translate into greater efficacy in a broader spectrum of pain states in the clinic.     

Valdecoxib is more efficacious than rofecoxib in relieving pain associated with oral surgery

Inhibition of the cyclooxygenase (COX)-2 enzyme has been shown previously to reduce pain and inflammation. Valdecoxib is a new highly selective COX-2 inhibitor with a rapid onset of action and significant analgesic properties. This study compared the analgesic efficacy of valdecoxib and rofecoxib in treating postoperative pain in patients undergoing oral surgery. This randomized, double-blind, placebo-controlled study compared the efficacy of 40 mg valdecoxib with that of 50 mg rofecoxib and placebo. Efficacy was assessed by the onset of analgesia, pain intensity levels, and pain relief over 24 hours, time-weighted sum of total pain, sum of pain intensity difference, the percentage of patients requiring rescue medication and experiencing regimen failure, and patients' global evaluation. Patients receiving valdecoxib experienced a significantly quicker onset of analgesia, significantly improved pain relief, and lower pain intensity compared with patients receiving rofecoxib and greater satisfaction with their study medication after a single dose. Valdecoxib also demonstrated efficacy that was superior to that of rofecoxib with respect to the percentage of patients requiring rescue medication or experiencing regimen failure (p < or =.05). Valdecoxib, rofecoxib, and placebo were equally well tolerated. This study demonstrates that valdecoxib provides significantly greater analgesic efficacy than rofecoxib in the management of pain after oral surgery.     

Nonsteroidal anti-inflammatory drug-activated gene-1 plays a role in the impairing effects of cyclooxygenase inhibitors on gastric ulcer healing

Nonsteroidal anti-inflammatory drugs (NSAIDs) can impair gastric ulcer healing. This study investigates the involvement of NSAID-activated gene-1 (NAG-1) in ulcer repair impairment by cyclooxygenase (COX) inhibitors. Gastric ulcers were induced in rats by acetic acid. Four days later, animals received daily intragastric indomethacin (nonselective COX-1/COX-2 inhibitor; 1 mg/kg), 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazole (SC-560) (selective COX-1 inhibitor; 2.5 mg/kg), (5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulfonyl) phenyl-2(5H)-furanone (DFU) (selective COX-2 inhibitor; 5 mg/kg), celecoxib (selective COX-2 inhibitor; 1 mg/kg), and valdecoxib (selective COX-2 inhibitor; 1 mg/kg), for 1, 3, or 7 days. Ulcerated tissues were processed to assess: 1) COX-1, COX-2, NAG-1, proliferating cell nuclear antigen (PCNA), and activated caspase-3 expression; 2) ulcer area; and 3) prostaglandin E(2) (PGE(2)) levels. COX-1 expression in ulcerated tissues was decreased, whereas COX-2 expression was enhanced. Ulcer healing was delayed by indomethacin, DFU, and SC-560, but not by celecoxib and valdecoxib. Ulcer PGE(2) levels were decreased by SC-560, DFU, celecoxib, valdecoxib, and indomethacin. NAG-1 was overexpressed in ulcerated tissues and further enhanced by indomethacin, DFU, and SC-560, but not by celecoxib or valdecoxib. PCNA expression in ulcerated areas was reduced by indomethacin, but not by the other test drugs. The expression of activated caspase-3 in ulcers was increased and enhanced further by indomethacin, DFU, and SC-560, but not by celecoxib and valdecoxib. These findings indicate that: 1) COX inhibitors exert differential impairing effects on gastric ulcer healing, through mechanisms unrelated to the inhibition of COX isoforms and prostaglandin production; and 2) NAG-1 induction, followed by activation of proapoptotic pathways, can contribute to the impairing effects of COX inhibitors on ulcer healing.     

Development and clinical application of COX-2-selective inhibitors for the treatment of osteoarthritis and rheumatoid arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are among the most prevalent chronic illnesses and leading causes of disability in the United States. The clinical symptoms of OA and RA, pain and inflammation, are biologic processes mediated in part by prostanoids-prostaglandins, prostacyclin, and thromboxanes. The intermediate enzymes responsible for prostaglandin biosynthesis, cyclooxygenase (COX)-1 and COX-2, have been the target of arthritis therapy using nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). An understanding of the biochemistry and molecular pharmacology of COX enzymes has allowed for the development of agents that specifically inhibit COX-2. COX-2-selective inhibitors have efficacy in OA and RA that is similar to that of NSAIDs but with a lower potential for upper gastrointestinal injury, a serious side effect of nonselective NSAIDs. COX-2-selective inhibitors have been increasingly used in the treatment of OA and RA as well as other inflammatory arthropathies including ankylosing spondylitis and gout. Clinical trials with two currently available drugs, rofecoxib and celecoxib, have demonstrated efficacy comparable to nonselective NSAIDs but with a lower risk of gastrointestinal side effects. In general, these drugs are well tolerated in patients with aspirin-sensitive asthma. Rofecoxib is well tolerated in patients with sulfonamide sensitivities; further studies are needed to fully characterize the utility of celecoxib in these patients. Clinical experience shows that because of their improved GI safety, rofecoxib and celecoxib, and newer COX-2-selective inhibitors (valdecoxib, etoricoxib, parecoxib), represent a significant advance in the treatment of arthritis and other related inflammatory conditions.     

Valdecoxib versus rofecoxib in acute postsurgical pain: results of a randomized controlled trial

The analgesic efficacy of the cyclooxygenase-2 specific inhibitors, valdecoxib and rofecoxib, were evaluated in patients following oral surgery. In a randomized, double-blind, controlled trial, patients experiencing moderate or severe pain received single-dose valdecoxib 40 mg (n=99), rofecoxib 50 mg (n=101), or placebo (n=50) within 4 hours after multiple third molar extraction with bone removal. Onset of action was significantly faster with valdecoxib 40 mg (30 minutes) compared with rofecoxib 50 mg (45 minutes), as measured by pain intensity difference and pain relief scores (P 相似文献   

Intravenous parecoxib rapidly leads to COX-2 inhibitory concentration of valdecoxib in the central nervous system

Evidence in animal studies supports widespread induction of cyclooxygenase-2 (COX-2) in the central nervous system (CNS) following tissue injury, probably mediated by cytokines, transducing the signal across the blood-brain barrier. CNS COX-2 blockade is a possible therapeutic target for drugs that are able to reach adequate CNS levels and abolish the prostaglandin E2-induced central sensitization. This human pharmacokinetic study investigated valdecoxib cerebrospinal fluid (CSF) and plasma concentrations over time in 37 patients following 40 mg of single-dose intravenous parecoxib. High-performance liquid chromatography/tandem mass spectrometry analysis was performed. Valdecoxib was first detectable in the CSF at 15 min postdosing, increased rapidly until 50 min, and thereafter remained between 6 and 14 ng/ml. This is the first human study demonstrating CNS COX-2 inhibitor penetration as early as 15 min. CSF valdecoxib concentration rapidly reached in vitro IC50 (inhibitory concentration 50) (1.57 ng/ml) by 17 min and remained consistently higher thereafter.     

Characterization of rofecoxib as a cyclooxygenase-2 isoform inhibitor and demonstration of analgesia in the dental pain model

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, and indomethacin (INN, indometacin) inhibit both the constitutive (COX-1) and inducible (COX-2) isoforms of cyclooxygenase. The induction of COX-2 after inflammatory stimuli has led to the hypothesis that COX-2 inhibition primarily accounts for the therapeutic properties of NSAIDs. METHODS: Chinese hamster ovary (CHO) cell lines that express each COX isoform were used to characterize the in vitro selectivity of rofecoxib. Single oral doses of rofecoxib and indomethacin were then assessed in subjects with use of ex vivo COX-isoform specific assays (serum thromboxane B2 [TXB2] and lipopolysaccharide [LPS]-stimulated whole blood prostaglandin E2 and assays of COX-1 and COX-2 activity, respectively). A double-blind, parallel-group study compared the analgesic efficacy of rofecoxib to placebo and ibuprofen in 102 patients with dental pain. RESULTS: Rofecoxib showed a >800-fold COX-2 selectivity with use of CHO cells that express human COX-1 and COX-2. In subjects, dose- and concentration-dependent inhibition of LPS-stimulated prostaglandin E2 was observed with both rofecoxib (IC50 [the concentration estimated to produce 50% inhibition], 0.77 micromol/L) and indomethacin (IC50, 0.33 micromol/L). Whereas indomethacin inhibited TXB2, (IC50, 0.14 micromol/L), no inhibition was observed with rofecoxib even at doses of up to 1000 mg. In the dental pain study, total pain relief (TOTPAR) over the 6 hours after dosing was similar between 50 mg and 500 mg rofecoxib and 400 mg ibuprofen (P > .20). All active treatments showed greater improvement than placebo (P < .001) CONCLUSIONS: Rofecoxib inhibited COX-2 without evidence of COX-1 inhibition, even at oral doses of up to 1000 mg. Nonetheless, rofecoxib showed analgesic activity indistinguishable from that observed with ibuprofen, a nonisoform-selective COX inhibitor. These results support the hypothesis that the analgesic effects of NSAIDs primarily derive from inhibition of COX-2.     

Interactions between aspirin and COX-2 inhibitors or NSAIDs in a rat thrombosis model

Recent in vitro studies, clinical trials and epidemiological studies have suggested possible interactions between aspirin and other cyclo-oxygenase (COX) inhibitors, such as ibuprofen of the COX-2 inhibitors celecoxib and rofecoxib. The objective of this study was to test the effects of aspirin (1, 2.5 and 5 mg/kg), and ibuprofen (4 and 15 mg/kg), diclofenac (2.5 mg/kg), flurbiprofen (2 mg/kg), celecoxib (7.5 mg/kg), and rofecoxib (1 mg/kg), alone or combined on a rat model of arterial thrombosis. Drugs were given orally daily for 7 days, before insertion of an arterio-venous shunt thrombosis system, left in place for 15 min. Main parameter was thrombus weight. Five to 12 rats were used per experiment, and 35 controls overall. Aspirin inhibited thrombus formation in a dose-dependent manner. All NSAIDS given alone also inhibited thrombus formation to approximately the same level as aspirin 1 mg/kg/day. Ibuprofen, celecoxib and rofecoxib inhibited the effects of aspirin, but not diclofenac or flurbiprofen. The interactions with aspirin do not seem to affect all NSAIDs to equal levels. The clinical impact of this needs to be confirmed in adequately powered clinical trials or pharmaco-epidemiological studies.     

Valdecoxib: a review

BACKGROUND: Traditional nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac, ibuprofen, naproxen, and related agents are nonselective inhibitors of both cyclooxygenase-1 (COX-1) and COX-2, which catalyze prostaglandin synthesis. This inhibition accounts not only for the analgesic, anti-inflammatory, and antipyretic effects of these agents, but also for side effects such as gastric mucosal damage and renal toxicity. Substantial evidence suggests that sparing COX-1 is advantageous for gastric safety. OBJECTIVE: This article reviews available information on the new COX-2-selective inhibitor valdecoxib, including its clinical pharmacology, pharmacokinetics, adverse effects, potential drug interactions, and contraindications and warnings. Results of clinical trials of efficacy and tolerability are summarized. METHODS: Articles for inclusion in this review were identified through searches of PubMed and MEDLINE (1966-December 2002) and International Pharmaceutical Abstracts (1970-December 2002). Search terms included valdecoxib, Bextra, COX-2-selective inhibitors, coxibs, and selective cyclooxygenase inhibitors. The reference lists of identified articles were reviewed for additional publications. Product information was also obtained from the manufacturer of valdecoxib. RESULTS: Fourteen clinical studies involving > 4000 patients have been conducted. Valdecoxib was significantly more effective than placebo in the treatment of adult rheumatoid arthritis, osteoarthritis, pain associated with primary dysmenorrhea, and postoperative pain. Valdecoxib was comparable to naproxen for the treatment of rheumatoid arthritis in 1 study and equivalent to naproxen for the treatment of osteoarthritis in other studies. Three studies found valdecoxib comparable to naproxen sodium for the relief of moderate to severe pain due to primary dysmenorrhea, and others found valdecoxib comparable to oxycodone plus acetaminophen and significantly more effective than rofecoxib for the relief of pain associated with dental surgery (P < 0.05). Four safety studies and 2 reviews of clinical trials documented lower rates of endoscopic gastroduodenal ulcer formation with valdecoxib compared with ibuprofen, naproxen, and diclofenac (P < 0.001 to P < 0.05). Valdecoxib did not inhibit platelet function (bleeding time and platelet aggregation) in healthy adults or in the elderly. Due to the risk of potentially serious skin and allergic reactions, patients who are allergic to sulfa-containing drugs should not take valdecoxib. The drug should be discontinued immediately if rash develops. CONCLUSIONS: In clinical trials, valdecoxib was effective for the treatment of osteoarthritis, rheumatoid arthritis, and moderate to severe pain associated with primary dysmenorrhea. As with the other COX-2-selective inhibitors (celecoxib and rofecoxib), valdecoxib appears to produce less gastrointestinal toxicity than conventional nonselective NSAIDs, although some of the relevant clinical studies have been published only as abstracts. Use of valdecoxib should be reserved for patients at risk for NSAID-induced gastrointestinal problems.     

In vitro and in vivo pharmacological characterization of BM-613 [N-n-pentyl-N'-[2-(4'-methylphenylamino)-5-nitrobenzenesulfonyl]urea], a novel dual thromboxane synthase inhibitor and thromboxane receptor antagonist

Thromboxane A2 (TXA2) is a key mediator of platelet aggregation and smooth muscle contraction. Its action is mediated by its G protein-coupled receptor of which two isoforms, termed TPalpha and TPbeta, occur in humans. TXA2 has been implicated in pathologies such as cardiovascular diseases, pulmonary embolism, atherosclerosis, and asthma. This study describes the pharmacological characterization of BM-613 [N-n-pentyl-N'-[2-(4'-methylphenylamino)-5-nitrobenzenesulfonyl]urea], a new combined TXA2 receptor antagonist and TXA2 synthase inhibitor. It exhibits a strong affinity for human platelet TP receptors (IC50 = 1.4 nM), TPalpha and TPbeta expressed in COS-7 cells (IC(50) = 2.1 and 3.1 nM, respectively), and TPs expressed in human coronary artery smooth muscle cells (IC50 = 29 microM). BM-613 shows a weak ability to prevent contraction of isolated rat aorta (ED50 = 1.52 microM) and guinea pig trachea (ED50 = 2.5 microM) induced by TXA2 agonist U-46619 (9.11-dideoxy-9.11-methanoepoxy-prostaglandin F2). Besides, BM-613 antagonizes TPalpha (IC50 = 0.11 microM) and TPbeta (IC50 = 0.17 microM) calcium mobilization induced by U-46619 and inhibits human platelet aggregation induced by U-46619 (ED50 = 0.278 microM), arachidonic acid (ED50 = 0.375 microM), and the second wave of ADP. BM-613 also dose dependently prevents TXA2 production by human platelets (IC50 = 0.15 microM). In a rat model of ferric chloride-induced thrombosis, BM-613 significantly reduces weight of formed thrombus by 79, 49, and 28% at 5, 2, and 1 mg/kg i.v., respectively. In conclusion, BM-613 is a dual and potent TP receptor antagonist and TXA2 synthase inhibitor characterized by a strong antiplatelet and antithrombotic potency. These results suggest that BM-613 could be a potential therapeutic drug for thrombotic disorders.     

Pharmacological characterization of LY233053: a structurally novel tetrazole-substituted competitive N-methyl-D-aspartic acid antagonist with a short duration of action

This study reports the activity of a structurally novel excitatory amino acid receptor antagonist, LY233053 [cis-(+-)-4-[(2H-tetrazol-5-yl)methyl]piperidine-2-carboxylic acid], the first tetrazole-containing competitive N-methyl-D-aspartic acid (NMDA) antagonist. LY233053 potently inhibited NMDA receptor binding to rat brain membranes as shown by the in vitro displacement of [3H] CGS19755 (IC50 = 107 +/- 7 nM). No appreciable affinity in [3H]alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) or [3H]kainate binding assays was observed (IC50 values greater than 10,000 nM). In vitro NMDA receptor antagonist activity was further demonstrated by selective inhibition of NMDA-induced depolarization in cortical wedges (IC50 = 4.2 +/- 0.4 microM vs. 40 microM NMDA). LY233053 was effective after in vivo systemic administration in a number of animal models. In neonatal rats, LY233053 selectively blocked NMDA-induced convulsions (ED50 = 14.5 mg/kg i.p.) with a relatively short duration of action (2-4 hr). In pigeons, LY233053 potently antagonized (ED50 = 1.3 mg/kg i.m.) the behavioral suppressant effects of 10 mg/kg of NMDA. However, a dose of 160 mg/kg, i.m., was required to produce phencyclidine-like catalepsy in pigeons. In mice, LY233053 protected against maximal electroshock-induced seizures at lower doses (ED50 = 19.9 mg/kg i.p.) than those that impaired horizontal screen performance (ED50 = 40.9 mg/kg i.p.). Cholinergic and GABAergic neuronal degenerations after striatal infusion of NMDA were prevented by single or multiple i.p. doses of LY233053. In summary, the antagonist activity of LY233053 after systemic administration demonstrates potential therapeutic value in conditions of neuronal cell loss due to NMDA receptor excitotoxicity. The relatively short duration of action of LY233053 may make this compound particularly advantageous as a neuroprotective agent in the treatment of acute conditions such as cerebral ischemia.     

Pharmacological characterization of KLYP961, a dual inhibitor of inducible and neuronal nitric-oxide synthases

Nitric oxide (NO) derived from neuronal nitric-oxide synthase (nNOS) and inducible nitric-oxide synthase (iNOS) plays a key role in various pain and inflammatory states. KLYP961 (4-((2-cyclobutyl-1H-imidazo[4,5-b]pyrazin-1-yl)methyl)-7,8-difluoroquinolin-2(1H)-one) inhibits the dimerization, and hence the enzymatic activity of human, primate, and murine iNOS and nNOS (IC(50) values 50-400 nM), with marked selectivity against endothelial nitric-oxide synthase (IC(50) >15,000 nM). It has ideal drug like-properties, including excellent rodent and primate pharmacokinetics coupled with a minimal off-target activity profile. In mice, KLYP961 attenuated endotoxin-evoked increases in plasma nitrates, a surrogate marker of iNOS activity in vivo, in a sustained manner (ED(50) 1 mg/kg p.o.). KLYP961 attenuated pain behaviors in a mouse formalin model (ED(50) 13 mg/kg p.o.), cold allodynia in the chronic constriction injury model (ED(50) 25 mg/kg p.o.), or tactile allodynia in the spinal nerve ligation model (ED(50) 30 mg/kg p.o.) with similar efficacy, but superior potency relative to gabapentin, pregabalin, or duloxetine. Unlike morphine, the antiallodynic activity of KLYP961 did not diminish upon repeated dosing. KLYP961 also attenuated carrageenin-induced edema and inflammatory hyperalgesia and writhing response elicited by phenylbenzoquinone with efficacy and potency similar to those of celecoxib. In contrast to gabapentin, KLYP961 did not impair motor coordination at doses as high as 1000 mg/kg p.o. KLYP961 also attenuated capsaicin-induced thermal allodynia in rhesus primates in a dose-related manner with a minimal effective dose (≤ 10 mg/kg p.o.) and a greater potency than gabapentin. In summary, KLYP961 represents an ideal tool with which to probe the physiological role of NO derived from iNOS and nNOS in human pain and inflammatory states.     

Renal effects of etoricoxib and comparator nonsteroidal anti-inflammatory drugs in controlled clinical trials

BACKGROUND: Based on the experience with selective cyclooxygenase (COX)-2 inhibitors, including rofecoxib, valdecoxib, and celecoxib, it was anticipated that etoricoxib, a new selective COX-2 inhibitor, would display mechanism-based, dose-dependent renal adverse effects (AEs) similar to those observed with nonselective non-steroidal anti-inflammatory drugs (NSAIDs) in long-term treatment. OBJECTIVE: The present analysis examined pooled safety data from the etoricoxib clinical development program with the aim of comparing the renal AE profiles of etoricoxib 60, 90, and 120 mg/d with those of approved therapeutic dosages of the comparator nonselective NSAIDs, naproxen 1000 mg/d and ibuprofen 2400 mg/d, and with that of placebo. METHODS: The etoricoxib program database included data from 8 placebo-controlled Phase III studies of osteoarthritis, rheumatoid arthritis, and chronic low back pain. As part of the program-wide assessment of etoricoxib, the investigator-reported incidence of and discontinuations due to renal AEs, including hypertension, lower-extremity edema (LEE), elevated serum creatinine concentration (SCC), and congestive heart failure (CHF) were examined. RESULTS: Data from 4770 patients were included in the analysis. Most patients were women (69.0%-80.3%), and most were white (68.0%-83.3%). The mean (SD) age at baseline ranged from 53.6 (12.1) to 62.2 (8.4) years. Overall, the incidence of renal AEs was low and generally similar between the active-treatment groups. In the placebo; etoricoxib 60-, 90-, and 120-mg; naproxen, and ibuprofen groups, the incidences of hypertension were 2.0%, 4.0%, 3.4%, 4.7%, 2.9%, and 6.6%, respectively, and the incidences of LEE were 1.9%, 3.2%, 1.5%, 1.3%, 2.3%, and 1.8%, respectively. The only significant difference found was the incidence of hypertension with etoricoxib 90 mg/d versus that with placebo (P=0.001); however, the rates of hypertension observed with etoricoxib at any dosage were not clinically meaningfully different versus comparator NSAIDs. Also, LEE was rarely of clinical significance with etoricoxib or comparator NSAIDs; related discontinuations were infrequent in all treatment groups. In addition, the incidences of elevated SCC and CHF were low among active-treatment groups (0.0% to 0.8% and 0.0% to 0.2%, respectively). CONCLUSIONS: Based on this combined data review, the risks for renal AEs (i.e., hypertension, LEE, elevated SCC changes, and CHF) with etoricoxib 60, 90, and 120 mg/d were low, with a shallow dose response, and were generally similar to those found with the comparator NSAIDs naproxen 1000 mg/d and ibuprofen 2400 mg/d.     

Rofecoxib 50 mg and valdecoxib 20 or 40 mg in adults and adolescents with postoperative pain after third molar extraction: results of two randomized, double-blind, placebo-controlled, single-dose studies

OBJECTIVE: These studies assessed the comparative efficacy of rofecoxib and valdecoxib in the treatment of acute postoperative dental pain. METHODS: Two randomized, double-blind, placebo-controlled, single-dose studies were conducted in patients undergoing extraction of > or =2 third molars, with > or =1 mandibular impaction, who experienced moderate or severe pain after extraction. In study 1, patients were randomized in a 4:4:1 ratio to receive rofecoxib 50 mg, valdecoxib 20 mg, or placebo. In study 2, which was an exploratory study, patients were randomized in a 2:2:1 ratio to receive reofecoxib 50 mg, valdecoxib 40 mg, or palcebo. The primary efficacy end point was total pain relief at 12 hours (TOPAR12) for rofecoxib compared with valdecoxib 20 mg (study 1) or valdecoxib 40 mg (study 2). Tolerability was assessed based on clinical adverse experiences (AEs) and vital signs. These studies were performed before both agents were withdrawn from the market. RESULTS: In study 1, 200 patients were randomized to receive rofecoxib 50 mg, 201 to valdecoxib 20 mg, and 49 to placebo. In study 2, 51 patients were randomized to receive rofecoxib 50 mg, 50 to valdecoxib 40 mg, and 24 to placebo. The majority of patients in both studies were female (approximately 54%) and white ( approximately 66%), with a mean age of approximately 22 years and a mean weight of approximately 75 kg. Most (approximately 58%) patients reported experiencing moderate postoperative pain. In study 1, mean TOPAR12 scores were 30.7 for rofecoxib 50 mg, 28.9 for valdecoxib 20 mg, and 5.5 for placebo; in study 2, TOPAR12 scores were 27.0 for rofecoxib 50 mg, 28.6 for valdecoxib 40 mg, and 6.9 for placebo. In both studies, the active treatments were comparable in terms of the primary end point and were statistically superior to placebo (P<0.001). In study 1, rofecoxib was associated with a longer median time to use of rescue medication compared with valdecoxib 20 mg (>24 hours vs 23 hours 58 minutes; P=0.010) and a significantly smaller proportion of patients using rescue medication over 24 hours (35.0% vs 50.2%; P<0.001). In study 2, there were no significant differences in the median time to use of rescue medication or the proportion of patients using rescue medication between active treatments. There were no significant differences in total pain relief at 4 or 8 hours, patients' global assessment, onset of analgesia, or AEs between active treatments in either study. The incidence of clinical AEs in study 1 was similar for rofecoxib 50 mg, valdecoxib 20 mg, and placebo (39.5%, 36.8%, and 49.0%, respectively). In study 2, AEs occurred significantly less frequently with rofecoxib 50 mg compared with placebo (35.3% vs 70.8%, respectively; P<0.01); there was no significant difference between the rate of AEs with valdecoxib 40 mg (50.0%) and placebo. CONCLUSIONS: Rofecoxib 50 mg had comparable analgesic efficacy to valdecoxib 20 and 40 mg in these patients with pain after dental surgery. All active treatments were well tolerated.     

5-lipoxygenase inhibitory activity of zileuton.

Zileuton [N-(1-benzo[b]thien-2-ylethyl)-N-hydroxyure] inhibited 5-hydroxyeicosatetraenoic acid synthesis by rat basophilic leukemia cell 20,000 x g supernatant and rat polymorphonuclear leukocytes (PMNL) (IC50 = 0.5 and 0.3 microM) respectively. It also inhibited leukotriene (LT)B4 biosynthesis by rat PMNL (IC50 = 0.4 microM), human PMNL (IC50 = 0.4 microM) and human whole blood (IC50 = 0.9 microM). Inhibition of human PMNL LTB4 biosynthesis was removed readily by a simple wash procedure. At concentrations up to 100 microM, the compound produced little or no inhibition of several related enzymes, such as platelet 12-lipoxygenase, soybean and rabbit reticulocyte 15-lipoxygenase and sheep seminal vesicle cyclooxygenase. At p.o. doses from 0.5 to 5 mg/kg in the dog, zileuton produced a rapid and sustained inhibition of ex vivo blood LTB4 biosynthesis which correlated with the pharmacokinetic behavior of the compound. In a similar ex vivo study in the rat, the compound displayed an p.o. ED50 of 2 mg/kg. Zileuton was highly effective in preventing 6-sulfidopeptide LT formation in the rat peritoneal cavity triggered by an antigen-antibody reaction with an ED50 of 3 mg/kg. In experimental models of inflammation, zileuton significantly reduced arachidonic-acid induced mouse ear edema (ED50 = 31 mg/kg) and also attenuated inflammatory cell accumulation in the rat pleural Arthus reaction. The effectiveness of this compound for preventing LT formation in vitro, ex vivo and in vivo suggests its utility for preventing the pathophysiological effects of the LTs and other 5-lipoxygenase products in animals and in humans.     

Comparison of rofecoxib,celecoxib, and naproxen on renal function in elderly subjects receiving a normal-salt diet

BACKGROUND: This study compared directly the renal effects of two selective cyclooxygenase (COX)-2 inhibitors (rofecoxib and celecoxib) with naproxen (dual COX-1/COX-2 inhibitor) and placebo in healthy elderly subjects on a sodium-replete diet. METHODS: A total of 67 elderly subjects stabilized in the clinic for weight and urinary sodium on a controlled 200-mEq sodium diet were randomized in a double-blind fashion to receive rofecoxib, 25 mg daily (n = 17); celecoxib, 200 mg twice daily (n = 17); naproxen, 500 mg twice daily (n = 17); or matching placebo (n = 16) for 28 days. Subjects were sequestered in the clinic for the first 14 treatment days on the controlled diet. RESULTS: Daily urinary sodium excretion during the first 72 hours of treatment (primary endpoint) significantly decreased in rofecoxib, celecoxib, and naproxen groups compared with baseline (P < or =.05). Rofecoxib and celecoxib decreases in urinary sodium excretion rates that were comparable with each other, on the basis of predefined boundaries (-39.5 versus -27.1 mEq/d, respectively) and to naproxen (-40.6, mEq/d). Rofecoxib, celecoxib, and naproxen increased mean systolic blood pressure to a similar degree (3.4, 4.3, and 3.1 mm Hg, respectively, versus -1.3 mm Hg for placebo) after 14 days of treatment; small changes also occurred in diastolic blood pressure (0.3, 0.8, and -0.4 mm Hg, respectively, versus -1.4 mm Hg for placebo). Changes from baseline in creatinine clearance, body weight, and urinary potassium excretion among active treatments were similar. After 28 days of treatment, findings were generally consistent with those at 14 days. No subject reported edema or discontinued treatment as the result of an adverse experience. CONCLUSION: In healthy elderly subjects on a sodium-replete diet, the COX-2 inhibitors rofecoxib and celecoxib did not differ from a nonselective nonsteroidal anti-inflammatory drug (naproxen), in influencing renal function as measured by urinary sodium excretion, systolic and diastolic blood pressure, creatinine clearance, or weight change.