Argatroban is a synthetic direct thrombin inhibitor derived from L-arginine. Argatroban is a direct thrombin inhibitor that reversibly binds to the thrombin active site. Argatroban does not require the co-factor antithrombin III for antithrombotic activity. Argatroban exerts its anticoagulant effects by inhibiting thrombin-catalyzed or -induced reactions, including fibrin formation; activation of coagulation factors V, VIII, and XIII; protein C; and platelet aggregation. Argatroban is highly selective for thrombin with an inhibitory constant (Ki) of 0.04 µM. At therapeutic concentrations, Argatroban has little or no effect on related serine proteases (trypsin, factor Xa, plasmin, and kallikrein). Argatroban is capable of inhibiting the action of both free and clot-associated thrombin. Argatroban is indicated as an anticoagulant for prophylaxis or treatment of thrombosis in patients with heparin-induced thrombocytopenia. Argatroban is indicated as an anticoagulant in patients with or at risk for heparin-induced thrombocytopenia undergoing percutaneous coronary intervention (PCI).

Furegrelate (previously known as U-63557A), a selective orally active thromboxane synthase inhibitor, with potential for the treatment of various diseases including hypertension, thrombosis, and renal disorders, arrhythmias, but these studies were discontinued.

AZD-6482 is being developed by AstraZeneca to evaluate its therapeutic effects in the treatment of thrombosis. AZD-6482 is essentially a PI3K-beta inhibitor. It is a PI3Kβ inhibitor with IC50 of 10 nM, 8-, 87- and 109-fold more selective to PI3Kβ than PI3Kδ, PI3Kα and PI3Kγ in cell-free assays. by targeting PI3Kβ, AZD-6482 specifically inhibits thrombosis without interfering with normal haemostasis. Therefore, AZD-6482 is used as an anti-thrombotic drug for the prophylaxis of thrombotic disorders. AZD-6482 was in phase I trials by AstraZeneca for the prevention of thrombosis. However, the study was discontinued.

Foropafant is a platelet-activating factor (PAF) antagonist which was developed by Sanofi. It was in clinical development for the treatment of asthma, thrombosis and ulcerative colitis. The development of the drug was discontinued due to lack of efficacy.

Tiplasinin (PAI-039) is an orally efficacious and selective plasminogen activator inhibitor-1 (PAI-1) inhibitor. Tiplasinin bound specifically to the active conformation of PAI-1 and exhibited reversible inactivation of PAI-1 in vitro. Tiplaxtinin exhibited in vivo oral efficacy in two different models of acute arterial thrombosis. The remarkable preclinical safety and metabolic stability profiles of tiplaxtinin led to advancing the compound to Phase-I clinical trial for Thrombosis, which was later discontinued.

Lotrafiban (SmithKline Beecham) is a member of the latest generation of orally-active platelet GPIIb/IIIa blockers undergoing Phase III clinical trials to test the relative effectiveness versus other oral platelet inhibitors for ischaemic conditions including unstable angina, restenosis after PCI and stroke. Lotrafiban is converted from an esterified prodrug by plasma and liver esterases to a peptidomimetic of the arginine-glycine-aspartic acid amino acid sequence. This sequence itself mimics the binding site of fibrinogen and von Willebrand Factor to the platelet GPIIb/IIIa receptor. Preliminary results of the clinical trial APLAUD (antiplatelet useful dose) show that lotrafiban is clinically safe and well-tolerated in patients with recent myocardial infarction, unstable angina, transient ischaemic attack (TIA), or stroke when added to aspirin therapy. The Blockade of the IIb/IIIa Receptor to Avoid Vascular Occlusion (BRAVO) trial of SmithKline Beecham's oral GpIIb/IIIa blocker, lotrafiban, has been stopped early because of concerns about both safety and efficacy. The drug was showing a higher mortality rate than placebo, and was also associated with an increased incidence of serious thrombocytopenia and major bleeding. As a result of these findings the company has discontinued development of lotrafiban.

Elarofiban is a novel nonpeptide glycoprotein IIb/IIIa (GPIIb/IIIa) antagonist. It inhibits thrombin-induced platelet aggregation in human gel-filtered platelets and platelet aggregation in human platelet-rich plasma (PRP) in response to collagen, arachidonic acid, ADP, and SFLLRN-NH(2). Elarofiban had adequate oral pharmacokinetics in dogs and excellent oral pharmacodynamics. Elarofiban has been in phase II clinical trials for the treatment of myocardial infarction and thrombosis. However, this research has been discontinued.

Dazmegrel [UK 38485] is a thromboxane synthetase inhibitor which was undergoing development in the treatment of thrombosis, ischaemic heart disease, arrhythmias and asthma. Pfizer were conducting phase II studies in Denmark and the UK, phase I studies in Germany and Italy, and preclinical studies in France. Later this research was discontinued.

Staurosporine is an alkaloid isolated from the culture broth of Streptomyces staurosporesa. It exerts antimicrobial, hypotensive, and cytotoxic activity. The main biological activity of staurosporine is the inhibition of protein kinases through the prevention of ATP binding to the kinase. This is achieved through the stronger affinity of staurosporine to the ATP-binding site on the kinase. Staurosporine is a prototypical ATP-competitive kinase inhibitor in that it binds to many kinases with high affinity, though with little selectivity. It is a potent, cell permeable protein kinase C inhibitor with an IC50 of 0.7 nM. At higher concentration (1-20 nM), staurosporine also inhibits other kinases such as PKA, PKG, CAMKII and Myosin light chain kinase (MLCK). At 50-100 nM, it is a functional neurotrophin agonist, promoting neurite outgrowth in neuroblastoma, pheochromocytoma and brain primary neuronal cultures. At 0.2- 1 uM, staurosporine induces cell apoptosis. Staurosporine is also a potent GSK-3β inhibitor with a reported IC50 value of 15 nM. In research, staurosporine is used to induce apoptosis. It has been found that one way in which staurosporine induces apoptosis is by activating caspase-3. Staurosporine was discovered to have biological activities ranging from anti-fungal to anti-hypertensive. The interest in these activities resulted in a large investigative effort in chemistry and biology and the discovery of the potential for anti-cancer treatment. Staurosporine induces apoptosis by multiple pathways and that the inhibition of more than one kinase is responsible for its potent activity. Because the mechanism of action of staurosporine is distinct from traditional anticancer drugs, this may warrant further preclinical evaluations of the antitumor potential of new staurosporine derivatives either alone or in combination with death ligands or conventional chemotherapeutic drugs.

BW 245C is a DP receptor agonist. Systemic administration of BW 245C to healthy volunteers lead to inhibition of platelet aggregation responses to ADP. BW245C was found to be effective in reducing human intraocular pressure, but its clinical usefulness as anti-glaucoma drugs is limited by the extraocular side effects.