3-Amino-5,6,7,8-tetrahydrothieno[2,3-b]quinoline-2-carbonitrile: A fluorescent molecule that induces differentiation in PC12 cells

Neural differentiation is triggered by the activation of multiple signaling pathways initiated by various neurotrophic factors. An elucidation of these mechanisms is anticipated to facilitate the prevention of diseases and the development of novel therapeutic approaches. Alternative small-molecule inducers for neuroscience studies are required instead of protein-based reagents for more efficient and convenient experiments. We demonstrated that small molecules of thieno[2,3-b]pyridine derivatives that induce neural differentiation, compounds 3a and 9a in particular, exhibited significant neuritogenic activity in rat pheochromocytoma (PC12) cells. Moreover, 3a displayed pronounced fluorescence and a discernible Stokes shift. Furthermore, the outcome of the experiment conducted on the NGF-insensitive clones of rat PC12 cells, and the results of the intercellular uptake analyses suggested that the 3a-mediated activation of neural differentiation occurred independently of the TrkA receptor. Therefore, 3a portrays potential applicability both as a small molecule reagent to replace novel neurotrophic factors and as a potent fluorescent reagent for various techniques, including bioimaging.

New thiophene, thienopyridine and thiazoline-based derivatives: Design, synthesis and biological evaluation as antiproliferative agents and multitargeting kinase inhibitors

Multitargeting kinase inhibitors recently proved to be a profitable approach for conquering cancer proliferation. The current study represents the design and synthesis of new thiophene, thienopyridine, and thiazoline-based derivatives 4-14a,b. All the target compounds were examined in vitro against three cancer cell lines; the liver (HepG-2), breast (MCF-7), and colon (HCT-116) where the thiophene-based compounds 5a-c, demonstrated the most potent activity. Furthermore, the latter derivatives revealed a safety profile against WI-38 normal cell line of selectivity indices ranging from 4.43 to 17.44. In vitro enzyme assay of 5a-c revealed that the carbohydrazide analog 5c has the most promising multitargeting inhibiting activity against Pim-1, VEGFR-2, and EGFR^WT enzymes of IC₅₀ values; 0.037 ± 0.02, 0.95 ± 0.24, and 0.16 ± 0.05 µM, respectively. As it was the most potent analog, 5c was further subjected to cell cycle and apoptosis analysis. The results indicated that it induced preG1 arrest and an apoptotic effect in the early and late stages. Moreover, further apoptosis studies were carried out for 5c to evaluate its proapoptotic potential. Interestingly, 5c enhanced the levels of Bax/Bcl-2 ratio, p53, and active caspase 3 by 18, 6.4, and 24 folds, respectively compared to the untreated cells. The antimicrobial evaluation showed that only compounds 3 and 5a produced broad-spectrum potency, while 5b and 5c exhibited outstanding antifungal effects. Finally, a molecular docking study was carried out to discover the probable interactions of compound 5c with the active sites of Pim-1, VEGFR-2, and EGFR^WT kinases.

Efficacy and Safety of Prasugrel by Stroke Subtype: A Sub-Analysis of the PRASTRO-I Randomized Controlled Trial

Aims: The efficacy of antiplatelet therapy may vary among different disease subtypes. Prasugrel is generally a more potent, consistent, and fast-acting platelet inhibitor than clopidogrel. This sub-analysis of the phase III comparison of PRAsugrel and clopidogrel in Japanese patients with ischemic STROke (PRASTRO-I) trial aimed to assess the differences in efficacy of these treatments for each stroke subtype.

Methods: In the PRASTRO-I trial, a total of 3,753 patients with ischemic stroke were recruited from 224 centers throughout Japan and randomized (1:1) to prasugrel (3.75 mg/day) or clopidogrel (75 mg/day) for 96 weeks. For the sub-analysis, strokes were classified as large-artery atherosclerosis, small-artery occlusion (lacunar), stroke of other etiology, and stroke of undetermined etiology. The cumulative incidence of primary events (ischemic stroke, myocardial infarction, and death from other vascular cause) and hazard ratios (HRs) were calculated for each subgroup.

Results: For patients with large-artery atherosclerosis, the primary event incidence was 3.8% in the prasugrel group and 4.8% in the clopidogrel group (HR 0.79; 95% confidence interval [CI] 0.45–1.41). For patients with small-artery occlusion, the incidence was 3.3% in the prasugrel group and 3.9% in the clopidogrel group (HR 0.82; 95% CI 0.45–1.50). For patients with stroke of undetermined etiology, the incidence was 4.6% in the prasugrel group and 3.0% in the clopidogrel group (HR 1.56; 95% CI 0.90–2.72). The incidence of bleeding was similar across subtypes.

Conclusions: Although statistical significance was not reached, the efficacy of prasugrel was potentially different between stroke subtypes, warranting further studies.

Discovery and optimization of thienopyridine derivatives as novel urea transporter inhibitors

Urea transporters (UTs) play an important role in the urine concentrating mechanism and are recognized as novel targets for developing small molecule inhibitors with salt-sparing diuretic activity. Thienoquinoline derivatives, a class of novel UT-B inhibitors identified by our group, play a significant diuresis in animal model. However, the poor solubility and low bioavailability limited its further development. To overcome these shortcomings, the structure modification of thienoquinoline was carried out in this study, which led to the discovery of novel thienopyridine derivatives as specific urea transporter inhibitors. Further optimization obtained the promising preclinical candidate 8n with not only excellent inhibition effect on urea transporters and diuretic activity on rat model, but also suitable water solubility and Log P value.

Feasibility of gastric endoscopic submucosal dissection with continuous low-dose aspirin for patients receiving dual antiplatelet therapy

BACKGROUND

Endoscopic submucosal dissection (ESD) for gastric neoplasms during continuous low-dose aspirin (LDA) administration is generally acceptable according to recent guidelines. This retrospective study aimed to investigate the effect of continuous LDA on the postoperative bleeding after gastric ESD in patients receiving dual antiplatelet therapy (DAPT).

AIM

To investigate the feasibility of gastric ESD with continuous LDA in patients with DAPT.

METHODS

A total of 597 patients with gastric neoplasms treated with ESD between January 2010 and June 2017 were enrolled. The patients were categorized according to type of antiplatelet therapy (APT).

RESULTS

The postoperative bleeding rate was 6.9% (41/597) in all patients. Patients were divided into the following two groups: no APT (n = 443) and APT (n = 154). APT included single-LDA (n = 95) and DAPT (LDA plus clopidogrel, n = 59) subgroups. In the single-LDA and DAPT subgroups, 56 and 39 patients were received continuous LDA, respectively. The bleeding rate with continuous single-LDA (10.7%) was similar to that with discontinuous single-LDA (10.3%) (P > 0.99). Although the bleeding rate with continuous LDA in patients receiving DAPT (23.1%) was higher than that with discontinuous LDA in patients receiving DAPT (5.0%), no significant difference was observed (P = 0.141).

CONCLUSION

The bleeding rate with continuous LDA in patients receiving DAPT was not statistically different from that with discontinuous LDA in patients receiving DAPT. Therefore, continuous LDA administration may be acceptable for ESD in patients receiving DAPT, although patients should be carefully monitored for possible bleeding.

Cangrelor: Pharmacology, Clinical Data, and Role in Percutaneous Coronary Intervention

In clinical trials that assessed the safety and efficacy of cangrelor during percutaneous coronary intervention (PCI), cangrelor was administered as a 30-μg/kg bolus followed by a 4-μg/kg/min infusion for at least 2 hours or the duration of the PCI, whichever was longer. Cangrelor is currently indicated as an adjunct to PCI to reduce the risk of myocardial infarction, repeat coronary revascularization, and stent thrombosis in patients who have not been treated with a P2Y₁₂ platelet inhibitor and are not being given a glycoprotein IIb/IIIa inhibitor.

Continuous Use of Thienopyridine May Be as Safe as Low-Dose Aspirin in Endoscopic Resection of Gastric Tumors

Background/Aims

Current guidelines recommend withholding antiplatelets for 5–7 days before high-risk endoscopic procedures. We investigated whether this reduces post-endoscopic submucosal dissection (ESD) bleeding.

Methods

Gastric ESD cases with antiplatelets were retorospectively reviewed. Withholding antiplatelets for 5–7 days before ESD was defined as cessation and 0–4 days as continuation. The rate and risk of post-ESD bleeding according to the types and cessation of antiplatelets were assessed.

Results

Among the 215 patients (117 adenoma and 98 early gastric cancer), 161 patients were on single (94 aspirin, 56 thienopyridine, and 11 other agents), 51 on dual, and 3 on triple antiplatelets. Post-ESD bleeding rates were 12.8% in aspirin users, 3.6% in thienopyridine, 27.5% in dual, 33.3% in triple therapy, and 9.7% in the cessation and 15.0% in the continuation group. Multiple antiplatelets (odds ratio [OR], 2.41; 95% confidence interval [CI], 1.01 to 5.76) and specimen size ≥ 5.5 cm (OR, 2.84; 95% CI, 1.04 to 7.73) were the risk of bleeding, while continuation of thienopyridine (OR, 0.23; 95% CI, 0.05 to 1.09) and antiplatelets (OR, 1.83; 95% CI, 0.68 to 4.94) did not increase the risk of bleeding.

Conclusions

Continuing thienopyridine and aspirin did not increase the risk of post-ESD. Multiple antiplatelet therapy and a large specimen size were independent risk factors of post-ESD bleeding.

New Approaches for the Uses of Cyclohexan-1,4-dione for the Synthesis of 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-b]pyridine Derivatives used as Potential Anti-prostate Cancer Agents and Pim-1 Kinase Inhibitors

BACKGROUND

Among the wide range of heterocycles, tetrahydrobenzothienopyridine derivatives acquired a special attention due to their wide range of pharmacological activities especially the therapeutic activities. Many pharmacological drugs containing the thiophene nucleus were known in the market.

METHOD

A series of tetrahydrobenzothienopyridine derivatives were synthesized from the reaction of 2-amino- 3-benzoyl-4,5-dihydrobenzo[b]thiophen-6(7H)-one, synthesized and used for further heterocyclization reactions through reaction with different reagents.

RESULTS

Antiproliferative evaluations and c-Met kinase, Pim-1 kinase inhibitions were performed where some compounds revealed high activities.

CONCLUSION

The inhibition of the newly synthesized compounds towards c-Met kinase, the five c-Metdependent cancer cell lines (A549, HT-29, MKN-45, U87MG, and SMMC-7721) and one c-Met-independent cancer cell line (H460) were investigated using foretinib as a standard drug. The results showed that compounds 6b, 7e, 9b, 9e, 16c and 20d were more active than foretinib. Furthermore, compounds 6b, 13b, 16b and 16c were selected to examine their Pim-1 kinase inhibition activity, where compounds 16b and 16c were of high potencies with IC50 values of 0.28 and 0.32 µM, while compounds 6b and 13b were less effective (IC50 > 10 µM).

Thieno[2,3-b]pyridine derivatives are potent anti-platelet drugs, inhibiting platelet activation, aggregation and showing synergy with aspirin

Drugs which inhibit platelet function are commonly used to prevent blood clot formation in patients with Acute Coronary Syndromes (ACS) or those at risk of stroke. The thieno[3,2-c]pyridine class of therapeutic agents, of which clopidogrel is the most commonly used, target the P2Y₁₂ receptor, and are often used in combination with acetylsalicylic acid (ASA). Six thieno[2,3-b]pyridine were assessed for in vitro anti-platelet activity; all derivatives showed effects on both platelet activation and aggregation, and showed synergy with ASA. Some compounds demonstrated greater activity when compared to clopidogrel. These compounds, therefore, represent potential novel P2Y₁₂ inhibitors for improved treatment for patients.

Changes in P2Y12 reaction units after switching treatments from prasugrel to clopidogrel in Japanese patients with acute coronary syndrome followed by elective coronary stenting

Patients with ischemic heart disease are administered a dual antiplatelet therapy after percutaneous coronary intervention. This consists of aspirin and thienopyridine, which can be switched from prasugrel to clopidogrel. However, the impact of switching is unknown. This study aimed to determine the efficacy and safety of switching from prasugrel to clopidogrel in Japanese patients. One-hundred and thirty-six patients with acute coronary syndrome scheduled to undergo percutaneous coronary intervention and patients with coronary artery disease requiring elective coronary stenting were enrolled. Patients were randomly assigned into the following groups: prasugrel for 6 weeks at loading/maintenance doses of 20/3.75 mg (Continued Group; n = 68) or prasugrel at 20/3.75 mg for 2 weeks followed by clopidogrel at 75 mg for 4 weeks (Switched Group; n = 68). Aspirin (loading dose/maintenance dose 324/81-100 mg/day) was coadministered in both groups. The primary endpoint was the mean P2Y₁₂ reaction unit (PRU) at week 6 and the secondary endpoint was the PRU in groups subdivided based on the presence of CYP2C19 gene polymorphisms. At week 6, the PRU was significantly lower in the Continued Group relative to the Switched Group (140.7 and 183.0, respectively; P < 0.001), which was also evident after correction with the baseline values (144.1 vs. 176.6, respectively; P = 0.005). Extensive and poor metabolizers in the Switched Group, based on CYP2C19 gene polymorphisms, had significantly higher PRU values than those in the Continued Group. Thus, switching treatments from prasugrel to clopidogrel significantly increased the PRU in patients receiving antiplatelet therapy subsequent to percutaneous coronary intervention. Clinical Trial Registration UMIN ID, UMIN000015122.

Lack of Evidence for Dual Antiplatelet Therapy after Endovascular Arterial Procedures: A Meta-analysis. Eur J Vasc Endovasc Surg. 2016;52:253-262. [PMID: 27241270 DOI: 10.1016/j.ejvs.2016.04.023]

INTRODUCTION

Dual antiplatelet therapy (DAPT) has mainly replaced mono antiplatelet therapy (MAPT) and is recommended after arterial endovascular revascularization. The aim of this meta-analysis was to summarize the available evidence for DAPT after endovascular revascularization throughout the arterial system.

METHODS

A systematic search was performed in Medline, Embase, and the Cochrane Register. Two reviewers independently performed data extraction and quality assessment using the Cochrane Collaboration risk of bias assessment tool. Included in the search were randomized controlled trials (RCTs) comparing DAPT with MAPT after endovascular procedures for the treatment of coronary, carotid, or peripheral artery disease, reporting at least one clinical outcome. Articles were excluded if patients received anticoagulation in addition to antiplatelet therapy in the post-procedural phase. The primary outcome was restenosis or stent thrombosis, and secondary outcomes were major adverse cardiac events (MACE), target lesion revascularization, cerebrovascular accident or transient ischemic attack, bleeding, and death. Meta-analyses of binary outcomes were performed using the random effects model and described as risk ratios (RRs) and 95% confidence intervals (95% CIs). Chi-square tests were used to test for heterogeneity.

RESULTS

Nine articles were included in this study, involving lower limb peripheral arteries (1), carotid arteries (2), and coronary arteries (6). The pooled results of coronary trials showed a RR for restenosis with DAPT of 0.60 (95% CI 0.28-1.31) and for myocardial infarction 0.49 (95% CI 0.12-2.03). In the carotid artery trials the RR for restenosis was 0.22 (95% CI 0.04-1.20) and for peripheral arteries 1.02 (95% CI 0.56-1.82). A meta-analysis of bleeding risk of all the included trials showed a RR of 1.06 (95% CI 0.32-3.52) with DAPT.

CONCLUSION

The available evidence comparing DAPT with MAPT after endovascular arterial revascularization is limited and the majority of trials were conducted in the cardiology field. No significant evidence for superiority of DAPT compared with MAPT was found, but there was also no evidence of an increased bleeding risk with DAPT over MAPT.

Causes of late mortality with dual antiplatelet therapy after coronary stents

AIMS

In the dual antiplatelet therapy (DAPT) study, continued thienopyridine beyond 12 months after drug-eluting stent placement was associated with increased mortality compared with placebo. We sought to evaluate factors related to mortality in randomized patients receiving either drug-eluting or bare metal stents in the DAPT study.

METHODS AND RESULTS

Patients were enrolled after coronary stenting, given thienopyridine and aspirin for 12 months, randomly assigned to continued thienopyridine or placebo for an additional 18 months (while taking aspirin), and subsequently treated with aspirin alone for another 3 months. A blinded independent adjudication committee evaluated deaths. Among 11 648 randomized patients, rates of all-cause mortality rates were 1.9 vs. 1.5% (continued thienopyridine vs. placebo, P = 0.07), cardiovascular mortality, 1.0 vs. 1.0% (P = 0.97), and non-cardiovascular mortality, 0.9 vs. 0.5% (P = 0.01) over the randomized period (Months 12-30). Rates of fatal bleeding were 0.2 vs. 0.1% (P = 0.81), and deaths related to any prior bleeding were 0.3 vs. 0.2% (P = 0.36), Months 12-33). Cancer incidence did not differ (2.0 vs. 1.6%, P = 0.12). Cancer-related deaths occurred in 0.6 vs. 0.3% (P = 0.02) and were rarely related to bleeding (0.1 vs. 0, P = 0.25). After excluding those occurring in patients with cancer diagnosed before enrolment, rates were 0.4 vs. 0.3% (P = 0.16).

CONCLUSION

Bleeding accounted for a minority of deaths among patients treated with continued thienopyridine. Cancer-related death in association with thienopyridine therapy was mainly not related to bleeding and may be a chance finding. Caution is warranted when considering extended thienopyridine in patients with advanced cancer.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00977938.

Prevention of occlusive arterial thrombus formation by a single loading dose of prasugrel suppresses neointimal hyperplasia in mice

The present study examined the effects of prasugrel in a mouse model of thrombosis-induced neointimal hyperplasia. Following carotid artery injury by application of ferric chloride solution, thrombus formation was assessed on Day 1 and neointimal thickening was assessed on Day 21. Single administrations of prasugrel at 0.3-3mg/kg (p.o.) resulted in a dose-related and sustained inhibition of ADP-induced platelet aggregation through 24h. Single and multiple (1 and 3 weeks) administration of prasugrel (3mg/kg loading and 1mg/kg/day maintenance doses) resulted in a marked inhibition of neointimal thickening in the injured artery. In the dose-response study, a single administration of prasugrel at 0.3-3mg/kg (p.o.) dose-relatedly inhibited thrombus formation and neointimal thickening on Days 1 and 21, respectively. The degree of neointimal hyperplasia in the injured artery correlated significantly with the thrombus indices, time to occlusion and patency rate. To explore possible mechanisms of inhibition of neointimal hyperplasia by prasugrel, mRNA expression levels of inflammatory and fibrosis markers were determined in injured arteries. Prasugrel treatment resulted in reduced MCP-1, ICAM-1 and TGF-β mRNA levels on Day 2 (24h after the injury) and Day 8 (1 week after the injury) in the target arteries. In conclusion, we found that a single oral loading dose of prasugrel markedly prevented neointimal hyperplasia by inhibiting platelet activation and thrombus formation and was associated with inhibition of the expression of inflammatory and fibrosis markers, including MCP-1, ICAM-1 and TGF-β, in the injured arteries.

Management of Antiplatelet Agents and Anticoagulants in Patients with Gastrointestinal Bleeding

Antithrombotic drugs (anticoagulants, aspirin, and other antiplatelet agents) are used to treat cardiovascular disease and to prevent secondary thromboembolic events. These drugs are independently associated with an increased risk of gastrointestinal bleeding (GIB), and, when prescribed in combination, further increase the risk of adverse bleeding events. Clinical evidence to inform the choice of endoscopic hemostatic procedure, safe temporary drug cessation, and use of reversal agents is reviewed to optimize management following clinically significant GIB.

Prasugrel Hydrochloride

A comprehensive profile of prasugrel HCl is reported herein with 158 references. A full description including nomenclature, formulae, elemental analysis, and appearance is included. Methods of preparation for prasugrel HCl, its intermediates, and derivatives are fully discussed. In addition, the physical properties, analytical methods, stability, uses and applications, and pharmacology of prasugrel HCl are also discussed.

Real-world observations with prasugrel compared to clopidogrel in acute coronary syndrome patients treated with percutaneous coronary intervention in the United States

OBJECTIVES

To compare 30 and 90 day real-world acute myocardial infarction (AMI) and bleeding related rehospitalization rates in acute coronary syndrome (ACS) patients receiving percutaneous coronary intervention (PCI; ACS-PCI) treated with clopidogrel or prasugrel.

RESEARCH DESIGN AND METHODS

Using the Premier hospital database, ACS-PCI patients receiving a drug-eluting (DES) or bare-metal (BMS) stent and clopidogrel or prasugrel from July 2009 to June 2011 were analyzed. Patients were included based on the prasugrel US prescribing information (USPI), excluding patients with a history of transient ischemic attack/stroke and patients ≥75 years without diabetes or prior MI. The primary endpoint was 30 day adjusted AMI rehospitalization rate. Secondary endpoints included 90 day AMI and 30 and 90 day bleeding-related rehospitalization rates. Treatment comparisons were adjusted using propensity score stratification.

RESULTS

At the index event, prasugrel patients (N = 9404) differed from clopidogrel patients (N = 74,163) by having a lower risk of comorbid conditions associated with bleeding, being more likely younger and male, having ST-elevation MI and receiving a DES. For clopidogrel and prasugrel, respectively, the observed AMI-related rehospitalization rates were 4.7% and 3.9% at 30 days (p < 0.0001) and 6.3% and 5.1% at 90 days (p < 0.0001). After adjustment, prasugrel was associated with ∼10% lower odds of AMI-related rehospitalization (30 days: OR = 0.892 [95% CI: 0.798, 0.998]; 90 days, OR = 0.901 [95% CI: 0.817, 0.994]). Adjusted bleeding-related rehospitalization rates were similar to each other (OR = 1.035 at 30 days [95% CI: 0.765, 1.399]; OR = 0.922 at 90 days [95% CI: 0.725, 1.172]).

STUDY LIMITATIONS

Treatment adherence was not assessed. Bleeding events not resulting in a hospitalization (e.g. office, outpatient, or emergency room visits), deaths outside the hospital, or readmissions to a hospital outside of the Premier alliance were not captured in the database.

CONCLUSIONS

The different patient characteristics between prasugrel- and clopidogrel-treated patients suggest physicians are more selective in choosing patients for prasugrel than recommended in the prasugrel USPI. However, after adjustment for these differences, 30 and 90 day AMI rehospitalization rates were lower for prasugrel-treated patients compared to clopidogrel-treated patients, with no difference in adjusted bleeding-related rehospitalization rates.

Prasugrel-induced hypersensitivity skin reaction

We report a case of hypersensitivity skin reaction to prasugrel. The patient exhibited a generalized skin rash after treatment with prasugrel, which was resolved after discontinuation of prasugrel and substitution to clopidogrel. Clopidogrel was successfully administered as an alternative to prasugrel without any signs of further hypersensitivity.

Transient receptor potential ankyrin 1 (TRPA1) channel activation by the thienopyridine-type drugs ticlopidine, clopidogrel, and prasugrel

Transient receptor potential A1 (TRPA1) is widely expressed throughout the human and animal organism, including the dorsal root ganglia as well as the bladder, stomach and small intestine. Here, we examined the effect of three platelet aggregation inhibitors on TRPA1: ticlopidine, clopidogrel and prasugrel. Utilising fluorometric Ca(2+) influx analysis and electrophysiological whole cell measurements in TRPA1-expressing HEK293 and in human enterochromaffin-like QGP-1 cells, we found that ticlopidine, clopidogrel and prasugrel are direct activators of TRPA1. Although this polymodal channel commonly contributes to the perception of pain, temperature and chemical irritants, recent studies provide evidence for its involvement in the release of serotonin (5-HT) from enterochromaffin cells. Therefore, we further investigated the ability of ticlopidine, clopidogrel and prasugrel to stimulate 5-HT release from QGP-1 cells. We could determine 5-HT in supernatants from cultured QGP-1 cells upon treatment with ticlopidine and clopidogrel but not with prasugrel. These findings indicate that a robust TRPA1 activation by ticlopidine and clopidogrel correlates with the stimulatory effect on the secretion of 5-HT. As recipients of ticlopidine and clopidogrel frequently complain about gastrointestinal adverse events such as nausea, vomiting and diarrhoea, an activation of TRPA1 may contribute to adverse effects of such drugs in the digestive system.

Clopidogrel and proton pump inhibitors - where do we stand in 2012?

Clopidogrel in association with aspirine is considered state of the art of medical treatment for acute coronary syndrome by reducing the risk of new ischemic events. Concomitant treatment with proton pump inhibitors in order to prevent gastrointestinal side effects is recommended by clinical guidelines. Clopidogrel needs metabolic activation predominantly by the hepatic cytochrome P450 isoenzyme Cytochrome 2C19 (CYP2C19) and proton pump inhibitors (PPIs) are extensively metabolized by the CYP2C19 isoenzyme as well. Several pharmacodynamic studies investigating a potential clopidogrel-PPI interaction found a significant decrease of the clopidogrel platelet antiaggregation effect for omeprazole, but not for pantoprazole. Initial clinical cohort studies in 2009 reported an increased risk for adverse cardiovascular events, when under clopidogrel and PPI treatment at the same time. These observations led the United States Food and Drug Administration and the European Medecines Agency to discourage the combination of clopidogrel and PPI (especially omeprazole) in the same year. In contrast, more recent retrospective cohort studies including propensity score matching and the only existing randomized trial have not shown any difference concerning adverse cardiovascular events when concomitantly on clopidogrel and PPI or only on clopidogrel. Three meta-analyses report an inverse correlation between clopidogrel-PPI interaction and study quality, with high and moderate quality studies not reporting any association, rising concern about unmeasured confounders biasing the low quality studies. Thus, no definite evidence exists for an effect on mortality. Because PPI induced risk reduction clearly overweighs the possible adverse cardiovascular risk in patients with high risk of gastrointestinal bleeding, combination of clopidogrel with the less CYP2C19 inhibiting pantoprazole should be recommended.

The significance of clopidogrel low-responsiveness on stent thrombosis and cardiac death assessed by the verifynow p(2)y(12) assay in patients with acute coronary syndrome within 6 months after drug-eluting stent implantation

Background and Objectives

Clopidogrel resistance or low-responsiveness may be associated with recurrent atherothrombotic events after drug-eluting stent (DES) implantation. We prospectively evaluated the association between clopidogrel resistance assessed by the Verifynow™ P₂Y₁₂ assay (Accumetrics, San Diego, CA, USA) and stent thrombosis (ST) or cardiac death (CD) in patients with acute coronary syndrome (ACS) within 6 months after DES implantation.

Subjects and Methods

We enrolled 237 consecutive patients (160 males, 65.2±10.3 years) with ACS who received a DES implantation. The composite endpoint was defined to CD or ST by Academic Research Consortium definitions within 6 months post-implantation. Clopidogrel resistance was defined as <20% inhibition of the P₂Y₁₂ receptor.

Results

Baseline demographic characteristics were similar between 142 normal individuals and 95 clopidogrel resistant patients. CD occurred in one case (0.7%) in the normal group and two cases (2.13%) in the resistant group (p=0.344). There was no episode of ST in the normal group and four episodes in the resistant group (4.2%, four definite ST) (p=0.035). Univariate logistic regression revealed an adjusted odds ratio (OR) for composite end point of CD or ST of 9.646 {95% confidence interval (CI) 1.139-81.679}, and multivariate logistic regression for composite end point revealed an OR of 12.074 (95% CI 1.205-120.992).

Conclusion

Clopidogrel low-responsiveness assessed by the Verifynow™ P₂Y₁₂ assay is an independent predictor of ST and composite end point of ST or CD in patients with ACS within 6 months after DES implantation.