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Cangrelor is an intravenous antagonist of the P2Y 12 receptor characterized by rapid, potent, predictable, and reversible platelet inhibition. However, cangrelor was not superior to clopidogrel in reducing the incidence of ischemic events in the cangrelor versus standard therapy to achieve optimal management of platelet inhibition (CHAMPION) trials. A prospectively designed platelet function substudy was performed in a selected cohort of patients to provide insight into the pharmacodynamic effects of cangrelor, particularly in regard to whether cangrelor therapy may interfere with the inhibitory effects of clopidogrel. This pre-defined substudy was conducted in a subset of patients from the CHAMPION-PCI trial ( n  = 230) comparing cangrelor with 600 mg of clopidogrel administered before percutaneous coronary intervention (PCI) and from the CHAMPION-PLATFORM trial ( n  = 4) comparing cangrelor at the time of PCI and 600 mg clopidogrel given after the PCI. Pharmacodynamic measures included P2Y12 reaction units (PRU) assessed by VerifyNow P2Y12 testing (primary endpoint marker), platelet aggregation by light transmittance aggregometry following 5 and 20 μmol/L adenosine diphosphate stimuli, and markers of platelet activation determined by flow cytometry. The primary endpoint was the percentage of patients who achieved <20 % change in PRU between baseline and >10 h after PCI. The main trial was stopped early limiting enrollment in the platelet substudy. A total of 167 patients had valid pharmacodynamic assessments for the primary endpoint. The percent of individuals achieving <20 % change in PRU between baseline and >10 h after PCI was higher with cangrelor + clopidogrel (32/84, 38.1 %) compared with placebo + clopidogrel (21/83, 25.3 %), but this was not statistically significant (difference:12.79 %, 95 % CI: −1.18 %, 26.77 %; p  = 0.076). All pharmacodynamic markers as well as the prevalence of patients with high on-treatment platelet reactivity were significantly lower in patients treated with cangrelor. A rapid platelet inhibitory effect was achieved during cangrelor infusion and a rapid offset of action after treatment discontinuation. This CHAMPION platelet function substudy represents the largest pharmacodynamic experience with cangrelor, demonstrating its potent P2Y 12 receptor inhibitory effects, and rapid onset/offset of action. Although there was no significant pharmacodynamic interaction when transitioning to clopidogrel therapy, further studies are warranted given that enrollment in this study was limited due to premature interruption of the main trial.

Indiscriminate activation of opioid receptors provides pain relief but also severe central and intestinal side effects. We hypothesized that exploiting pathological (rather than physiological) conformation dynamics of opioid receptor-ligand interactions might yield ligands without adverse actions. By computer simulations at low pH, a hallmark of injured tissue, we designed an agonist that, because of its low acid dissociation constant, selectively activates peripheral μ-opioid receptors at the source of pain generation. Unlike the conventional opioid fentanyl, this agonist showed pH-sensitive binding, heterotrimeric guanine nucleotide–binding protein (G protein) subunit dissociation by fluorescence resonance energy transfer, and adenosine 3′,5′-monophosphate inhibition in vitro. It produced injury-restricted analgesia in rats with different types of inflammatory pain without exhibiting respiratory depression, sedation, constipation, or addiction potential.

Human tumors can use many different mechanisms to induce dysfunction in the host immune system. Accumulations of inducible regulatory T cells (iTreg, Tr1) are commonly seen in the tumor microenvironment. These Treg express CD39 and up-regulate CD73 ectonucleotidases, hydrolyze exogenous adenosine triphosphate (ATP) to AMP and adenosine and produce prostaglandin E 2 (PGE 2 ). Most tumors also express CD39/CD73 and COX-2 and thus contribute to immune suppression. Pharmacologic inhibitors can be used to eliminate adenosine/PGE 2 production by Tr1 as well as the tumor or to block binding of these factors to their receptors on Teff or to selectively block cAMP synthesis in Teff. These pharmacologic blocking strategies used alone or in combination with conventional treatments or immunotherapies could disarm Tr1, at the same time restoring antitumor functions of Teff.

BACKGROUND--Inhaled frusemide exerts a protective effect against bronchoconstriction induced by several indirect stimuli in asthma. This effect could be caused by interference with neural pathways. The effect of inhaled frusemide on bronchoconstriction induced by inhaled bradykinin, which is thought to cause bronchoconstriction via neural mechanisms, was studied and compared with the effects of adenosine 5'-monophosphate (AMP) which probably produces its airway effects by augmenting mast cell mediator release and interfering with neural pathways. METHODS--Patients first underwent AMP and bradykinin challenges. They were then studied in a randomised, placebo controlled, double blind fashion. Ten atopic asthmatic subjects, studied on four days, were pretreated with inhaled frusemide (40 mg) or placebo for 10 minutes, five minutes before challenge with increasing concentrations of nebulised AMP or bradykinin. RESULTS--On the open visit days the provocative concentrations required to reduce forced expiratory volume in one second (FEV1) by 20% from baseline (PC20) for AMP and bradykinin were 16.23 (1.42-67.16) and 2.75 (0.81-6.6) mg/ml. There was a significant correlation between baseline AMP and bradykinin PC20 values. For AMP the geometric mean PC20 values following pretreatment with inhaled frusemide and matched placebo were 80.97 (9.97- > 400.0) and 14.86 (2.6-104.6) mg/ml respectively (95% CI 0.49 to 0.98). For bradykinin the geometric mean PC20 values following pretreatment with inhaled frusemide and matched placebo were 13.22 (2.53- > 16.0) and 2.52 (0.45-5.61) mg/ml respectively (95% CI 0.43 to 1.01). Frusemide afforded 5.45 and 5.24 fold protection against AMP and bradykinin-induced bronchoconstriction respectively. Furthermore, there was a significant correlation between protection afforded to the airways against AMP and bradykinin. CONCLUSIONS--These data suggest that inhaled frusemide affords protection against bradykinin-induced bronchoconstriction which is comparable to that against AMP, supporting a common mechanism of action for frusemide.

The crystal structure of fructose-1,6-bisphosphatase (Fru-1,6-Pase; EC 3.1.3.11) complexed with Zn2+and two allosteric regulators, AMP and fructose 2,6-bisphosphate (Fru-2,6-P2) has been determined at 2.0-overset⚬ A resolution. In the refined model, the crystallographic R factor is 0.189 with rms deviations of 0.014 overset⚬ A and 2.8⚬from ideal geometries for bond lengths and bond angles, respectively. A 15⚬rotation is observed between the upper dimer C1C2 and the lower dimer C3C4 relative to the R-form structure (fructose 6-phosphate complex), consistent with that expected from a T-form structure. The major difference between the structure of the previously determined Fru-2,6-P2complex (R form) and that of the current quaternary T-form complex lies in the active site domain. A zinc binding site distinct from the three binding sites established earlier was identified within each monomer. Helix H4 (residues 123-127) was found to be better defined than in previously studied ligated Fru-1,6-Pase structures. Interactions between monomers in the active site domain were found involving H4 residues from one monomer and residues Tyr-258 and Arg-243 from the adjacent monomer. Cooperativity between AMP and Fru-2,6-P2in signal transmission probably involves the following features: an AMP site, the adjacent B3 strand (residues 113-118), the metal site, the immediate active site, the short helix H4 (residues 123-127), and Tyr-258 and Arg-243 from the adjacent monomer within the upper (or lower) dimer. The closest distance between the immediate active site and that on the adjacent monomer is only 5 Å. Thus, the involvement of H4 in signal transmission adds another important pathway to the scheme of the allosteric mechanism of Fru-1,6-Pase.

Cangrelor (Kengrexal ® , Kengreal™) is an intravenously administered P2Y 12 receptor inhibitor. It is direct-acting and reversible, with a very rapid onset and offset of action. The randomized, double-blind, multinational, phase III CHAMPION PHOENIX trial compared the efficacy of intravenous cangrelor with that of oral clopidogrel in patients requiring percutaneous coronary intervention (PCI) for stable angina pectoris, a non-ST-segment elevation acute coronary syndrome or ST-segment elevation myocardial infarction (MI). The primary composite efficacy endpoint of death from any cause, MI, ischaemia-drive revascularization or stent thrombosis in the 48 h following randomization occurred in significantly fewer cangrelor than clopidogrel recipients. The rate of severe or life-threatening non-coronary artery bypass graft-related, GUSTO-defined bleeding at 48 h did not significantly differ between cangrelor and clopidogrel recipients. In conclusion, intravenous cangrelor is an important new option for use in patients undergoing PCI who have not been treated with oral P2Y 12 inhibitors.

There is a clinical need for an intravenous P2Y12 inhibitor in patients with acute coronary syndromes (ACS) for patients who are unable to take oral medications or might benefit from a rapidly reversible compound. As the time from admission to percutaneous coronary intervention (PCI) shortens, establishing the benefit of novel therapies impacting ischemic events is increasingly challenging. Cangrelor, an intravenous potent rapidly acting P2Y12 inhibitor, bolus 30 μg/Kg plus infusion of 4 μg/Kg/min, was compared to a 600-mg loading dose of clopidogrel either before or early after PCI in patients with ACS undergoing PCI in The CHAMPION (Cangrelor versus standard tHerapy to Achieve optimal Management of Platelet InhibitiON) PLATFORM and PCI studies. As both CHAMPION studies used similar inclusion/exclusion criteria and death, myocardial infarction, or ischemia-driven revascularization (including stent thrombosis) at 48 hours as their primary end points, the studies were pooled. The clinical events committee adjudicated myocardial infarction. The universal definition was used to define myocardial infarction. A total of 13 049 patients were included. Cangrelor had no effect on the primary end point with the original MI definition (P = .646). With the use of the universal definition, the primary end point was decreased with cangrelor (odds ratio 0.82, 95% confidence interval 0.68-0.99, P = .037). Stent thrombosis was reduced from 0.4% to 0.2% (odds ratio 0.44, 95% confidence interval 0.22-0.87, P = .018). Thrombolysis in Myocardial Infarction major bleeding and transfusions were not increased with cangrelor. With the use of the universal definition of myocardial infarction, cangrelor was associated with a significant reduction in early ischemic events when compared with clopidogrel in patients with non–ST-elevation ACS undergoing PCI.

Adenosine is a potent anticonvulsant acting on excitatory synapses through A1 receptors. Cellular release of ATP, and its subsequent extracellular enzymatic degradation to adenosine, could provide a powerful mechanism for astrocytes to control the activity of neural networks during high-intensity activity. Despite adenosine's importance, the cellular source of adenosine remains unclear. We report here that multiple enzymes degrade extracellular ATP in brain tissue, whereas only Nt5e degrades AMP to adenosine. However, endogenous A1 receptor activation during cortical seizures in vivo or heterosynaptic depression in situ is independent of Nt5e activity, and activation of astrocytic ATP release via Ca2+ photolysis does not trigger synaptic depression. In contrast, selective activation of postsynaptic CA1 neurons leads to release of adenosine and synaptic depression. This study shows that adenosine-mediated synaptic depression is not a consequence of astrocytic ATP release, but is instead an autonomic feedback mechanism that suppresses excitatory transmission during prolonged activity.

COVID-19 caused by the SARS-CoV-2 virus has become a global pandemic. 3CL protease is a virally encoded protein that is essential across a broad spectrum of coronaviruses with no close human analogs. PF-00835231, a 3CL protease inhibitor, has exhibited potent in vitro antiviral activity against SARS-CoV-2 as a single agent. Here we report, the design and characterization of a phosphate prodrug PF-07304814 to enable the delivery and projected sustained systemic exposure in human of PF-00835231 to inhibit coronavirus family 3CL protease activity with selectivity over human host protease targets. Furthermore, we show that PF-00835231 has additive/synergistic activity in combination with remdesivir. We present the ADME, safety, in vitro, and in vivo antiviral activity data that supports the clinical evaluation of PF-07304814 as a potential COVID-19 treatment. The 3CL protease of SARS-CoV-2 is inhibited by PF-00835231 in vitro. Here, the authors show that the prodrug PF-07304814 has broad spectrum activity, inhibiting SARS-CoV and SARS-CoV-2 in mice and its ADME and safety profile support clinical development.

Objectives The objective of this study was to evaluate a US hospital’s cost implications and outcomes of cangrelor use in percutaneous coronary intervention (PCI) patients with two or more angiographic high-risk features (HRFs), including avoidance of oral P2Y 12 inhibitor pretreatment in patients requiring cardiac surgery. Intravenous cangrelor provides direct, immediate onset and rapid-offset P2Y 12 inhibition, which may reduce the necessity for oral P2Y 12 pretreatment. Methods A decision analytic model was developed, estimating the annual impact over 3 years of cangrelor availability. Ischemic and bleeding events (48 h) from randomized clinical trial data were extrapolated to 30 days. Event costs were from the CHAMPION PHOENIX Economics substudy. Rates of coronary artery disease (CAD) presentation, PCI, oral P2Y 12 pretreatment, and inpatient hospitalization costs were from published literature and clinical experts. Scenario analyses evaluated the impact of cangrelor availability on potential reduced P2Y 12 pretreatment rates by 50–100%. Drug costs were 2019 wholesale acquisition costs and, where necessary, all costs were adjusted to 2019 dollars. Results In a hospital treating 1000 CAD PCI inpatients annually, increasing cangrelor use from 11 to 32% resulted in a reduction in 48-h ischemic events/year by 5.7%, while bleeding events increased by 2.9%. Total costs of $1,135,472 declined 12.8%, with a 50% reduction in P2Y 12 pretreatment or 30% with no pretreatment. Savings were driven by a decrease in ischemic events, decrease in glycoprotein IIb/IIIa inhibitor use, and less need for and shorter oral P2Y 12 inhibitor washout period for surgery patients. Conclusion Use of cangrelor in patients with two or more angiographic HRFs may improve outcomes and lower hospital budgets, mainly from avoiding surgery delays necessitated by oral P2Y 12 inhibitor pretreatment.