Cangrelor

BACKGROUND: Agents that act as antagonists at P2Y(12) ADP receptors on platelets are in use (clopidogrel), and in development for use (cangrelor and prasugrel), in patients with cardiovascular disease. Cangrelor is a direct-acting reversible antagonist being developed for short-term infusion; clopidogrel and prasugrel are oral prodrugs that provide irreversible inhibition via transient formation of active metabolites. At the cessation of cangrelor infusion, patients are likely to receive clopidogrel or prasugrel as a means of maintaining antiplatelet therapy. OBJECTIVES: To apply an experimental in vitro approach to investigate the possibility that cangrelor influences the ability of the active metabolites of clopidogrel and prasugrel to inhibit ADP-mediated platelet function. METHODS: The effects of cangrelor and the active metabolites of clopidogrel (C-AM) and prasugrel (P-AM) on platelet function were assessed by ADP-induced platelet P-selectin expression in whole blood. The method involved rapid removal of the antagonists by dilution, and measurement of residual platelet inhibition. RESULTS: Cangrelor, C-AM and P-AM markedly inhibited P-selectin expression. The effect of cangrelor, but not of C-AM and P-AM, was reversible following antagonist removal. Preincubation of blood with cangrelor prior to addition of C-AM or P-AM reduced the ability of metabolites to irreversibly antagonize P2Y(12). Irreversible inhibition was maintained when blood was preincubated with metabolites prior to cangrelor. CONCLUSIONS: Cangrelor influences the ability of the active metabolites of clopidogrel or prasugrel to inhibit platelet function irreversibly. Careful consideration should be given to the timing of administration of an oral P2Y(12) antagonist following cangrelor infusion.

Concomitant administration of cangrelor with the thienopyridine antiplatelet drugs clopidogrel or prasugrel decreases the antiplatelet effect of clopidogrel and prasugrel by blocking P2Y12-receptor binding of the active metabolites of these drugs. Oral maintenance antiplatelet therapy with clopidogrel or prasugrel should not be administered until the cangrelor infusion has been discontinued.

In several large clinical trials, serum ALT elevations were no more frequent with cangrelor therapy than with placebo [9% vs 12%] or with comparator arms [6.6% vs 6.8%] and no cases of clinically apparent liver injury with jaundice were reported. In addition, since marketing and release, there have been no published reports of clinically apparent liver injury or jaundice associated with cangrelor therapy and hepatotoxicity is not mentioned in the product label.

IDENTIFICATION AND USE: Cangrelor is a platelet aggregation inhibitor and purinergic P2Y receptor antagonist. HUMAN STUDIES: Cangrelor is a potent intravenous platelet P2Y12 receptor antagonist with rapid onset and offset of action. In patients undergoing percutaneous coronary interventions (PCI), compared with control, cangrelor (30 ug/kg bolus, followed immediately by a 4 ug/kg per minute infusion for 2-4 hr or until the conclusion of the index PCI, whichever was longer) reduces periprocedural thrombotic complications without an increase in major bleeding complications, although minor bleeding is increased. In a large clinical trial program of patients undergoing PCI, cangrelor overdosing was rare and not associated with an increase in bleeding complications, an observation that may be attributed to its very short-half life and rapid offset of action. Platelet P2Y12 receptor expression is significantly increased and the receptor is constitutively activated in patients with type 2 diabetes mellitus, which contributes to platelet hyperactivity and limits antiplatelet drug efficacy in type 2 diabetes mellitus. Cangrelor was non-mutagenic and non-clastogenic in genetic toxicology studies, including chromosome aberration assay in human peripheral lymphocytes. ANIMAL STUDIES: Cangrelor had no significant effect on male or female rats fertility treated for 28 days, or on early embryonic development. In embryo-fetal development studies in rats, cangrelor produced dose-related fetal growth retardation characterized by increased incidences of incomplete ossification and unossified hind limb metatarsals. In rabbits, cangrelor was associated with increased incidences of abortion and intrauterine losses, as well as fetal growth retardation. Cangrelor was non-mutagenic and non-clastogenic in genetic toxicology studies, including in vitro bacterial gene mutation assay, mouse lymphoma thymidine kinase assay, and in vivo bone marrow micronucleus assay in mice.

Severe toxicity related specifically to cangrelor is rare. Nevertheless, some potential toxicity concerns are associated with cangrelor use, including bleeding, allergic reactions, thrombocytopenia, and local site reactions. Data on cangrelor overdose were assessed in a pooled analysis of the CHAMPION trials. The study identified 36 patients who experienced an overdose of cangrelor. In most cases, the cangrelor dose did not exceed 2.5 times the recommended dosage. Notably, only 1 patient who experienced an overdose had a severe bleeding event.

/EPIDEMIOLOGY STUDIES/ Overdosing of parenteral antithrombotic therapies can increase the risk of bleeding. Cangrelor is a potent intravenous platelet P2Y12 receptor antagonist with rapid onset and offset of action. In patients undergoing percutaneous coronary interventions (PCI), compared with control, cangrelor (30 ug/kg bolus, followed immediately by a 4 ug/kg per minute infusion for 2-4 hr or until the conclusion of the index PCI, whichever was longer) reduces periprocedural thrombotic complications without an increase in major bleeding complications, although minor bleeding is increased. The impact of cangrelor overdosing on bleeding is unknown and represented the aim of this analysis. Patients with cangrelor overdosing were identified among safety population patients enrolled in the CHAMPION program (n = 25,107). Overdose was defined as administration of an excess >20 % of the bolus dose (30 ug/kg) and/or infusion rate (4 ug/kg per min). Bleeding complications were assessed. Among the safety analysis population in the CHAMPION program, 12,565 patients received cangrelor. A total of 36 overdosed cangrelor patients (0.29 %) were identified in this pooled analysis (20 with both bolus and infusion, 5 with bolus only, and 11 with infusion only). In the majority of patients, the dose did not exceed 2.5 times the recommended dose. Bleeding events were balanced between treatment arms and were consistent with those in the overall CHAMPION program. Only one overdosed patient experienced a serious bleed. There was no correlation between bleeding and magnitude of cangrelor overdose. In a large clinical trial program of patients undergoing PCI, cangrelor overdosing was rare and not associated with an increase in bleeding complications, an observation that may be attributed to its very short-half life and rapid offset of action.

/EPIDEMIOLOGY STUDIES/ CONTEXT: Oral reversible platelet P2Y12 receptor inhibitors (ticagrelor and elinogrel) cause double-digit rates of dyspnea, while irreversible oral antiplatelet drugs (aspirin, ticlopidoine, clopidogrel, and prasugrel) or intravenous glycoprotein IIb/IIIa inhibitors (abciximab, eptifibatide, or tirofiban) do not increase the incidence of dyspnea in randomized trials. Dyspnea after oral reversible antiplatelet agents remains unexplained. A transfusion-related acute lung injury (TRALI) hypothesis has been proposed. The dyspnea risks after cangrelor, an intravenous reversible antiplatelet agent, are not well defined but may offer a universal mechanism linking TRALI, dyspnea, and reversible platelet inhibition. OBJECTIVE: We analyzed safety data from recent head-to-head randomized trials with reversible antiplatelet agents (ticagrelor, elinogrel, and cangrelor) compared to irreversible (clopidogrel/placebo) comparators. RESULTS: All three reversible antiplatelet agents cause excess dyspnea. In contrast to the high double-digit rates after oral ticagrelor or elinogrel, the dyspnea risks after intravenous cangrelor were smaller (<2%) but still consistently and significantly higher than in the corresponding control arms. CONCLUSIONS: The clinical utility of reversible antiplatelet strategies has been challenged. Despite a potential advantage of fewer bleeding events during heart surgery, reversible antiplatelet agents carry the risk of potential autoimmune reactions manifesting as dyspnea. Repeated binding and unbinding cycles, impaired platelet turnover, and lung sequestration or apoptosis of overloaded destructive platelets are among the potential mechanism(s) responsible for dyspnea after reversible antiplatelet agents.

Drug Induced Liver Injury Rank (DILIrank 2.0)

Cangrelor

vNo-DILI-concern

0

No match

DOI:10.1016/j.drudis.2016.02.015

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Cangrelor had no significant effect on male or female rat fertility treated for 28 days, or on early embryonic development at steady state plasma concentration (Css) of approximately the same as that achieved in the PCI (percutaneous coronary intervention) setting at the MRHD (maximum recommended human dose).

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ In embryo-fetal development studies in rats, cangrelor produced dose-related fetal growth retardation characterized by increased incidences of incomplete ossification and unossified hind limb metatarsals at plasma concentration of approximately 5 times lower than that achieved in the PCI setting at the maximum recommended human dose (MRHD). In rabbits, cangrelor was associated with increased incidences of abortion and intrauterine losses, as well as fetal growth retardation at plasma concentrations of approximately 12 times higher than the PCI setting at the MRHD.

/GENOTOXICITY/ Cangrelor was non-mutagenic and non-clastogenic in genetic toxicology studies, including in vitro bacterial gene mutation assay, mouse lymphoma thymidine kinase assay, ... and in vivo bone marrow micronucleus assay in mice.

Although dosage adjustment is not required because of renal impairment, worsening renal function has been reported in some patients with existing severe renal impairment (creatinine clearance less than 30 mL/minute) who received cangrelor in clinical trials.

Cangrelor should not be used in patients with substantial active bleeding. The antiplatelet effects of cangrelor are negligible 1 hour after discontinuance of the infusion.

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/

/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W TKO /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) or lorazepam (Ativan) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

The Approved Drug Products with Therapeutic Equivalence Evaluations identifies currently marketed prescription drug products, including cangrelor, approved on the basis of safety and effectiveness by FDA under sections 505 of the Federal Food, Drug, and Cosmetic Act.

Platelet Aggregation Inhibitors; Purinergic P2Y Receptor Antagonists

MEDICATION