The Prognostic Value of ADP-Induced Platelet Aggregation for Bleeding Complications in Low - Intermediate Risk Patients with Acute Coronary Syndrome Taking Clopidogrel After Percutaneous Coronary Intervention

Testing P2Y12 platelet inhibitors generics beyond bioequivalence: a parallel single-blinded randomized trial

Cardiovascular diseases are the leading cause of death worldwide. Ticagrelor is an oral antiplatelet drug used in acute coronary syndrome. Although generic drugs are approved for their bioequivalence to the original product, they are not necessarily to be therapeutically equivalent. This study was conducted to prove the efficacy and safety of ticagrelor generically named Ticaloguard® compared to its brand Brilique® in healthy volunteers. A loading dose of 180 mg ticagrelor named Brilique® or Ticaloguard® followed by a 90 mg twice daily regimen as maintenance dose was given to 14 and 15 volunteers in Tica and Brili groups, respectively. The platelet aggregation on the ADP agonist was assessed at baseline and repeated 1 h and 3 h after the loading dose, on day 4 (after reaching steady-state), 12 and 24 h after discontinuation of the antiplatelet drug. Adverse effects from trial medications were noted by direct questions. It was shown that generic Ticaloguard® provides a similar therapeutic effect and safety as its branded Brilique® (p > 0.05). This will permit safe and trusted use of the generic Ticaloguard® when treating it in the same manner as Brilique®. Testing generic drug effects rather than simple bioequivalency, especially for drugs that are used in critical life-threatening situations, is crucial. We advocate applying this form of a clinical trial to test surrogate clinical efficacy for generics used in critical indications before having real-world data whenever possible.

Effects of whole blood storage in a polyolefin blood bag on platelets for acute normovolemic hemodilution

Acute normovolemic hemodilution (ANH) is a potential transfusion method for platelets, as well as for red blood cells. However, previous studies have shown that whole blood storage in ANH decreases platelet aggregability by 14.7–76.3% and that this decrease is not recovered by reinfusion. We investigated whether a new whole blood storage method for 6 h using a polyolefin bag, based on the platelet concentrates storage method, would maintain platelet function better than the conventional method using a polyvinyl chloride bag. We demonstrated that storage of whole blood in a polyolefin bag maintained ADP-induced aggregation rates at more than twofold higher than those in a polyvinyl chloride bag, and also significantly suppressed P-selectin expression, a platelet activation marker (ADP-induced aggregation rates: 24.6 ± 5.1% vs. 51.7 ± 11.5%, p = 0.002; P-selectin expression; 50.3 ± 8.4MFI vs. 31.6 ± 9.3MFI, p = 0.018). These results could be attributed to the high gas permeability of polyolefin, which lowered PCO₂ and maintained a high pH with or without agitation. There were no significant changes in platelet count and red blood cell parameters due to the storage methods. Our results suggest that ANH using polyolefin bags is advantageous in improving hemostatic function compared to the conventional method.

Antibody-Based Ticagrelor Reversal Agent in Healthy Volunteers

BACKGROUND

Ticagrelor is an oral P2Y₁₂ inhibitor that is used with aspirin to reduce the risk of ischemic events among patients with acute coronary syndromes or previous myocardial infarction. Spontaneous major bleeding and bleeding associated with urgent invasive procedures are concerns with ticagrelor, as with other antiplatelet drugs. The antiplatelet effects of ticagrelor cannot be reversed with platelet transfusion. A rapid-acting reversal agent would be useful.

METHODS

In this randomized, double-blind, placebo-controlled, phase 1 trial, we evaluated intravenous PB2452, a monoclonal antibody fragment that binds ticagrelor with high affinity, as a ticagrelor reversal agent. We assessed platelet function in healthy volunteers before and after 48 hours of ticagrelor pretreatment and again after the administration of PB2452 or placebo. Platelet function was assessed with the use of light transmission aggregometry, a point-of-care P2Y₁₂ platelet-reactivity test, and a vasodilator-stimulated phosphoprotein assay.

RESULTS

Of the 64 volunteers who underwent randomization, 48 were assigned to receive PB2452 and 16 to receive placebo. After 48 hours of ticagrelor pretreatment, platelet aggregation was suppressed by approximately 80%. PB2452 administered as an initial intravenous bolus followed by a prolonged infusion (8, 12, or 16 hours) was associated with a significantly greater increase in platelet function than placebo, as measured by multiple assays. Ticagrelor reversal occurred within 5 minutes after the initiation of PB2452 and was sustained for more than 20 hours (P<0.001 after Bonferroni adjustment across all time points for all assays). There was no evidence of a rebound in platelet activity after drug cessation. Adverse events related to the trial drug were limited mainly to issues involving the infusion site.

CONCLUSIONS

In healthy volunteers, the administration of PB2452, a specific reversal agent for ticagrelor, provided immediate and sustained reversal of the antiplatelet effects of ticagrelor, as measured by multiple assays. (Funded by PhaseBio Pharmaceuticals; ClinicalTrials.gov number, NCT03492385.).