Clopidogrel plus indobufen in acute coronary syndrome patients with hypersensitivity to aspirin undergoing percutaneous coronary intervention

Dual Antiplatelet Alternatives are Associated With Increased Stroke and Death After Transcarotid Revascularization

OBJECTIVE

To define the risks associated with the replacement of dual antiplatelets for alternate medication regimens.

BACKGROUND

Patients undergoing transcarotid artery revascularization (TCAR) for atherosclerotic disease in the Vascular Quality Initiative database from September 2016 to June 2022 were included. In all, 29,802 TCAR procedures were captured between 2016 and 2022, consisting of 24,651 (82.7%) maintained on dual antiplatelet therapy (DAPT) and 5151 (17.3%) on alternative regimens.

METHODS

Patients maintained on DAPT were compared with those on alternative regimens consisting of any combination of single antiplatelet monotherapy and/or anticoagulation.

RESULTS

On univariable analysis, patients on alternative medications were more likely to experience in-hospital death, ipsilateral stroke, any stroke, and transient ischemic attacks compared with patients in the DAPT group. The mortality rate was higher at 1 year in the alternative cohort (4.7% vs 7.0%, P <0.01). The use of alternate medication regimens was associated with increased odds of stroke and the composite outcome of in-hospital stroke/death compared with DAPT. There was also a significant association between alternative medication use and increased odds of in-hospital transient ischemic attack, immediate stent occlusion, and return to the operating room. At 1 year, there was no significant difference in the incidence of stroke between the 2 groups. However, the use of alternate regimens was associated with higher 1-year of mortality after multivariable adjustment.

CONCLUSIONS

Patients not maintained on DAPT after TCAR experienced an increased risk of stroke and death in the perioperative and follow-up periods. Increased surgeon vigilance is required to ensure compliance with dual antiplatelets as recommended.

Indobufen versus aspirin in patients with acute ischaemic stroke in China (INSURE): a randomised, double-blind, double-dummy, active control, non-inferiority trial

BACKGROUND

Aspirin is recommended for secondary stroke prevention in patients with moderate-to-severe ischaemic stroke but can lead to gastrointestinal intolerance and bleeding. Indobufen is used as an alternative antiplatelet agent in some countries, despite an absence of large-scale clinical trials for this indication. We tested the hypothesis that indobufen is non-inferior to aspirin in reducing the risk of new stroke at 90 days in patients with moderate-to-severe ischaemic stroke.

METHODS

We conducted a randomised, double-blind, double-dummy, active control, non-inferiority trial at 163 tertiary and district general hospitals in China. Eligible participants were aged 18-80 years with acute moderate-to-severe ischaemic stroke (National Institutes of Health Stroke Scale score 4-18). We randomly assigned (1:1) participants within 72 h of the onset of symptoms to receive either indobufen (100 mg tablet twice per day) or aspirin (100 mg tablet once per day) for 90 days. The randomisation sequence was computer generated centrally and stratified by local participating centres. Masked local investigators assigned the random code to patients in ascending order and provided a treatment kit corresponding to the random code. The primary efficacy outcome was new stroke and the primary safety outcome was severe or moderate bleeding, both within 90 days. This primary efficacy outcome was assessed in all randomly assigned and consenting patients and in a per-protocol group (ie, all patients finishing the treatment without major violation of the trial protocol). Safety analyses were done in the safety-analysis population (ie, all patients who received at least one dose of the study drug and had a safety assessment available). We assessed the non-inferiority of indobufen versus aspirin using the one-sided upper limit of the 95% CI of the hazard ratio (HR) with a prespecified non-inferiority margin of 1·25. This trial is registered with ClinicalTrials.gov (NCT03871517).

FINDINGS

This trial took place between June 2, 2019, and Nov 28, 2021. Of 84 093 patients screened, 5438 patients were randomly assigned to receive either indobufen (n=2715) or aspirin (n=2723), all of whom were included in the primary analyses. Median age was 64·2 years (IQR 56·1-70·6); 1921 (35·3%) were women and 3517 (64·7%) were men. Stroke occurred within 90 days in 213 (7·9%) patients in the indobufen group versus 175 (6·4%) in the aspirin group (HR 1·23, 95% CI 1·01-1·50; pnon-inferiority=0·44). Moderate or severe bleeding occurred in 18 (0·7%) patients in the indobufen group and in 28 (1·0%) in the aspirin group (0·63, 95% CI 0·35 to 1·15; p=0·13). Adverse events within 90 days occurred in 666 (24·5%) patients in the indobufen group and 679 (24·9%) patients in the aspirin group (p=0·73).

INTERPRETATION

In patients with acute moderate-to-severe ischaemic stroke, indobufen was not non-inferior to aspirin because the upper limit of the 95% CI was greater than 1·25. Furthermore, indobufen seemed to be inferior to aspirin in reducing the risk of recurrent stroke at 90 days because the lower limit of the 95% CI was greater than 1·00. Although moderate or severe bleeding did not differ between groups, these findings do not support the use of indobufen for secondary stroke prevention in patients with moderate-to-severe ischaemic stroke.

FUNDING

Hangzhou Zhongmei Huadong Pharmaceutical and Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Indobufen or Aspirin on Top of Clopidogrel After Coronary Drug-Eluting Stent Implantation (OPTION): A Randomized, Open-Label, End Point-Blinded, Noninferiority Trial

BACKGROUND

Dual antiplatelet therapy (DAPT) with aspirin as a background therapy has become the standard care after percutaneous coronary intervention. However, some adverse noncardiac effects limited the use of aspirin in clinical practice. Thus, evaluation of pharmacological alternatives to aspirin is attractive. Previous data indicated that indobufen could lessen the unwanted side effects of aspirin while retaining the antithrombotic efficacy, but its combination with a P2Y₁₂ inhibitor still lacks randomized clinical trial evidence.

METHODS

In this randomized, open-label, noninferiority trial, patients with negative cardiac troponin undergoing coronary drug-eluting stent implantation were randomly assigned in a 1:1 ratio to receive either indobufen-based DAPT (indobufen 100 mg twice a day plus clopidogrel 75 mg/d for 12 months) or conventional DAPT (aspirin 100 mg/d plus clopidogrel 75 mg/d for 12 months). The primary end point was a 1-year composite of cardiovascular death, nonfatal myocardial infarction, ischemic stroke, definite or probable stent thrombosis, or Bleeding Academic Research Consortium criteria type 2, 3, or 5 bleeding. The end points were adjudicated by an independent Clinical Event Committee.

RESULTS

Between January 11, 2018, and October 12, 2020, 4551 patients were randomized in 103 cardiovascular centers: 2258 patients to the indobufen-based DAPT group and 2293 to the conventional DAPT group. The primary end point occurred in 101 patients (4.47%) in the indobufen-based DAPT group and 140 patients (6.11%) in the conventional DAPT group (absolute difference, -1.63%; P_{noninferiority}<0.001; hazard ratio, 0.73 [95% CI, 0.56-0.94]; P=0.015). Cardiovascular death, nonfatal myocardial infarction, ischemic stroke, and stent thrombosis were observed in 0.13%, 0.40%, 0.80%, and 0.22% of patients in the indobufen-based DAPT group and 0.17%, 0.44%, 0.83%, and 0.17% of patients in the conventional DAPT group (all P>0.05). The occurrence of Bleeding Academic Research Consortium criteria type 2, 3, or 5 bleeding events was lower in the indobufen-based DAPT group compared with the conventional DAPT group (2.97% versus 4.71%; hazard ratio, 0.63 [95% CI, 0.46-0.85]; P=0.002), with the main decrease in type 2 bleeding (1.68% versus 3.49%; hazard ratio, 0.48 [95% CI, 0.33-0.70]; P<0.001).

CONCLUSIONS

In Chinese patients with negative cardiac troponin undergoing drug-eluting stent implantation, indobufen plus clopidogrel DAPT compared with aspirin plus clopidogrel DAPT significantly reduced the risk of 1-year net clinical outcomes, which was driven mainly by a reduction in bleeding events without an increase in ischemic events.

REGISTRATION

URL: https://www.chictr.org.cn; Unique identifier: ChiCTR-IIR-17013505.

Effect of indobufen vs. aspirin on platelet accumulation in patients with stable coronary heart disease after percutaneous coronary intervention: An open-label crossover study

Purpose: This study compared the effect of indobufen with that of aspirin on platelet function in patients with stable coronary heart disease after percutaneous coronary intervention (PCI).

Methods: Patients with stable coronary heart disease who had undergone PCI and received dual antiplatelet therapy (aspirin 100 mg + clopidogrel 75 mg once daily) for at least 12 months were allocated to receive indobufen 100 mg twice daily + clopidogrel 75 mg once daily, clopidogrel 75 mg once daily alone, indobufen 100 mg twice daily alone, and aspirin 100 mg once daily alone for 1 month each in an open-label crossover manner. Platelet function was assessed by using the rates of arachidonic acid (AA)-induced platelet aggregation (AA-PAR) and adenosine diphosphate (ADP)-induced platelet aggregation (ADP-PAR) measured by light transmission aggregometry, the platelet reactivity index measured by vasodilator-stimulated phosphoprotein (PRI-VASP), and the plasma and urinary thromboxane B₂ (TXB₂) concentrations recorded at baseline and during each treatment phase.

Results: Of 56 patients enrolled, 52 completed the study. The AA-PAR was lower in the indobufen alone group than in the aspirin alone group [5.21% (3.39, 7.98) vs. 5.27% (4.06, 6.60), p = 0.038], while biologically, a difference of 0.06% may represent no significant difference; there was no significant between-group difference in the plasma [531.16 pg/ml (203.89, 1035.06) vs. 373.93 pg/ml (194.04, 681.71), p = 0.251] or urinary [3951.97 pg/ml (2006.95, 6077.01) vs. 3610.48 pg/ml (1664.60, 6247.61), p = 0.717] TXB₂ concentration. When the aspirin + clopidogrel group and indobufen + clopidogrel group were compared, similar results were found for AA-PAR [3.97% (3.05, 5.12) vs. 3.83% (3.10, 5.59), p = 0.947] and both plasma [849.47 pg/ml (335.96, 1634.54) vs. 455.41 pg/ml (212.47, 1489.60), p = 0.629], and urinary [4122.97 pg/ml (2044.96, 7459.86) vs. 3812.81 pg/ml (1358.95, 6021.07), p = 0.165] TXB₂ concentrations. ADP-PAR was lower in the clopidogrel alone group than in the indobufen alone group (47.04% ± 16.89 vs. 61.7% ± 10.50, p < 0.001), as was PRI-VASP (66.53% ± 18.06 vs. 77.72% ± 19.87, p = 0.002).

Conclusion: These findings suggest that indobufen has antiplatelet effects similar to those of aspirin in patients with stable coronary heart disease after PCI, and may be an alternative for patients with aspirin intolerance after coronary stenting.

Indobufen versus aspirin in acute ischaemic stroke (INSURE): rationale and design of a multicentre randomised trial

BACKGROUND

Indobufen can reversibly inhibit platelet aggregation and showed to be effective in the treatment of ischaemic heart and peripheral vascular diseases. However, it is unclear whether indobufen is an alternative antiplatelet agent for treatment of patients with ischaemic stroke.

AIM

To test whether indobufen is non-inferior to aspirin in reducing the risk of new stroke at 3 months in patients with moderate to severe ischaemic stroke.

DESIGN

The Indobufen vs Aspirin in Acute Ischaemic Stroke (INSURE) is a randomised, double-blind, double-dummy, positive drug control, non-inferior multicentre clinical trial conducted in 200 hospitals in China. Participants will be randomised at a 1:1 ratio to receive either 100 mg indofufen two times daily or 100 mg aspirin once daily within 72 hours of the onset of symptoms from day 1 to 3 months.

STUDY OUTCOMES

The primary efficacy outcome is a new stroke (ischaemic or haemorrhagic) within 3 months and the primary safety outcome is a severe or moderate bleeding event within 3 months.

DISCUSSION

The INSURE trial will evaluate whether indobufen is non-inferior to aspirin in reducing the risk of new stroke at 3 months in patients with moderate to severe ischaemic stroke.

TRIAL REGISTRATION NUMBER

NCT03871517.

Coronary Artery Disease and Aspirin Intolerance: Background and Insights on Current Management

Aspirin is one of the most widely used medications across the global healthcare system and is the foundation in treating ischemic heart disease, as well as secondary prevention for ischemic and valvular heart disease. Challenges arise in treating patients with cardiovascular disease who have concomitant aspirin intolerance. Through an extensive review of the literature, we provide a comprehensive background on the pharmacology of aspirin, the mechanisms behind aspirin intolerance, the importance of aspirin in cardiovascular disease, and the management of aspirin intolerance in both acute coronary syndrome and stable coronary artery disease. Our review includes a multidisciplinary approach from the internist, allergist/immunologist, and cardiologist when evaluating this important patient population.

Pharmacodynamic effects of indobufen compared with aspirin in patients with coronary atherosclerosis

PURPOSE

This study aimed to investigate the pharmacodynamic effects of indobufen and low-dose aspirin in patients with coronary atherosclerosis.

METHODS

In the first phase, 218 patients with coronary atherosclerosis were randomly assigned to receive aspirin 100 mg once daily (standard dose); 100 mg once every 2 days; 100 mg once every 3 days; 50 mg twice daily; 75 mg once daily; 50 mg once daily; or indobufen 100 mg twice daily for 1 month. In the second phase, 20 healthy subjects were treated with indobufen 100 mg twice daily for 1 week followed after a 2-week washout by aspirin 100 mg once daily for 1 week. The primary outcome was arachidonic acid-induced platelet aggregation (PL_AA), and the secondary outcomes included plasma thromboxane B₂ (TXB₂) and urinary 11-dehydro-TXB₂ (11-dh-TXB₂) levels at the end of each treatment.  RESULTS: In the first phase, compared with aspirin 100 mg once daily: all aspirin groups had similar suppression of PL_AA whereas indobufen group had significantly less suppressed PL_AA. Aspirin given every second or third day, and indobufen produced less suppression of plasma TXB₂. All treatment regimens produced similar inhibition of 11-dh-TXB₂. In the second phase, compared with aspirin, indobufen produced less suppression of plasma TXB₂ at 8 h and 12 h after the last dose.

CONCLUSIONS

Aspirin 50 mg twice daily, 75 mg once daily, and aspirin 50 mg once daily produce antiplatelet effects that are similar to aspirin 100 mg once daily. Aspirin given less often than once daily and indobufen 100 mg twice daily do not suppress platelets as effectively as aspirin 100 mg once daily.

Characterization of an Unknown Impurity in Indobufen Tablets by HPLC-Q-TOF MS and NMR

Background:

Indobufen is a drug that hinders the aggregation of platelets by reversibly repressing the cyclooxygenase enzyme, further bringing about diminished thromboxane production. During quality control of indobufen tablets, an unknown impurity was detected.

Objective:

To characterize an unknown impurity in indobufen tablets.

Methods:

A new method compatible with mass spectrometry detection was set up. A C18 column at 35 °C with a mobile phase consisting of aqueous buffer (including ammonium formate) and methanol (35: 65, v/v) was used at a flow rate of 1.0 mL/min at 228 nm. High-performance liquid chromatography quadrupole time-of-flight mass spectrometry mass spectrometry (HPLC-Q-TOF MS) was used to identify the impurity with the electrospray ionization (ESI) source in the positive ionization mode.

Results:

The results of HPLC-Q-TOF MS analysis indicated that the protonated molecule ions [M + H]+ of the unknown impurity was at m/z 312. Preparative LC method was put into practice with a Prep- C18 column with a mobile phase consisting of water and methanol (20: 80, v/v) at a flow rate of 20.0 mL/min at 228 nm. The assignment of the 1D and 2D NMR signals was performed for the unknown impurity. In addition, possible formation of the novel impurity was also studied.

Conclusion:

An unknown impurity in indobufen tablets was characterized. The impurity was assigned as 2-(4-(1-hydroxy-3-oxoisoindolin-2-yl) phenyl) butanoic acid.

Aspirin Hypersensitivity in Patients Undergoing Percutaneous Coronary Intervention. What Should We be Doing?

Aspirin plays a pivotal role in the management of patients with Coronary Artery Disease (CAD) with well-recognised benefits of reducing recurrent myocardial infarction and minimising the risk of stent thrombosis for those undergoing Percutaneous Coronary Intervention (PCI). Dual antiplatelet therapy is mandated for patients undergoing PCI and typically consists of aspirin and a P2Y12 receptor antagonist. Aspirin hypersensitivity poses a significant clinical dilemma, as the safety and efficacy of oral antiplatelet combinations that exclude aspirin have not been validated. Although, genuine hypersensitivity to aspirin is encountered infrequently, it can be challenging when managing patients with concomitant CAD given the paucity of safe and effective alternatives. Aspirin desensitization is a potential and safe option but may not always be practical. This review aims to highlight the challenges of aspirin hypersensitivity in patients undergoing PCI and propose a treatment algorithm to address this issue in clinical practice.

Effects of four novel genetic polymorphisms on clopidogrel efficacy in Chinese acute coronary syndromes patients

Dual antiplatelet therapy is the gold standard for the clinical treatment of coronary artery disease, especially for acute coronary syndromes patients. However, a substantial number of patients do not respond to clopidogrel despite a standardized dosage regimen, and this is directly associated with poor prognosis. Genetic polymorphisms may be one of the most important factors that contribute to this phenomenon. In this study, we aimed to detect new single nucleotide polymorphisms that can influence the efficacy of clopidogrel in 851 acute coronary syndromes (ACS) patients. Four outcomes (cerebrovascular event, Acute Myocardium Infarction, unstable angina and death) were used as endpoints among three cohorts (northern, central and southern China) of acute coronary syndromes patients. Three SNPs (rs2244923, rs2773341 and rs34428341) were significantly associated with at least one outcome in all subjects. One SNP rs16863352, may play a role in predicting unstable angina in acute coronary syndrome patients ≥75years of age.

Efficacy and Safety of Available Protocols for Aspirin Hypersensitivity for Patients Undergoing Percutaneous Coronary Intervention: A Survey and Systematic Review

BACKGROUND

The most suitable approach for patients with aspirin hypersensitivity undergoing percutaneous coronary intervention remains to be assessed.

METHODS AND RESULTS

Pubmed, Google Scholar, and Cochrane were systematically searched for papers describing protocols about aspirin hypersensitivity in the percutaneous coronary intervention setting. Discharge from hospital with aspirin was the primary end point, whereas rates of adverse reactions being a secondary outcome. An online international survey was performed to critically analyze rates of aspirin hypersensitivity and its medical and interventional management. Eleven studies with 283 patients were included. An endovenous desensitization protocol was performed on one of them, with high efficacy rate (98%) and a low adverse reaction rate when compared with oral administration. No significant differences were reported among the oral protocols in terms of efficacy (less versus more fractionated [95.8% {95.4%-96.2%} versus 95.9% {95.2-96.5%}]), whereas higher incidence of rash and angioedema were reported for protocols with <6 doses escalation (2.6% [1.1%-4.1%] versus 2.6% [1.9%-3.2%]). In the survey, we collected answer from 86 physician of the 100 interviewed. Fifty-six percent of them managed aspirin hypersensitivity changing the therapeutic regimen (eg, clopidogrel monotherapy and indobufen). Despite the previous safety data, desensitization protocols were adopted by only 42% of surveyed cardiologist.

CONCLUSIONS

Available protocols for aspirin hypersensitivity are effective and safe, representing a feasible approach for patients needing dual antiplatelet therapy.

Comparison of aspirin and indobufen in healthy volunteers

The aim of this study is to quantify the extent and recovery of platelet inhibition after administration of indobufen and aspirin in healthy volunteers. Indobufen inhibits platelet aggregation by reversibly inhibiting the platelet cyclooxygenase enzyme, thereby suppressing thromboxane synthesis. Twenty healthy volunteers completed the study and received aspirin (200 mg/day for 2 weeks) followed by a 4-week washout period and then indobufen (200 mg twice a day for 2 weeks). The percent (%) inhibition of platelet aggregation (IPA) was assessed using arachidonic acid (0.5 mg/ml) and adenosine diphosphate (5 µM) at 4, 12, 24 and 48 hours after last dose of each drug. IPA assessed using arachidonic acid as the agonist was similar at 4 hours after the last dose of indobufen (81.07 ± 9.36%) and aspirin (96.99 ± 0.29%, p = 0.10), but significantly lower at 12 hours (74.04 ± 9.55% vs. 97.94 ± 0.28%, p = 0.02), 24 hours (33.39 ± 11.13% vs. 97.48 ± 0.32%, p < 0.001) and 48 hours (14.12 ± 9.74% vs. 98.22 ± 0.31%, p < 0.001) after indobufen, compared to the relative values for aspirin. IPA assessed using adenosine diphosphate as the agonist was similar in the two groups at 4, 12 and 24 hours after the last dose, but significantly lower 48 hours after the last dose of indobufen, compared to the relative value for aspirin (1.98 ± 3.57% vs. 12.61 ± 2.71%, p = 0.002). Indobufen (200 mg twice a day) caused equivalent initial inhibition of platelet aggregation to aspirin (200 mg daily), and the anti-aggregation effect diminished faster than after aspirin.