A randomized crossover study comparing the antiplatelet effect of plavix versus generic clopidogrel

Triple versus guideline antiplatelet therapy to prevent recurrence after acute ischaemic stroke or transient ischaemic attack: the TARDIS RCT

BACKGROUND

Two antiplatelet agents are better than one for preventing recurrent stroke after acute ischaemic stroke or transient ischaemic attack (TIA). Therefore, intensive treatment with three agents might be better still, providing it does not cause undue bleeding.

OBJECTIVE

To compare the safety and efficacy of intensive therapy with guideline antiplatelet therapy for acute ischaemic stroke and TIA.

DESIGN

International prospective randomised open-label blinded end-point parallel-group superiority clinical trial.

SETTING

Acute hospitals at 106 sites in four countries.

PARTICIPANTS

Patients > 50 years of age with acute non-cardioembolic ischaemic stroke or TIA within 48 hours of ictus (stroke).

INTERVENTIONS

Participants were allocated at random by computer to 1 month of intensive (combined aspirin, clopidogrel and dipyridamole) or guideline (combined aspirin and dipyridamole, or clopidogrel alone) antiplatelet agents, and followed for 90 days.

MAIN OUTCOME MEASURES

The primary outcome was the incidence and severity of any recurrent stroke (ischaemic, haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days by blinded telephone follow-up. Analysis using ordinal logistic regression was by intention to treat. Other outcomes included bleeding and its severity, death, myocardial infarction (MI), disability, mood, cognition and quality of life.

RESULTS

The trial was stopped early on the recommendation of the Data Monitoring Committee after recruitment of 3096 participants (intensive, n = 1556; guideline, n = 1540) from 106 hospitals in four countries between April 2009 and March 2016. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy in 3070 (99.2%) participants with data [93 vs. 105 stroke/TIA events; adjusted common odds ratio 0.90, 95% confidence interval (CI) 0.67 to 1.20; p = 0.47]. Major (encompassing fatal) bleeding was increased with intensive as compared with guideline therapy [39 vs. 17 participants; adjusted hazard ratio (aHR) 2.23, 95% CI 1.25 to 3.96; p = 0.006]. There were no differences between the treatment groups in all-cause mortality, or the composite of death, stroke, MI and major bleeding (aHR 1.02, 95% CI 0.77 to 1.35; p = 0.88).

LIMITATIONS

Patients and investigators were not blinded to treatment. The comparator group comprised two guideline strategies because of changes in national guidelines during the trial. The trial was stopped early, thereby reducing its statistical power.

CONCLUSIONS

The use of three antiplatelet agents is associated with increased bleeding without any significant reduction in recurrence of stroke or TIA.

FUTURE WORK

The safety and efficacy of dual antiplatelet therapy (combined aspirin and clopidogrel) versus aspirin remains to be defined. Further research is required on identifying individual patient response to antiplatelets, and the relationship between response and the subsequent risks of vascular recurrent events and bleeding complications.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN47823388.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 48. See the NIHR Journal Library website for further project information. The Triple Antiplatelets for Reducing Dependency after Ischaemic Stroke (TARDIS) vanguard phase was funded by the British Heart Foundation (grant PG/08/083/25779, from 1 April 2009 to 30 September 2012) and indirect funding was provided by the Stroke Association through its funding of the Stroke Trials Unit, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK. There was no commercial support for the trial and antiplatelet drugs were sourced locally at each site. The trial was sponsored by the University of Nottingham.

Salts of Clopidogrel: Investigation to Ensure Clinical Equivalence: A 12-Month Randomized Clinical Trial

BACKGROUND

In the present clinical trial, we compared the efficacy and safety of the generic clopidogrel besylate (CB) with the innovator clopidogrel hydrogen sulfate (CHS) salt in patients eligible to receive clopidogrel.

METHODS

A prospective 2-arm, multicenter, open-label, phase 4 clinical trial. Consecutive patients (n = 1864) were screened and 1800 were enrolled in the trial and randomized to CHS or CB. Primary efficacy end point was the composite of myocardial infarction, stroke, or death from vascular causes, and primary safety end point was rate of bleeding events as defined by Bleeding Academic Research Consortium criteria.

RESULTS

At 12-month follow-up, no differences were observed between CB (n = 759) and CHS (n = 798) in primary efficacy and safety end points (age, sex, history of percutaneous coronary intervention adjusted odds ratio [OR], 0.70; 95% confidence interval [CI], 0.41-1.21 and OR, 0.81; 95% CI, 0.51-1.29, respectively) between CHS and CB. Analyses of efficacy and safety in subgroups that were defined according to the qualifying diagnosis revealed that there was no difference between CHS and CB.

CONCLUSION

The efficacy and safety of CB administered for 12 months for the secondary prevention of atherothrombotic events are similar to that of CHS. (Salts of Clopidogrel: Investigation to ENsure Clinical Equivalence, SCIENCE trial; ClinicalTrials.gov Identifier:NCT02126982).

Efficacy and Safety of Glaucoma Patients' Switch from a 2% Dorzolamide/0.5% Timolol Fixed-Combination Brand-Name Drug to Its Generic Counterpart

PURPOSE

To compare the efficacy and safety of the brand-name and generic 2% dorzolamide/0.5% timolol fixed-combination (DTFC) drugs in glaucoma patients.

METHODS

This was a prospective single-center study, in which patients using only the brand-name DTFC (Cosopt(®); Merck and Co, Inc.) drug and those using Cosopt with prostaglandin analogs (PGs) were enrolled. In the patients using Cosopt (Group A) and Cosopt with PGs (Group B), Cosopt was switched to its generic counterpart (Batidor(®); Bausch & Lomb, Inc.). The intraocular pressure (IOP) was measured before the switch and 4, 8, and 12 weeks after the switch in both groups. The questionnaire on the discomfort symptoms and on the discomfort score for the use of eye drops was answered by the patients in both groups before the switch and 12 weeks after the switch.

RESULTS

A total of 112 patients were enrolled in the study, 62 in Group A and 50 in Group B. The IOPs before the switch and 4, 8, and 12 weeks after the switch showed no statistical difference in both groups (P>0.05). There were higher incidences of bitter taste and blurring with Cosopt, and there was a higher incidence of headache with Batidor in both groups, but no significant differences (P>0.05) were noted. There was, likewise, no significant difference in the discomfort score between 2 drugs in both groups (P>0.05).

CONCLUSIONS

After the switch, the IOP-lowering effect of the generic drug Batidor was similar to that of the brand-name drug Cosopt in the monotherapy and combination therapy with PGs. No significant differences were found in terms of the discomfort symptoms and discomfort score between the 2 drugs.

Comparative fasting bioavailability of two clopidogrel formulations in healthy Mediterranean volunteers: an in vitro-in vivo correlation

Objective

The aim of this study was to evaluate the bioequivalence of two drug products, generic clopidogrel bisulfate 75 mg film-coated tablets versus the reference Plavix^® clopidogrel bisulfate 75 mg film-coated tablets.

Methods

Bioequivalence of tablets was tested by comparisons against the reference brand product in accordance with the requirements of the Declaration of Helsinki, the current Good Clinical Practice Guidelines, and the International Conference on Harmonization.

Results

The relationship between concentration and peak area ratio was found to be linear within the range 24.500–1,836.600 pg/mL for clopidogrel. The correlation coefficient (r) was always greater than 0.99 during the course of the validation. Statistical comparison of the main pharmacokinetic parameters showed no significant difference between test and reference. The point estimates (ratios of geometric mean) were 104.122%, 104.184%, and 109.091% for areas under the plasma concentration–time curve (AUC) AUC_0-last, AUC_0-∞, and peak plasma concentration C_max, respectively. These pharmacokinetic parameter values of clopidogrel and its main metabolite lie within the bioequivalence limit (80%–125%) specified by the US Food and Drug Administration and the European Medicines Agency.

Conclusion

The tested drug product was bioequivalent to the reference drug under fasting conditions and had the same safety profile, which is important to achieve equivalent therapeutic effect with the reference.

Switching from generic to brand clopidogrel in male patients after ST-elevated myocardial infarction

OBJECTIVE

To detect residual platelet aggregation following the switch from generic (GC) to brand clopidogrel (BC) in male patients after ST-elevated myocardial infarction (STEMI).

METHODS

The study was designed as an open-label, prospective cohort trial. Thirty-three male STEMI patients were enrolled. All patients received dual antiplatelet therapy with aspirin (100 mg/daily) and one of six GC at a daily dose of 75 mg. After 2 weeks, all patients were switched to BC. Adrenaline- and adenosine diphosphate (ADP)-induced platelet aggregation was assessed twice: on day 14 (before the switch) and on day 21 (after 1 week of BC therapy).

RESULTS

Adrenaline-induced platelet aggregation did not differ among clopidogrel formulations. In contrast, residual 5 µM ADP-induced platelet aggregation after BC differs from GC by 14% (28.0 ± 2.5 vs. 23.9 ± 2.1%; p = 0.03). When 20 µM ADP was used as agonist, the difference was smaller (36.2 ± 2.9 vs. 34.6 ± 2.8%) but still significant (p = 0.04) favoring BC.

CONCLUSIONS

After 2 weeks of therapy, switching from GC to BC was associated with a mild but significant reduction in ADP-induced platelet aggregation in male post-STEMI patients. The observed differences between GC and BC should be confirmed in a larger randomized study, but may represent a risk in underdeveloped countries, where GC therapy is mandatory for post-MI inpatients.

Update: Acute coronary syndromes (V). Personalized antiplatelet therapy

It is well established that high on-treatment platelet reactivity to adenosine diphosphate during clopidogrel therapy is an independent risk factor for ischemic event occurrences in a postpercutaneous coronary intervention patients. However, the precise role of platelet function testing remains debated. Platelet function testing to ensure optimal platelet inhibition has been recommended by some authorities to improve outcomes in patients treated with clopidogrel. Recent prospective, randomized trials of personalized antiplatelet therapy have failed to demonstrate a benefit of platelet function testing in improving outcomes. In this review article, we discuss the mechanisms responsible for clopidogrel nonreponsiveness, recent trials of platelet function testing, and other new developments in the field of personalized antiplatelet therapy.

Comparison of the antiplatelet effect of two clopidogrel bisulfate formulations: Plavix and generic-Egitromb

Due to expansion of the pharmaceutical market it seems necessary to prove the efficacy of the generic drugs. The aim of this study is to compare the effects of two clopidogrel formulations: brand-name-Plavix and generic drug - Egitromb. This is a prospective, randomized study comparing two groups of patients treated with two clopidogrel: brand-name Plavix and generic drug- Egitromb. The 53 consecutive patients with stable coronary artery disease qualifying for coronary angiography and PCI were enrolled in this trial. They were randomized into two groups. In the group A (n = 28) patients received Egitromb 300 mg at admission followed by 8 days of 75 mg Egitromb daily. In the group B (n = 25) patients received Plavix 300 mg on the admission followed by 8 days of 75 mg Plavix maintenance therapy. Blood samples for multiple electrode aggregometry testing were drawn at baseline, 5 hours and 8 days after taking the loading dose. Median values of platelet aggregation inhibition did not differ between the Plavix and Egitromb groups when assessed at baseline: 239AU/min (IQR:329) vs. 209 (IQR:406; p = 0.894), 5 hours after loading: 183 AU/min (IQR:107) vs. 165 (IQR:171; p = 0.831) or at day 8: 174 AU/min (IQR:133) vs. 211 (IQR:133; p = 0.332. The study showed no difference in the therapeutic effect of two clopidogrel formulations (Egitromb and Plavix).