Antiplatelet agents for preventing vaso-occlusive events in people with sickle cell disease: a systematic review.

BACKGROUND: Sickle cell disease (SCD) is the most common hemoglobinopathy, occurring worldwide, and vaso-occlusive events (VOEs) are its paramount, hallmark clinical manifestation. Evidence exists that platelets play an important role in generating VOEs. OBJECTIVE: To assess the clinical benefits and harms of antiplatelet agents for preventing VOEs in patients with SCD. METHODS: We conducted searches of the Cochrane Central Register of Controlled Trials (CENTRAL; up to 2018, issue 3 of 12), PubMed/MEDLINE (up to April 20, 2018), and the Excerpta Medica database (EMBASE; from 1980 to week 16 of 2018). We also searched the Latin American and Caribbean Health Sciences Literature (LILACS) database, the US Food and Drug Administration (FDA) website, the European Medicines Agency (EMA) website, the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), and www.ClinicalTrials.gov. We checked the bibliographies of included studies and any relevant systematic reviews. Our systematic review included randomized clinical trials (RCTs) conducted in people who had SCD without VOEs at trial entry. Eligible trials compared a single or combination treatment regimen (with each treatment classified as a conventional or nonconventional antiplatelet agent) with conventional care, placebo, or another regimen. No restrictions were placed on the route of administration, dose, frequency, or duration of treatment. We selected RCTs, assessed the risk for bias, and extracted data in a duplicate and independent fashion. We estimated risk ratios for dichotomous outcomes and mean differences for continuous outcomes. We also subjected our analyses to a random-effects model, and Trial Sequential Analysis (TSA) was used. We used the grading of recommendations, assessment, development, and evaluation (GRADE) approach to assess the overall quality of data for each individual outcome. RESULTS: We identified 5 RCTs (N=747) that met our criteria. Of these, 4 trials were multicenter and multinational. The trials included patients of all ages and assessed prasugrel, ticagrelor, crizanlizumab, and aspirin vs either placebo or no intervention. The most frequent route of administration was oral. The trials were small and carried a high risk for bias, given that pharmaceutical companies sponsored 4 of them. None of the trials reported information on quality of life. No meta-analysis was performed owing to heterogeneity in the ages of the participants and in the interventions. No single trial showed evidence of certainty regarding all-cause mortality. One trial showed uncertainty in comparing prasugrel vs placebo for preventing VOEs in patients younger than 18 years (relative risk [RR], 0.92; 95% CI, 0.80 to 1.06; low quality of evidence). TSA for this outcome suggested that a new trial should be conducted. One trial found a difference in the size effect of uncomplicated VOEs, favoring high-dose crizanlizumab vs placebo (mean difference, -1.50; 95% CI, -2.61 to -0.39; very low quality of evidence). No difference in VOEs was found in studies that compared either ticagrelor in children or prasugrel in adults vs placebo. The overall incidence of harms in any intervention did not differ from that in the control. CONCLUSIONS: The current evidence does not support or reject the use of any antiplatelet agent for preventing VOEs in people with SCD. This conclusion was based on small RCTs that carried a high risk for bias. No conclusive evidence exists regarding relevant clinical outcomes because the evidence is limited and of very low quality.

Assessment of analytical techniques for characterization of crystalline clopidogrel forms in patent applications

The aim of this study was to evaluate two important aspects of patent applications of crystalline forms of drugs: (i) the physicochemical characterization of the crystalline forms; and (ii) the procedure for preparing crystals of the blockbuster drug clopidogrel. To this end, searches were conducted using online patent databases. The results showed that: (i) the majority of patent applications for clopidogrel crystalline forms failed to comply with proposed Brazilian Patent Office guidelines. This was primarily due to insufficient number of analytical techniques evaluating the crystalline phase. In addition, some patent applications lacked assessment of chemical/crystallography purity; (ii) use of more than two analytical techniques is important; and (iii) the crystallization procedure for clopidogrel bisulfate form II were irreproducible based on the procedure given in the patent application.

Este trabalho tem como objetivo avaliar dois aspectos importantes em um pedido de patente de formas cristalinas de fármacos: (i) caracterização físico-química das formas cristalinas e (ii)o procedimento de preparo da forma II do fármaco clopidogrel, um blockbuster de vendas. Realizaram-se buscas em bancos de dados patentários on line. Os resultados mostraram que (i) a maioria dos pedidos de patente de formas cristalinas do clopidogrel não se adequam com proposta do INPI devido ao número insuficiente de técnicas analíticas utilizadas na caracterização da fase cristalina. Ainda, em alguns pedidos de patente não há a presença da avaliação da pureza química/cristalográfica; (ii) a importância de se utilizar mais de duas técnicas de avaliação e (iii) que não foi possível a reprodução da cristalização com o procedimento apresentado no pedido de patente.

Avanços terapêuticos em cardiologia: parte 4. Antiplaquetários em cardiologia / Terapeutic advances in cardiology: Part 4. Antiplatelets in cardiology

Os autores fazem uma revisäo dos antiagregantes plaquetários disponíveis. Chamam a atençäo que a hirudina é inibidora da trombina, o verapamil é antagonista da adrenalina, o ridogrel e o ômega 3 bloqueiam os endoperóxidos bem como a sulfinpirazona, a aspirina, dipiridamol e ticlopidina. Existem antiagregantes com açäo do fator de ativaçäo plaquetária como a ginkgo-biloba e o diltiazem. Fazem uma revisäo das indicaçöes clínicas destas drogas à luz dos conhecimentos atuais