From the Food and Drug Administration

Teriflunomide-Induced Palmoplantar Pustular Psoriasis: Case Report and Review of the Literature

Teriflunomide is a once-daily oral immunomodulatory disease-modifying treatment for multiple sclerosis (MS). Skin reactions are an infrequent side effect of teriflunomide. Here, we present the case of a 52-year-old female patient with ankylosing spondylitis who was consulted for demyelinating lesions and limb weakness. She was diagnosed with multiple sclerosis and started treatment with teriflunomide. Palmoplantar pustular psoriasis developed after three weeks of treatment initiation. It is a rare side effect related to teriflunomide.

Comparative Studies on the Anticoagulant Profile of Branded Enoxaparin and a New Biosimilar Version

Low molecular weight heparins (LMWH) represent depolymerized heparin prepared by various methods that exhibit differential, biochemical and pharmacological profiles. Enoxaparin is prepared by benzylation followed by alkaline depolymerization of porcine heparin. Upon the expiration of its patent, several biosimilar versions of enoxaparin have become available. Heparinox (Sodic enoxaparine; Cristália Produtos Químicos Farmacêuticos LTDA, Sao Paulo, Brazil) is a new biosimilar form of enoxaparin. We assessed the molecular weight and the biochemical profile of Heparinox and compared its properties to the original branded enoxaparin (Lovenox; Sanofi, Paris, France). Clotting profiles compared included activated clotting time, activated partial thromboplastin time (aPTT), and thrombin time (TT). Anti-protease assays included anti-factor Xa and anti-factor IIa activities. Thrombin generation was measured using a calibrated automated thrombogram and thrombokinetic profile included peak thrombin, lag time and area under the curve. USP potency was determined using commercially available assay kits. Molecular weight profiling was determined using high performance liquid chromatography. We determined that Heparinox and Lovenox were comparable in their molecular weight profile. Th anticoagulant profile of the branded and biosimilar version were also similar in the clot based aPTT and TT. Similarly, the anti-Xa and anti-IIa activities were comparable in the products. No differences were noted in the thrombin generation inhibitory profile of the branded and biosimilar versions of enoxaparin. Our studies suggest that Heparinox is bioequivalent to the original branded enoxaparin based upon in vitro tests however will require further in vivo studies in animal models and humans to determine their clinical bioequivalence.

Unfractionated and Low-Molecular-Weight Heparins, Basic Mechanism of Action and Pharmacology

Unfractionated heparin has enjoyed sole anticoagulant status for nearly 50 years. Despite a dramatic growth in the development and the introduction of many newer anticoagulant and antithrombotic drugs and polytherapeutic approaches during the past decade, unfractionated and low-molecular-weight heparins remain the drugs of choice for many indications, including surgical anticoagulation, interventional cardiology, and in several additional considerations. Unfractionated heparin has a major role in the areas of vascular medicine and surgery, and it is the only parenteral anticoagulant drug that can be empirically neutralized by such agents as protamine sulfate. The development of low and ultra low-molecularweight heparins, which are a class of depolymerized heparin derivatives with distinct pharmacologic profiles that are largely determined by their composition, represents a refinement for the use of heparin. These drugs produce their major effects by combining with antithrombin Ill and exerting antithrombin and anti-Xa inhibition. The low-molecular-weight heparins also increase non-antithrombin III-dependent effects, such as tissue factor pathway inhibitor release, modulation of adhesion molecules, and the release of profibrinolytic and antithrombotic mediators from the blood vessels. Each of the low-molecular-weight heparins has different cumulative effects, and each product exhibits a distinct profile. Initially developed for the prophylaxis of postsurgical deep vein thrombosis, these drugs are now also used for the treatment of both venous and arterial thrombotic disorders. To a large extent, the low-molecular-weight heparins have replaced unfractionated heparin in most of the subcutaneous indications. This has resulted in a dramatic evolution in anticoagulant management that allows patients with thrombotic disorders to be treated in an outpatient setting. Thus, the introduction of low-molecular-weight heparins represents a major advance in improving the use of heparin. Generic versions of these drugs are likely to be developed as their patents expire. Currently, there are no clear guidelines for the acceptance of the generic versions of branded products. To avoid safety and efficacy-related problems, a generic drug must meet both the chemical and biologic equivalence criterion. Synthetically and biosynthetically derived agents such, as pentasaccharide, will also be introduced for clinical use; however, these drugs will have a narrower therapeutic spectrum due to their monotherapeutic nature. Heparin and its derivatives will continue to have a crucial role in the management of thrombotic and cardiovascular disorders in years to come.

Generic Forms of Low-Molecular-Weight Heparins: Some Practical Considerations

This commentary briefly reviews the controversies of therapeutic and generic interchangeability, as they apply to the antithrombotic drug class called low-molecular-weight heparin (LMWH). Recommendations are prepared for the generic LMWH approval process by various regulatory bodies.

Venous thromboembolism prophylaxis

Venous thromboembolism (VTE) can occur after major general surgery. Pulmonary embolism is recognized as the most common identifiable cause of death in hospitalized patients in the United States. The risk of deep venous thrombosis (DVT) and pulmonary embolism (PE) is higher in colorectal surgical procedures compared with general surgical procedures. The incidence of venous thromboembolism in this population is estimated to be 0.2 to 0.3%. Prevention of VTE is considered a patient-safety measure in most mandated quality initiatives. The measures for prevention of VTE include mechanical methods (graduated compression stockings and intermittent pneumatic compression devices) and pharmacologic agents. A combination of mechanical and pharmacologic methods produces the best results. Patients undergoing surgery should be stratified according to their risk of VTE based on patient risk factors, disease-related risk factors, and procedure-related risk factors. The type of prophylaxis should be commensurate with the risk of VTE based on the composite risk profile.

Venous thromboembolism prophylaxis

Venous thromboembolism (VTE) can occur after major general surgery. Pulmonary embolism is recognized as the most common identifiable cause of death in hospitalized patients in the United States. The risk of deep venous thrombosis (DVT) and pulmonary embolism (PE) is higher in colorectal surgical procedures compared with general surgical procedures. The incidence of venous thromboembolism in this population is estimated to be 0.2 to 0.3%. Prevention of VTE is considered a patient-safety measure in most mandated quality initiatives. The measures for prevention of VTE include mechanical methods (graduated compression stockings and intermittent pneumatic compression devices) and pharmacologic agents. A combination of mechanical and pharmacologic methods produces the best results. Patients undergoing surgery should be stratified according to their risk of VTE based on patient risk factors, disease-related risk factors, and procedure-related risk factors. The type of prophylaxis should be commensurate with the risk of VTE based on the composite risk profile.

US Food and Drug Administration approval of generic versions of complex biologics: implications for the practicing physician using low molecular weight heparins

Low-molecular-weight heparins (LMWHs) have shown equivalent or superior efficacy and safety to unfractionated heparin as antithrombotic therapy for patients with acute coronary syndromes. Each approved LMWH is a pleotropic biological agent with a unique chemical, biochemical, biophysical and biological profile and displays different pharmacodynamic and pharmacokinetic profiles. As a result, LMWHs are neither equipotent in preclinical assays nor equivalent in terms of their clinical efficacy and safety. Previously, the US Food and Drug Administration (FDA) cautioned against using various LMWHs interchangeably, however recently, the FDA approved generic versions of LMWH that have not been tested in large clinical trials. This paper highlights the bio-chemical and pharmacological differences between the LMWH preparations that may result in different clinical outcomes, and also reviews the implications and challenges physicians face when generic versions of the original/innovator agents are approved for clinical use.

Differentiation of parenteral anticoagulants in the prevention and treatment of venous thromboembolism

BACKGROUND

The prevention of venous thromboembolism has been identified as a leading priority in hospital safety. Recommended parenteral anticoagulant agents with different indications for the prevention and treatment of venous thromboembolism include unfractionated heparin, low-molecular-weight heparins and fondaparinux. Prescribing decisions in venous thromboembolism management may seem complex due to the large range of clinical indications and patient types, and the range of anticoagulants available.

METHODS

MEDLINE and EMBASE databases were searched to identify relevant original articles.

RESULTS

Low-molecular-weight heparins have nearly replaced unfractionated heparin as the gold standard antithrombotic agent. Low-molecular-weight heparins currently available in the US are enoxaparin, dalteparin, and tinzaparin. Each low-molecular-weight heparin is a distinct pharmacological entity with different licensed indications and available clinical evidence. Enoxaparin is the only low-molecular-weight heparin that is licensed for both venous thromboembolism prophylaxis and treatment. Enoxaparin also has the largest body of clinical evidence supporting its use across the spectrum of venous thromboembolism management and has been used as the reference standard comparator anticoagulant in trials of new anticoagulants. As well as novel oral anticoagulant agents, biosimilar and/or generic low-molecular-weight heparins are now commercially available. Despite similar anticoagulant properties, studies report differences between the branded and biosimilar and/or generic agents and further clinical studies are required to support the use of biosimilar low-molecular-weight heparins. The newer parenteral anticoagulant, fondaparinux, is now also licensed for venous thromboembolism prophylaxis in surgical patients and the treatment of acute deep-vein thrombosis; clinical experience with this anticoagulant is expanding.

CONCLUSIONS

Parenteral anticoagulants should be prescribed in accordance with recommended dose regimens for each clinical indication, based on the available clinical evidence for each agent to assure optimal safety and efficacy.

Comparative glycomics using a tetraplex stable-isotope coded tag

This study illustrates the utility of tetraplex stable isotope coded tags in mass spectrometric glycomics using three carbohydrate classes. The teteraplex tags allow for the direct comparison of glycan compositions within four samples using capillary scale hydrophilic interaction chromatography with online mass spectrometry. In addition, the ability to discern glycan structural isomers is shown based on the tandem mass spectra of each composition using nanospray ionization. Results are shown for chondroitin sulfate proteoglycans, low molecular weight heparins, full length heparins, and N-glycans from alpha-1-acid glycoproteins from four mammalian species. The data demonstrate the value of the tetraplex stable isotope tagging approach for producing high-quality glycomics compositional profiling and fine structural analysis.

Guideline adherence for antithrombotic therapy in acute coronary syndrome: an overview in Dutch hospitals

OBJECTIVE

To assess current Dutch antithrombotic treatment strategies for acute coronary syndrome (ACS) in light of the current European Society of Cardiology (ESC) guidelines.

METHODS

For every Dutch hospital with a coronary care unit (CCU) (n = 93) a single cardiologist was interviewed concerning heparin, thienopyridine and GP IIb/IIIa inhibitor (GPI) treatment. In each hospital, we randomly approached one cardiologist assuming equal policy among physicians employed at the same hospital.

RESULTS

The response rate was 90%. In 59% of hospitals, treatment of ST-elevation myocardial infarction (STEMI) occurred according to the 2008 ESC STEMI guideline, with unfractionated heparin. In contrast, although not recommended, low-molecular-weight heparin (LMWH) was used in 39% (enoxaparin 19%, dalteparin 12%, nadroparin 8%). In non-STEMI, low-molecular-weight-heparins (LMWHs) were used in 97% of all hospitals. Fondaparinux, agent of choice in a noninvasive strategy for the treatment of non-STEMI, was applied in only 2% of hospitals. Although recommended by the ESC, dose adjustment of LMWH therapy for patients with renal failure is not applied in 71% of hospitals. Likewise, LMWH dose adjustment is not applied for patients aged over 75 years in 92% of hospitals.

CONCLUSION

To a great extent treatment of ACS in the Netherlands occurs according to ESC guidelines. Additional benefit may be achieved by routine dose adjustment of LMWH for patients with renal insufficiency and aged >75 years, since these patients are at high risk of bleeding complications secondary to antithrombotic treatment. Periodical evaluation of real-life practice may improve guideline adherence and potentially improve clinical outcome. (Neth Heart J 2010;18:291-9.).

Prevention and treatment of venous thromboembolism with low-molecular-weight heparins: Clinical implications of the recent European guidelines

Venous thromboembolism (VTE) is an important cause of avoidable morbidity and mortality. However, routine prophylaxis for at-risk patients is underused. Recent guidelines issued by an international consensus group, including the International Union of Angiology (IUA), recommend use of low-molecular-weight heparins (LMWHs) for the treatment of acute VTE and prevention of recurrence, and for prophylaxis in surgical and medical patients. This review highlights current inadequacies in the provision of thromboprophylaxis, and considers the clinical implications of the European guidelines on the prevention and treatment of VTE.

Treatment of Cancer-Associated Thrombosis: Distinguishing Among Antithrombotic Agents

The risk of cancer-associated thrombosis can be substantial, depending on tumor type, extent of cancer, and type of treatment. Unfractionated heparin and warfarin have been used in the prevention of cancer-associated thrombosis, but low-molecular-weight heparin (LMWH) is widely used for the prevention of venous thromboembolism in high-risk patients. Long-term management with warfarin is associated with close monitoring, an increased risk of drug interactions, and bleeding. LMWHs may offer an alternative outpatient treatment strategy for prophylactic treatment because of their simpler dosing, more predictable anticoagulant activity, and improved safety profile. Clinical trials examining the treatment of venous thromboembolism with LMWH in patients with cancer suggest a survival advantage for the treated groups. Subtle differences in the pharmacokinetics of available LMWHs exist, and each LMWH should be regarded as a distinct drug. Pharmacists should be aware of the US Food and Drug Administration-approved uses for each LMWH, dosing options, and the advantages and disadvantages of available delivery systems for various patient populations. Pharmacists can play a major role in educating patients and other health care professionals on risk factor recognition, patient risk stratification, and proper agent selection for prevention and treatment of cancer-associated thrombosis.

Unfractionated Heparin, Low Molecular Weight Heparins, and Pentasaccharide: Basic Mechanism of Actions, Pharmacology, and Clinical Use

During the past decade, a large number of new anticoagulant and antithrombotic drugs have been developed. These agents represent a wide variety of substances that are derived using natural sources, biotechnology-based methods, and synthetic approaches. Because of the structural and molecular characteristics, these agents exhibit physicochemical and functional diversities. Thus, each of these classes of drugs controls thrombogenesis by way of distinct mechanisms. The main classes of these new drugs include peptides, peptidomimetics, heparinomimetics, and recombinant proteins. Despite these significant developments, heparin and heparin-derived drugs have continued to play a major role in the management of thrombotic and cardiovascular disorders.

Development of Generic Low Molecular Weight Heparins: A Perspective

It is clear that the introduction of generic versions of low molecular weight heparins (LMWHs) is inevitable; however, it is important that the generic products are manufactured in strict compliance with the manufacturing specification of the branded product. Furthermore, regulatory agencies should require additional data on the chemical biologic, pharmacologic/toxicologic, and dose-response relationship in specific settings. Although there is strong opposition to stop the introduction of these drugs, their development will reduce cost and permit availability to all patients who need them. Some objective guidelines for the proper development of these drugs are needed. Only expert groups and advisory panels to the regulatory bodies can develop these guidelines.

Differentiation of the low-molecular-weight heparins

The three low-molecular-weight heparins (LMWHs) available in the United States have been extensively evaluated for a wide array of indications. Properties associated with one LMWH cannot be assumed to be the same as those associated with another LMWH, as they are different pharmacologic entities. Therefore, therapeutic interchange of these agents is inappropriate. The pharmacokinetic and pharmacodynamic differences among LMWHs can be explained by comparing methods of preparation, molecular structures, half-lives, antithrombin- and non-antithrombin-mediated actions, effect on thrombus, and dosing interval. The Food and Drug Administration-approved indications and their respective levels of clinical evidence further differentiate these agents. A dichotomy in the results of clinical trials has been observed with the LMWHs. As the LMWHs are distinct compounds that each possess unique pharmacokinetic and pharmacodynamic profiles, treatment decisions should be based on the available safety and efficacy data for each LMWH. Agents should be prescribed only for those indications for which they have been shown to be effective and only at dosages that have been studied.

Applying scientific criteria to therapeutic interchange: a balanced analysis of low-molecular-weight heparins

Under pressure to provide cost-effective healthcare, many healthcare systems have adopted Therapeutic Interchange (TI) programs-the interchange of therapeutically equivalent but chemically unique drugs-to reduce the total cost of therapy without compromising patient care. To be appropriate and feasible, a TI program for any class of drugs must meet certain rigorous criteria and undergo medical, financial, tactical, and legal reviews. Moreover, once a TI program is implemented, a process to monitor its success should be established. Application of the TI criteria to low-molecular-weight heparins (LMWHs) reveals that a blanket TI program for LMWHs does not appear advisable at this time.

Nonclinical safety evaluation of biotechnologically derived pharmaceuticals

The primary objectives of nonclinical safety evaluation for pharmaceutical products are to identify potential target organ toxicity, provide a safe starting dose for clinical trials, and establish dose-response relationships. These objectives do not differ in concept for either small molecular weight compounds or biotechnologically derived pharmaceuticals; they are important for both. The complex structural and biological characteristics of biotechnologically derived pharmaceuticals, however, dictate that different approaches to their safety evaluation are needed. Although their novel mode of production initially raised concerns about their safety, improvements in analytical and manufacturing procedures have largely minimized the perceived risks. It is primarily their exaggerated pharmacodynamic properties that produce the toxicity observed in nonclinical studies. Even though most of these products will require a case-by-case, scientifically based approach, knowledge gained from both nonclinical and clinical evaluation of these novel products have highlighted some general principles with regards to their safety evaluation. These principles include the importance of evaluating species in which the biotechnologically derived pharmaceutical is biologically active, the potential impact of immunogenicity on the interpretation of multiple dose toxicity study results, and the need for both highly sensitive and specific analytical methods to measure their pharmacodynamic properties. An understanding of these principles forms the basis for the development of a scientifically sound nonclinical safety evaluation program.

The economic impact of treating deep vein thrombosis with low-molecular-weight heparin: outcome of therapy and health economy aspects

Subcutaneous low-molecular-weight heparin (LMWH) is at least as safe and effective as classical intravenous heparin therapy for the treatment of proximal vein thrombosis. Anticoagulant monitoring and intravenous administration are not required with LMWH treatment, therefore this therapy may offer economic advantages. An economic evaluation of these therapeutic approaches was performed comparing the costs and effectiveness. The evaluation was aimed at helping decision-makers to maximize the health of the population served, subject to available resources. The American-Canadian Thrombosis Study was a multicentre, randomized, double-blind clinical trial that compared treatment by initial continuous intravenous infusion of heparin (followed by 3 months of warfarin therapy) with a once-daily dose of subcutaneous LMWH, tinzaparin sodium (followed by 3 months of warfarin treatment) in patients with acute proximal deep vein thrombosis. In the LMWH-treated group, the cost incurred for 100 patients was $399,403 (Canadian) or $335,687 (US) with a frequency of objectively documented recurrent venous thromboembolism of 2.8%. In the intravenous heparin-treated group, the cost incurred for 100 patients was $ 414,655 (Canadian) or $ 375,836 (US), with a frequency of objectively documented recurrent venous thromboembolism of 6.9%. These results show a cost saving of $ 15,252 (Canadian) or $ 40,149 (US) with the use of LMWH. Multiple sensitivity analyses did not alter the findings of the study which indicated that LMWH therapy is at least as safe and effective but less costly than intravenous heparin treatment. The potential for outpatient therapy in up to 37% of patients who are receiving LMWH would substantially augment the cost-saving. The cost-effectiveness findings presented in this paper are based on the assumption that all costs are covered by a single payer. Outpatient management in many countries will shift the healthcare costs from the healthcare payer to the patient, increasing the economic burden to the patient.

Heparin and low molecular weight heparin for treatment of acute pulmonary embolism

Pulmonary embolism occurs in more than 175,000 patients each year in the United States. The objectives of treatment are to prevent death from the existing embolus, to prevent death and morbidity from recurrent pulmonary embolism, and to prevent morbidity from recurrent deep-vein thrombosis. For patients with adequate cardiorespiratory reserve, the primary objective is to prevent recurrent pulmonary embolism. Anticoagulant therapy with intravenous unfractionated heparin or subcutaneous low molecular weight heparin followed by oral anticoagulant treatment for at least 3 months is the treatment of choice for most of these patients. Clinical trials indicate that the effectiveness of intravenous heparin depends on achieving an adequate heparin effect (activated partial thromboplastin time above lower limit) during the initial 24 hours. A validated protocol for intravenous heparin should be used to lessen the likelihood of delayed heparinization. Low molecular weight heparin given subcutaneously either once or twice daily is as effective as intravenous heparin for the treatment of patients with deep-vein thrombosis and submassive pulmonary embolism. Low molecular weight heparin enables many patients with uncomplicated deep-vein thrombosis to be treated in an outpatient setting.