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

Hemorrhage induced by antithrombotic agents: new insights from a real-world pharmacovigilance study

BACKGROUND

Hemorrhage represents the most common and serious side effect of antithrombotic agents. Many studies have compared the risk of bleeding between different antithrombotic agents, but analysis of time-to-onset for hemorrhage induced by these drugs is yet sparse.

METHODS

We conducted a retrospective study based on the adverse drug reaction reports on antithrombotic agents collected by the Henan Adverse Drug Reaction Monitoring Center. We assessed the reporting odds ratio to determine the disproportionate reporting signals for bleeding and the Weibull shape parameter was used to evaluate the time-to-onset data.

RESULTS

In the signal detection, crude low molecular weight heparin-hemorrhage was found as a positive signal. The hemorrhage for most antithrombotic agents was random failure profiles. In particular, the hazard of hemorrhage decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole.

CONCLUSION

We found that the risk of bleeding in patients taking Crude low molecular weight heparins was significantly higher compared to other antithrombotic agents, but with a small magnificence, which may be attributed to the severely irrational use of this medication under improper management. Statistics in days, results showed that the risk of bleeding decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole.

Non-Anticoagulant Activities of Low Molecular Weight Heparins-A Review

Low molecular weight heparins (LMWHs) are derived from heparin through chemical or enzymatic cleavage with an average molecular weight (Mw) of 2000-8000 Da. They exhibit more selective activities and advantages over heparin, causing fewer side effects, such as bleeding and heparin-induced thrombocytopenia. Due to different preparation methods, LMWHs have diverse structures and extensive biological activities. In this review, we describe the basic preparation methods in this field and compare the main principles and advantages of these specific methods in detail. Importantly, we focus on the non-anticoagulant pharmacological effects of LMWHs and their conjugates, such as preventing glycocalyx shedding, anti-inflammatory, antiviral infection, anti-fibrosis, inhibiting angiogenesis, inhibiting cell adhesion and improving endothelial function. LMWHs are effective in various diseases at the animal level, including cancer, some viral diseases, fibrotic diseases, and obstetric diseases. Finally, we briefly summarize their usage and potential applications in the clinic to promote the development and utilization of LMWHs.

Biosimilars of low molecular weight heparins: Relevant background information for your drug formulary

Biosimilars of low molecular weight heparins (LMWHs) are more alike the originator than different branded LMWHs. The latter differ largely in molecular weight, anti-FXa/anti-FIIa ratio and antithrombin binding. The Food and Drug Administration and European Medicines Agency guidelines are sufficient for the clinical use of high quality LMWHs. However, the Food and Drug Administration guideline lacks the results of a phase I clinical trial in the approval process. Most information about biosimilars is available for enoxaparin given that many biosimilars of enoxaparin have received market access. The guidelines of many International Thrombosis Societies for LMWH biosimilars are too stringent, not updated and impractical for formulary uptake discussions. This review gives background information on critical factors for the formulary uptake process of LMWHs with special attention for the use of the System of Objectified Judgment Analysis/Infomatrix model.

Systematic literature review of the methodology for developing pharmacotherapeutic interchange guidelines and their implementation in hospitals and ambulatory care settings

PURPOSE

To summarize literature specific to therapeutic interchange (TI) focusing on methodological approaches in order to develop a list of steps that healthcare facilities can consult when developing pharmacotherapeutic interchange guidelines (PTIGs) in hospitals and primary care centers.

METHODS

A search was conducted in PreMEDLINE, Medline, EMBASE, PsycINFO, and the Cochrane Library up to and including December 2015. PRISMA guidelines were used. The inclusion criteria were articles published on TI: methodology, implementation, guidelines, and position statements of scientific societies. Two authors independently reviewed all articles for eligibility and extracted the data.

RESULTS

A total of 102 articles were selected for full-text review; we included three guidelines on how to effect TI, nine position papers of various scientific societies with regard to TI, two articles dealt exclusively about methodology, three articles consisted of recommendations and perspectives on TI, three articles dealt with legal aspects, four articles examined general implementation procedures, two articles were a post-discharge follow-up of patients who had TI, six were surveys referring to TI, and three were articles on the use of TI in ambulatory care The remaining 67 articles focused on therapeutic groups. Study quality was generally low.

CONCLUSIONS

This review identified articles on TI as published guidelines, recommendations, and studies on TI carried out in hospital settings. As a result, eight fundamental steps were established for obtaining adequate results in the development of TI programs.

Efficacy and Safety of a Biosimilar Versus Branded Enoxaparin in the Prevention of Venous Thromboembolism Following Major Abdominal Surgery: A Randomized, Prospective, Single-Blinded, Multicenter Clinical Trial

Several biosimilar versions of enoxaparin are already approved and in use globally. Analytical characterization can establish good quality control in manufacturing, but they may not assure similarity in clinical outcomes between biosimilar and branded enoxaparin. This study evaluated the efficacy and safety of biosimilar Cristália versus branded Sanofi enoxaparin in venous thromboembolism (VTE) prevention in patients undergoing major abdominal surgery at risk for VTE. In this randomized, prospective single-blind study, we compared Cristália enoxaparin (Ce), a biosimilar version, versus branded Sanofi enoxaparin (Se; at a dose of 40 mg subcutaneously per day postoperatively from 7 to 10 days) in 243 patients submitted to major abdominal surgery at risk for VTE for VTE prevention. The primary efficacy outcome was occurrence of VTE or death related to VTE. The principal safety outcomes were a combination of major bleeding and clinically relevant non-major bleeding. Bilateral duplex scanning of the legs was performed from days 10 to 14, and follow-ups were performed up to 60 days after surgery. The incidence of VTE was 4.9% in the Cristália group and 1.1% in the Sanofi group (absolute risk difference = 3.80%, 95% confidence interval [CI]: −1.4%-9.0%) yielding noninferiority since the 95% CI does not reach the prespecified value Δ = 20%. Clinically significant bleeding occurred in 9.9% in the Cristália group and in 5.5% in the Sanofi group (n.s. ). In conclusion, this study suggests that 40 mg once daily of Ce, a biosimilar enoxaparin, is as effective and safe as the branded Sanofi enoxaparin in the prophylaxis of VTE in patients submitted to major abdominal surgery at risk for VTE.

Pharmacologic and Liability Considerations of Therapeutic Interchange with Low-Molecular-Weight Heparins

Therapeutic interchange (TI), a formulary management process, is used by health care systems to help contain medication costs. A scientifically defensible and pharmacoeconomically beneficial TI program adheres to rigorous criteria enforced by an institution's Pharmacy and Therapeutics Committee. In situations where adherence to essential criteria is not mandated, TI may not produce the intended clinical and economic outcomes, and in practice may have legal implications. Appropriate application of TI has been described within the position statements of certain health care organizations and associations. Due to the high cost and frequent use of low-molecular-weight heparins (LMWHs), health care institutions have identified this pharmacologic class as a potential target for TI. Currently, the application of the TI process to LMWHs is questionable. This paper reviews the TI process and explores its controversial role in the formulary management of LMWHs.

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.

Bioengineered human heparin with anticoagulant activity

Heparin is a carbohydrate anticoagulant used clinically to prevent thrombosis, however impurities can limit its efficacy. Here we report the biosynthesis of heparin-like heparan sulfate via the recombinant expression of human serglycin in human cells. The expressed serglycin was also decorated with chondroitin/dermatan sulfate chains and the relative abundance of these glycosaminoglycan chains changed under different concentrations of glucose in the culture medium. The recombinantly expressed serglycin produced with 25mM glucose present in the culture medium was found to possess anticoagulant activity one-seventh of that of porcine unfractionated heparin, demonstrating that bioengineered human heparin-like heparan sulfate may be a safe next-generation pharmaceutical heparin.

Product Individuality of Commercially Available Low-Molecular-Weight Heparins and Their Generic Versions: Therapeutic Implications

The currently available brand-name low-molecular-weight heparins (LMWHs) in the United States include dalteparin (Pfizer), enoxaparin (Aventis), and tinzaparin (Pharmion). Other products available, in Europe, include certoparin (Novartis), reviparin (Abbott), nadroparin (GlaxoSmithkline), and parnaparin (Alpha-Wasserman). Each of these LMWHs has a characteristic molecular weight profile and biological activity in terms of an anti-FXa and anti-FIIa potency. The mean molecular weight of these drugs ranges from 4.0 kDa to 7.0 kDa and the anti-FXa:anti-FIIa ratio ranges from 1.5 to 3.5. These agents may also be characterized by the presence of specific chemical end groups such as 2-O-sulfo-4-enepyranosuronic acid at the nonreducing terminus (enoxaparin) or 2,5-anhydro-D-mannose at the reducing terminus (dalteparin). Further, the component oligosaccharide chains exhibit product-specific distribution profiles. It is now widely accepted that individual LMWHs are chemically unique agents and cannot be interchanged therapeutically. Each commercial LMWH has been individually developed for specific clinical indications, which are dose and product dependent. Recently, several generic LMWHs have become available in India (Cutenox and Markaparin) and South America (dilutol, clenox, dripanina), and three companies have filed for regulatory approval of a generic version of enoxaparin in the United States. As the primary aim of a generic drug is to reduce cost without compromising patient care, a generic drug is required to be chemically and biologically equivalent to the pioneer drug. Because LMWHs represent complex natural mucopolysaccharide drugs that have undergone chemical and enzymatic modifications, physicochemical and biological information in addition to molecular weight and anti-FXa:anti-FIIa ratio should be used to determine generic equivalency to the branded drug. We have utilized a previously reported approach to systematically compare three generic versions of enoxaparin obtained from India and Brazil with the branded enoxaparin (Lovenox) available in the United States. Testing included molecular and structural profiling, evaluation in clot-based and amidolytic anti-FXa and anti-FIIa assays, and heparinase-I digestion profiles. While the molecular profiles (4.8 ± 1.8kD) and anticoagulant potencies as determined by activated partial thromboplastin time (APTT) were comparable for all four agents, the generic products showed variations in the thrombin time (TT) and Heptest assays. Two generic and the branded enoxaparin were readily digested by heparinase-I, losing most of their anticoagulant activity, but one generic product resisted digestion. This may have been due to a unique structural feature in this product. These studies show that, while generic LMWHs may exhibit acceptable molecular weight and anti-FXa profiles, they can exhibit assay-based differences and digestion profiles. Testing in animal models to determine safety, efficacy, and pharmacodynamic parameters may be important to verify equivalence. In order to assure that the generic LMWHs are equivalent to branded LMWHs such that equivalent clinical results are obtained, there is a need to develop clear stepwise guidelines that will establish equivalency in terms of physical, chemical, biochemical, pharmacokinetic, and pharmacodynamic properties for these anticoagulant drugs.

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.

Low-molecular-weight heparin biosimilars: potential implications for clinical practice. Australian Low-Molecular-Weight Heparin Biosimilar Working Group (ALBW)

A working group of clinicians and scientists was formed to review the clinical considerations for use of low-molecular-weight heparin (LMWH) biosimilars. LMWH are biological molecules of significant complexity; the full complexity of chemical structure is still to be elucidated. LMWH biosimilars are products that are biologically similar to their reference product and rely on clinical data from a reference product to establish safety and efficacy. The complex nature of LMWH molecules means that it is uncertain whether a LMWH biosimilar is chemically identical to its reference product; this introduces the possibility of differences in activity and immunogenicity. The challenge for regulators and clinicians is to evaluate the level of evidence required to demonstrate that a LMWH is sufficiently similar to the reference product. The consensus opinion of the working group is that prior to clinical use a LMWH biosimilar should have proven efficacy and safety, similar to the reference product with prospective studies, which should be confirmed with a proactive post-marketing pharmacovigilance programme.

Therapeutic Interchange of Parenteral Anticoagulants: Challenges for Pharmacy and Therapeutics Committees

This is a review of key factors for pharmacy and therapeutics committees to consider when developing a therapeutic interchange (TI) program for venous thromboembolism (VTE) prophylaxis. Recent patient safety initiatives aimed at reducing the incidence of hospital-acquired VTE may increase the prescribing of thromboprophylactic agents recommended in VTE management guidelines. As a result, more pharmacy and therapeutics committees may consider TI programs for parenteral anticoagulants. However, the TI of anticoagulants appears challenging at this time. Firstly, the therapeutic equivalence of the commonly prescribed parenteral anticoagulants, enoxaparin, dalteparin and fondaparinux, has not been established. Secondly, because of the wide range of clinical indications for these anticoagulants, a blanket agent-specific TI program could lead to off-label use. Use of an indication-specific TI program could be difficult to manage administratively, and may cause prescribing confusion and errors. Thirdly, careful dosing and contraindications of certain parenteral anticoagulants in special patient populations, such as those with renal impairment, further impact the suitability of these agents for inclusion in TI programs. Finally, although TI may appear to offer lower drug-acquisition costs, it is important to determine its effect on all cost parameters and ultimately ensure that the care of patients requiring VTE prophylaxis is not compromised.

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.

Anticoagulation therapy for prevention and treatment of venous thromboembolic events in cancer patients: a review of current guidelines

Cancer patients in general have a high risk of venous thromboembolic events (VTE) driven not only by patient-related risk factors, but also risk factors related to the disease and anti-cancer therapies. Cancer patients with documented VTE have a notably worse outcome than non-cancer VTE patients. Since VTE is a highly preventable condition, it is striking that large surveys have shown significant underuse of VTE prophylaxis in surgical cancer patients and in medical cancer patients in particular. Recently, guidelines have been issued from European and American medical oncology societies and organizations for identification of cancer patients at risk, and the guidelines give recommendations for treatment of individual groups of cancer patients. This review summarizes the recommendations for VTE prophylaxis and treatment from the recent guidelines and reviews some outstanding issues in VTE prophylaxis and treatment of cancer patients.

Proton pump inhibitors for acid suppression in the intensive care unit: Formulary considerations

PURPOSE

The rationale for limiting the proton pump inhibitor (PPI) products included in an institutional formulary, factors to consider when making formulary decisions about PPI products, the results and limitations of cost-effectiveness analyses of PPI therapy in critically ill patients, the role of clinical practice guidelines in improving PPI use in the intensive care setting, and how these guidelines can be developed are discussed.

SUMMARY

Therapeutic interchange may make it possible to limit the number of PPI products included in the formulary and reduce costs without compromising the efficacy or safety of drug therapy. The results of studies comparing the pharmacokinetics, pharmacodynamics, and efficacy of different PPI dosage forms and routes of administration; practical considerations; safety; and costs are among the factors to consider when making formulary decisions. Some of the newer oral PPI products offer advantages over older ones in improved palatability and ease of preparation, storage, and administration. The cost-effectiveness of intravenous (i.v.) PPIs for preventing the recurrence of peptic ulcer bleeding has been demonstrated, but the cost-effectiveness of oral therapy for this indication and both oral and i.v. therapy for preventing stress-related mucosal bleeding has not been well established.

CONCLUSION

Intravenous PPIs are cost-effective for patients at risk for the recurrence of peptic ulcer bleeding. The introduction of new oral PPI products that can be administered as a suspension has expanded the therapeutic options for critically ill patients. The use of clinical practice guidelines can optimize the use of PPIs in the intensive care setting.

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.

Survey of pharmacists' and physicians' perceptions of therapeutic interchange

Therapeutic interchange has long been an integral part of drug formulary management, but physicians' and pharmacists' attitudes toward such programs are relatively unknown. This survey was undertaken to determine pharmacists' attitudes, physicians' potential response to a hypothetical interchange, and how well pharmacists predicted physicians' responses. A survey that described a drug interchange program and several potential responses to the proposed switch was provided to 300 staff physicians at a 512-bed community facility in southwest Florida; the survey was also mailed to pharmacy directors or clinical pharmacy coordinators at 42 southwest Florida hospitals. Responses were obtained from 98 physicians and 95 pharmacists. Most physicians would not cooperate with an interchange if they were not familiar with the proposed drug; 16% would continue to prescribe the original drug, knowing that the new agent would be provided; and 58% would switch to another agent with which they had clinical experience. Only 26% of physicians would follow the interchange program. In contrast, 48% of pharmacists believed that physicians would continue to order the original therapy, 32% believed that physicians would order the new agent, and only 20% believed that physicians would switch to an alternative drug (P<.005 vs physician responses). Clearly, pharmacists' expectations of physicians' response to a therapeutic interchange differ significantly from the physicians' expected behavior. This difference has potentially important implications for actual versus projected cost savings of therapeutic interchange.

Choice of agents to limit the coagulation cascade in acute coronary syndromes

Arterial thrombosis, the predominant event in acute coronary syndromes (ACS), is the end-result of endothelial cell dysfunction, impaired vascular thromboresistance, and sudden atheromatous plaque disruption, each occurring amid a backdrop of inflammation and inflammatory mediators. Because the contribution of individual coagulation proteins to coronary arterial thrombosis varies from modest to marked, selective pharmacologic targeting is both pathobiologically sound and clinically preferred. The development of second-generation anticoagulants with broadened therapeutic windows represents an advance in the management of ACS.