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.

Synthetic oligosaccharides can replace animal-sourced low-molecular weight heparins

Low-molecular weight heparin (LMWH) is used clinically to treat clotting disorders. As an animal-sourced product, LMWH is a highly heterogeneous mixture, and its anticoagulant activity is not fully reversible by protamine. Furthermore, the reliability of the LMWH supply chain is a concern for regulatory agencies. We demonstrate the synthesis of heparin dodecasaccharides (12-mers) at the gram scale. In vitro experiments demonstrate that the anticoagulant activity of the 12-mers could be reversed using protamine. One of these, labeled as 12-mer-1, reduced the size of blood clots in the mouse model of deep vein thrombosis and attenuated circulating procoagulant markers in the mouse model of sickle cell disease. An ex vivo experiment demonstrates that the anticoagulant activity of 12-mer-1 could be reversed by protamine. 12-mer-1 was also examined in a nonhuman primate model to determine its pharmacodynamic parameters. A 7-day toxicity study in a rat model showed no toxic effects. The data suggest that a synthetic homogeneous oligosaccharide can replace animal-sourced LMWHs.

Update on Brazilian biosimilar enoxaparins

INTRODUCTION

Brazil is among the first countries approving the commercialization and clinical use of biosimilar enoxaparins. Our research group has performed quality control assessments of these drugs over the last decade. Areas covered: We have not found noticeable differences between Brazilian biosimilar enoxaparins and the original product regarding their physicochemical properties, disaccharide composition, anticoagulant activity, bioavailability and safety. Expert commentary: In spite of clinical and pharmacological advantages of enoxaparin, subcutaneous formulations of unfractionated heparin are employed by the Brazilian public health system for prevention and treatment of thromboembolism. The underuse of both original and biosimilar enoxaparins in Brazil directly correlates with their high cost.

Comparative studies on biological activity of generic and branded enoxaparin in vivo and vitro

As per US Food and Drug Administration (FDA) requirement, the study was designed to conduct the fourth and fifth criteria of Abbreviated New Drug Application to demonstrate equivalence of generic and branded Enoxaparin in vivo and vitro.Pharmacodynamic behavior of branded and generic Enoxaparin was compared in a parallel study in rats based upon measurement of anti-FXa and anti-FIIa profiles. Blood samples collected at baseline and at 0.5, 1, 2, 4, 6, 8, 12 and 24 h postsubcutaneous administration of six batches of Lovenox and nine batches of generic Enoxaparin were evaluated for anti-FXa and anti-FIIa using chromogenic substrate method. Anti-FXa, Anti-FIIa, activated partial thromboplastin time (APTT), and Heptest prolongation time were conducted in vitro as per the United States Pharmacopeia method. Pharmacodynamics parameters were obtained including peak effect (anti-FXamax, anti-FIIamax), area under the effect curve (AUEC0-T and AUEC0-∞), Tmax, and T1/2.Pharmacokinetic differences were not observed using anti-FXa or anti-FIIa. No statistically significant differences were observed between branded and generic Enoxaparin either in vitro anti-FXa, anti-FIIa, APTT, or Heptest assay.It can be concluded that they are bioequivalent in anticoagulant activity tested in vivo and vitro.

Update on the safety and bioequivalence of biosimilars - focus on enoxaparin

Generic forms of chemically-derived drugs must exhibit chemical identity and be bioequivalent in healthy human subjects. The use of generic drugs results in a considerable savings of healthcare expenditures. Biologic drugs are produced in living systems or are derived from biologic material and extend beyond proteins to include antibodies, polysaccharides, polynucleotides, and live viral material. Such drugs pose a challenge to characterize as they tend to be larger in size than chemically-derived drugs, can exhibit a variety of post-translational modifications, and can have activities that are dependent on specific conformations. Biosimilars are not true generics, but rather, exhibit a high degree of similarity to the reference product and are considered to be biologically and clinically comparable to the innovator product. Therefore, the development process for biosimilars is more complex than for a true generic. Guidance is now available from the US Food and Drug Administration and from the European Medicines Agency for the development of biosimilar drugs. Biosimilar drugs are expected to have a major impact in the management of various diseases in coming years.

Evaluating the inter and intra batch variability of protein aggregation behaviour using Taylor dispersion analysis and dynamic light scattering

Biosimilar pharmaceuticals are complex biological molecules that have similar physicochemical properties to the originator therapeutic protein. They are produced by complex multi-stage processes and are not truly equivalent. Therefore, for a biosimilar to be approved for market it is important to demonstrate that the biological product is highly similar to a reference product. This includes its primary and higher order structures and its aggregation behaviour. Representative lots of both the proposed biosimilar and the reference product are analysed to understand the lot-to-lot variability of both drug substances in the manufacturing processes. Whilst it is not easy to characterise every variation of a protein structure at present additional analytical technologies need to be utilised to ensure the safety and efficacy of any potential biosimilar product. We have explored the use of Taylor dispersion analysis (TDA) to analyse such batch to batch variations in the model protein, bovine serum albumin (BSA) and compared the results to that obtained by conventional dynamic light scattering analysis (DLS). Inter and intra batch differences were evident in all grades of BSA analysed. However, the reproducibility of the TDA measurements, enabled the stability and reversibility of BSA aggregates to be more readily monitored. This demonstrates that Taylor dispersion analysis is a very sensitive technique to study higher order protein states and aggregation. The results, here, also indicate a correlation between protein purity and the physical behaviour of the samples after heat shocking. Here, the protein with the highest quoted purity resulted in a reduced increase in the measured hydrodynamic radius after heat stressing, indicating that less unfolding/aggregation had occurred. Whilst DLS was also able to observe the presence of aggregates, its bias towards larger aggregates indicated a much larger increase in hydrodynamic radii and is less sensitive to small changes in hydrodynamic radii. TDA was also able to identify low levels of larger aggregates that were not observed by DLS. Therefore, given the potential for immunogenicity effects that may result from such aggregates it is suggested that TDA may be suitable in the evaluating detailed batch to batch variability and process induced physical changes of biopharmaceuticals and biosimilars.