Current Issue : October - December Volume : 2011 Issue Number : 4 Articles : 8 Articles
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The evidence for conversion from brand name to generic equivalent cyclosporine is conflicting. Cyclosporine is a narrow therapeutic-range drug for which small variations in exposure may have severe clinical consequences for transplant patients. There is currently a lack of comparative outcome data relating to the pharmacokinetics of the reference formulation, Neoral, and generic formulations in transplant recipients. A major common concern is the potential inability to attain similar trough levels, an issue that can be easily corrected by ongoing therapeutic drug monitoring to ensure that the new steady state falls within an intended target range. Prospective clinical studies investigating the efficacy and safety of generic formulations in both de novo and long-term transplant patients are also awaited. Until further evidence is available on the conversion of transplant patients to or between generic formulations of cyclosporine, any transfer to a different cyclosporine formulation should be undertaken with close supervision. The best available information to date, however, does not support the frequently held but unsubstantiated belief that generic preparations of immunosuppressive drugs are not as effective as brand names or that conversion from brand to generic is associated with significant danger. This paper attempts to initiate a discussion of these issues....
Being protein function a conformation-dependent issue, avoiding aggregation during production is a major challenge in biotechnological processes, what is often successfully addressed by convenient upstream, midstream or downstream approaches. Even when obtained in soluble forms, proteins tend to aggregate, especially if stored and manipulated at high concentrations, as is the case of protein drugs for human therapy. Post-production protein aggregation is then a major concern in the pharmaceutical industry, as protein stability, pharmacokinetics, bioavailability, immunogenicity and side effects are largely dependent on the extent of aggregates formation. Apart from acting at the formulation level, the recombinant nature of protein drugs allows intervening at upstream stages through protein engineering, to produce analogue protein versions with higher stability and enhanced therapeutic values....
As more biologic products are going off patent protection, the development of follow-onbiologics (biosimilars) products has received much attention from both biotechnology industry and the regulatory agencies. Unlike traditional small-molecule (chemical) drug products, the development of biologic products is very different and variable with respect to the manufacturing process and environment. The complexity and heterogeneity of the molecular structure, complicated manufacturing process, different analytical methods, and possibility of severe immunogenicity reactions make quantitative evaluation of follow-on biologics a great challenge to both scientific community and regulatory agencies. In this article, an overview of current criteria, study design, and statistical methods for quantitative evaluation of bioequivalence for the traditional small molecule generic drug products and biosimilarity for biosimilars products is provided. In addition, a general approach for development of a biosimilarity index based on the concept of reproducibility probability for quantitative evaluation of bioequivalence/biosimilarity is proposed. Some scientific factors and practical issues are also discussed....
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