Biosimilar
Encyclopedia
Biosimilars or follow-on biologics
Biologics
A biologic is a medicinal product such as a vaccine, blood or blood component, allergenic, somatic cell, gene therapy, tissue, recombinant therapeutic protein, or living cells that are used as therapeutics to treat diseases...

are terms used to describe officially-approved subsequent versions of innovator biopharmaceutical
Biopharmaceutical
Biopharmaceuticals are medical drugs produced using biotechnology. They include proteins , nucleic acids and living microorganisms like virus and bacteria where the virulence of viruses and bacteria is reduced by the process of attenuation, they can be used for therapeutic or in vivo diagnostic...

 products made by a different sponsor following patent and exclusivity expiry on the innovator product. Biosimilars are also referred to as subsequent entry biologics (SEBs) in Canada. Reference to the innovator product is an integral component of the approval.

Unlike the more common small-molecule
Small molecule
In the fields of pharmacology and biochemistry, a small molecule is a low molecular weight organic compound which is by definition not a polymer...

 drugs, biologics generally exhibit high molecular complexity, and may be quite sensitive to changes in manufacturing processes. Follow-on manufacturers do not have access to the originator's molecular clone and original cell bank, nor to the exact fermentation and purification process, nor to the active drug substance. They do have access to the commercialized innovator product. Differences in impurities and/or breakdown products can have serious health implications. This has created a concern that copies of biologics might perform differently than the original branded version of the product. Consequently only a few subsequent versions of biologics have been authorized in the US through the simplified procedures allowed for small molecule generics
Generic drug
A generic drug is a drug defined as "a drug product that is comparable to brand/reference listed drug product in dosage form, strength, route of administration, quality and performance characteristics, and intended use." It has also been defined as a term referring to any drug marketed under its...

, namely Menotropins (January 1997) and Enoxaparin (July 2010), and a further eight biologics through the 505(b)(2) pathway.

Approval processes

The European regulatory authorities led with a specially adapted approval procedure to authorize subsequent versions of previously approved biologics, termed "similar biological medicinal products" - often called biosimilars for short. This procedure is based on a thorough demonstration of "comparability" of the "similar" product to an existing approved product. In the US the Food and Drug Administration (FDA) held that new legislation was required to enable them to approve biosimilars to those biologics originally approved through the PHS Act pathway. Additional Congressional hearings have been held,. On March 17, 2009, the Pathway for Biosimilars Act was introduced in the House. Full text available or see the Library of Congress website and search H.R. 1548. Since 2004 the FDA has held a series of public meetings on biosimilars.

The FDA gained the authority to approve biosimilars (including interchangeable that are substitutable with their reference product) as part of the Patient Protection and Affordable Care Act signed by President Obama on March 23, 2010 - none have yet been approved. The FDA has previously approved biologic products using comparability, for example, Omnitrope in May 2006, but this like Enoxaparin was also to a reference product, Genotropin, originally approved as a biologic drug under the FD&C Act ) .

Background

Cloning of human genetic material and development of in vitro biological production systems has allowed the production of virtually any recombinant DNA
Recombinant DNA
Recombinant DNA molecules are DNA sequences that result from the use of laboratory methods to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in biological organisms...

 based biological substance for eventual development of a drug. Monoclonal antibody technology combined with recombinant DNA technology has paved the way for tailor-made and targeted medicines. Gene-
Gene therapy
Gene therapy is the insertion, alteration, or removal of genes within an individual's cells and biological tissues to treat disease. It is a technique for correcting defective genes that are responsible for disease development...

 and cell-based
Cell therapy
Cell therapy describes the process of introducing new cells into a tissue in order to treat a disease. Cell therapies often focus on the treatment of hereditary diseases, with or without the addition of gene therapy...

 therapies are emerging as new approaches.

Recombinant therapeutic proteins are of a complex nature (composed of a long chain of amino acids, modified amino acids, derivatized by sugar moieties, folded by complex mechanisms). These proteins are made in living cells ( bacteria, yeast, animal or human cell lines). The ultimate characteristics of a drug containing a recombinant therapeutic protein are to a large part determined by the process through which they are produced: choice of the cell type, development of the genetically modified cell for production, production process, purification process, formulation of the therapeutic protein into a drug.

After the expiry of the patent of approved recombinant drugs (e.g. insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....

, human growth hormone
Growth hormone
Growth hormone is a peptide hormone that stimulates growth, cell reproduction and regeneration in humans and other animals. Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by the somatotroph cells within the lateral wings of the anterior...

, interferons, erythropoietin
Erythropoietin
Erythropoietin, or its alternatives erythropoetin or erthropoyetin or EPO, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production...

, and more) any other biotech company can "copy" and market these biologics
Biologics
A biologic is a medicinal product such as a vaccine, blood or blood component, allergenic, somatic cell, gene therapy, tissue, recombinant therapeutic protein, or living cells that are used as therapeutics to treat diseases...

 (thus called biosimilars).

However, because no two cell lines, developed independently, can be considered identical, biotech medicines cannot be fully copied. The European Medicines Agency
European Medicines Agency
The European Medicines Agency is a European agency for the evaluation of medicinal products. From 1995 to 2004, the European Medicines Agency was known as European Agency for the Evaluation of Medicinal Products.Roughly parallel to the U.S...

, EMEA, has recognized this fact, which has resulted in the establishment of the term "biosimilar" in recognition that, whilst biosimilar products are similar to the original product, they are not exactly the same.
Small distinctions in the cell line, in the manufacturing process or in the surrounding environment can make a major difference in side effects observed during treatment, i.e. two similar biologics can trigger very different immunogenic response. Therefore, and unlike chemical pharmaceuticals, substitution between biologics, including biosimilars, can have clinical consequences and does create putative health concerns.

Biosimilars are subject to an approval process which requires substantial additional data to that required for chemical generics, although not as comprehensive as for the original biotech medicine. However, the safe application of biologics is also dependent on an informed and appropriate use by healthcare professionals and patients. Introduction of biosimilars also requires a specifically designed pharmacovigilance
Pharmacovigilance
Pharmacovigilance is the pharmacological science relating to the detection, assessment, understanding and prevention of adverse effects, particularly long term and short term side effects of medicines...

 plan. It is difficult and costly to recreate biologics because the complex proteins are derived from living organisms that are genetically modified. In contrast, small molecule drugs made up of a chemically based compound can be easily replicated and are considerably less expensive to reproduce. In order to be released to the public, biosimilars must be shown to be as close to identical to the parent biological product based on data compiled through clinical, animal and analytical studies. The results must demonstrate that they produce the same clinical results and are interchangeable with the referenced FDA licensed biological product already on the market.

, ambiguities concerning naming, regional differences in prescribing practices, and regional differences in legally-defined rules with respect to substitution are important points that still need to be resolved to ensure a safe use of biosimilars.

BPCI Act

The Biologics Price Competition and Innovation Act of 2009 (BPCI Act) was originally sponsored and introduced on June 26, 2007 by Senator Edward Kennedy (D-MA). It was formally passed under the Patient Protection and Affordable Care Act
Patient Protection and Affordable Care Act
The Patient Protection and Affordable Care Act is a United States federal statute signed into law by President Barack Obama on March 23, 2010. The law is the principal health care reform legislation of the 111th United States Congress...

 (PPAC Act), signed into law by President Barack Obama on March 23, 2010. The BPCI Act was an amendment to the Public Health Service Act (PHS Act) to create an abbreviated approval pathway for biological products that are demonstrated to be highly similar (biosimilar) to a Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...

 (FDA) approved biological product. The BPCI Act is similar, conceptually, to the Drug Price Competition and Patent Term Restoration Act of 1984 (also referred to as the "Hatch-Waxman Act") which created biological drug approval through the Federal Food, Drug, and Cosmetic Act (FFD&C Act). The BPCI Act aligns with the FDA's longstanding policy of permitting appropriate reliance on what is already known about a drug, thereby saving time and resources and avoiding unnecessary duplication of human or animal testing.

Data exclusivity

Data exclusivity is an important piece of the amendment in the Patient Protection and Affordable Care Act for biosimilars. It is the period of time between FDA approval and an abbreviated filing for a biosimilar on the original producer's data. Data exclusivity is designed to preserve innovation and recognize the long, costly, and risky process involved while the innovator waits to gain FDA approval. The time allowed for data exclusivity is critical for the future of biologics. A number of provisions for data exclusivity in recent legislative proposals ranged up to 14 years, however, the passing of the PPAC Act guarantees a 12 year time period from the time of FDA approval. This is supposed to compensate for perceived shortcomings in patent protection for biologics. Data exclusivity extends from the date of product approval, and this protection period runs concurrently with any remaining patent term protection for the biologic. That is to say, data exclusivity provides additional protection to the innovator when the remaining patent length is shorter than the data exclusivity period at the time of approval (which can occur due to lengthy pre-clinical and clinical research required to obtain FDA approval), or to the extent that the patent term is circumvented by a biosimilar prior to its expiry.
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