Biosimilars, sometimes referred to as biogenerics, are highly similar versions of biologics, those medicines made from living microorganisms found in plant or animal cells. The term “generic” refers only to traditional (small molecule) drugs that are bioequivalent to an already approved small molecule drug , according to the U.S. Food and Drug Administration (FDA).
Most biologics are very large, complex molecules or mixtures of molecules. Biologics are used to treat cancer, Alzheimer's disease, multiple sclerosis, HIV/AIDS and other serious diseases. Currently, no biosimilar has been approved for the U.S. market.
It's estimated that about 150 biologic drugs are currently approved for use, many of which have lost patent protection. Biosimilar versions of biologics are now available in 11 countries. FDA's counterpart, the European Medicines Agency (EMA) approved a biosimilar approval process in 2004. The FDA is currently holding hearings and gathering input for development of a biosimilar approval process and it's likely to have many of the provisions found in EMA's approval pathway.
As of November 2011, the FDA had not yet finalized the details of the process. "Because biological products are complex products, the development and approval of biosimilars is a complicated and challenging process," according to the agency's website. "The Agency understands that several companies are developing biosimilar products and may submit applications for licensure under the new law." Some of the key issues to be determined include interchangeability, comparative effectiveness studies, exclusivity and user fees.
Writing in Nature, author Heidi Ledford described the challenge of replicating a biologic drug. "Unlike the relatively simple construction of a small-molecule drug, making a biosimilar is more like placing a complicated family recipe in the hands of a new chef. The overall result may be roughly the same, but it is not exactly how mother used to make it — and it may not precisely match the safety and therapeutic effects of the original."
During the health reform debate of 2009, biologic drug companies won the right to a 12-year exclusivity period for biosimilars, more than twice that of the 5-year exclusivity period granted to makers of traditional chemical drugs.
The health reform legislation which was signed into law by President Obama in March 2010 defined biosimilar as a biological product that is demonstrated to be “highly similar” to a previously approved biological product. The law also authorized the FDA to create an abbreviated approval pathway for biosimilars.
There is significant support for faster approval of biosimilars in order to save costs. Treatment with biologic drugs can range from $100,000 to $300,000 a year. The Generic Pharmaceutical Association (GPhA) says evidence from several studies suggest that increased entry of biosimilars into the market could save $42 billion to $108 billion over a 10-year period.
However, the Biotechnology Industry Organization (BIO) has refuted studies by Express Scripts and the Pharmaceutical Care Management Association that showed a potential cost savings from more rapid adoption of biosimilar drugs. BIO said the studies contained inaccurate estimations or relied on flawed calculations.
Both innovator drug companies and generic manufacturers have biosimilar drugs in late-stage development, or have announced plans to invest in biosimilar research and development. Among those that have invested in biosimilar drug discovery are Merck & Co., Dr. Reddy's Laboratories, Ranbaxy, Teva Pharmaceuticals, Sandoz International, and Watson Pharmaceuticals.