Rheumatoid arthritis is the most common inflammatory form of arthritis and affects approximately two million Americans.
Until about seventeen years ago, the primary treatment modalities available for rheumatoid arthritis allowed some control of disease but patients rarely went into complete remission.
Biologic drugs- protein-based medicines that target specific abnormalities in the immune system- revolutionized the treatment of rheumatoid arthritis.
Their effectiveness has allowed rheumatologists to not only control rheumatoid disease better but has even permitted many patients to achieve true remission.
Unfortunately, a major limiting factor has been the high price tag associated with these drugs with costs ranging anywhere from $1500 to $2200 per month.
The patents on a few of these drugs may be expiring soon and some biotech and pharmaceutical companies are eager to develop biosimilar drugs. A biosimilar is not a generic drug. It is defined by the FDA as a drug that is "highly similar or interchangeable with an already approved biologic drug."
Biologic compounds are very complicated. They are large molecule drugs. And that is why they differ from standard "pills." An example would be aspirin which is considered a small molecule drug. It measures 180 daltons and has 21 atoms. It has little ability to initiate an immune response and remains relatively stable over time.
In contrast, a typical monoclonal antibody biologic drug measures 150,000 daltons, contains 20,000 atoms, degrades over time, and has the ability to generate a significant immune response. Thus, the production of a biologic is an inherently unstable situation requiring special handling and storage.
A biologic medicine begins with a unique and proprietary cell line and goes through a number of complicated steps to make sure the end product is pure.
A company trying to make a biosimilar has to start with the end product and work backward. The sequence of amino acids that makes up the "guts" of an effective biologic medicine is what the manufacturer of a "copy" must produce.
The manufacturing process is also one that needs to adhere closely to that of the original drug. While not all steps are identical here, the important ones need to be.
Because of these differences, biosimilar drugs will need to undergo clinical trial testing to ensure they function as well as the drug they are supposed to be "copies" of.
According to the FDA, "a biosimilar drug is expected to produce the same clinical result in any given patient."
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