What is a biological product?
According to the U.S. Federal Code of Regulations (CFR), the definition of a biologic is “any virus, therapeutic serum, toxin, antitoxin, or analogous product applicable to the prevention, treatment, or cure of disease or injuries of man.”

Biological products can include a wide range of products including vaccines, blood and blood components, allergenics, somatic cells, gene therapy, tissues, and proteins. Unlike most traditional, small-molecule prescription drugs that are made through chemical processes, biological products are generally made from human and/or animal materials. Biological products are usually larger than and have a more complex structure than small-molecule prescription drugs. Such products may be manufactured through biotechnology, derived from natural sources, or, in some cases, produced synthetically.

Most, but not all, biological products are licensed under the Public Health Service Act (PHS Act). Small-molecule prescription drugs are approved under the Food, Drug and Cosmetic Act (the FD&C Act).t

What is a biosimilar?
A biosimilar is a biological product that is highly similar to a U.S.-licensed reference biological product notwithstanding minor differences in clinically inactive components, and for which there are no clinically meaningful differences between the biological product and the reference product in terms of the safety, purity, and potency of the product.

Why does it matter what law a medication is approved under?
The FD&C Act provides a pathway for drug manufacturers to rely on the agency’s previous findings that the reference listed drug, already approved under the Act, is safe and effective. These are known as generic drugs, which must have the same active ingredient(s), previously approved conditions of use, dosage form, strength, route of administration, and (with certain exceptions) labeling as the reference listed drug. The generic drug must also be bioequivalent to the brand name drug.

Until the passage of the Affordable Care Act in March 2010, the PHS Act did not have similar provisions to the FD&C Act that allow licensure of biological products based on comparison to already licensed biological products. The Biologics Price Competition and Innovation Act of 2009 (the BPCI Act) allows for an abbreviated licensure pathway for biological products that are “biosimilar” to already licensed biological products that are currently on the U.S. market.

Are biosimilars generic versions of biological products?
No. The word “generic” applies only to small-molecule drugs that are the same as, and bioequivalent to, an already-approved small-molecule drug regulated under the FD&C Act.

Will biosimilars be dispensed in place of the biological product they have been compared to in every situation?
Only if they are interchangeable. Biosimilar biological products cannot be dispensed in place of another biological product unless a physician or other healthcare professional prescribes the biosimilar product. However, biological products that are “interchangeable” will be able to be substituted with certain biological products, as described below.

An “interchangeable” biological product is biosimilar to the reference product, and can be expected to produce the same clinical result as the reference product in any given patient. If administered more than once to an individual (as many biological products are), the risk in terms of safety or diminished efficacy of alternating or switching between use of the biological product and the reference product will not be greater than the risk of using the reference product without such alternation or switch.

Once determined “interchangeable” two biological products will thus be able to be substituted for each other (i.e., interchanged) by a pharmacist without the intervention of the health care provider.

Pharmacists will be responsible for knowing which biological products are interchangeable and which will require prescriber prescription before substitution.

Are biosimilars available now?
To date, FDA has not approved a biological product as biosimilar or interchangeable. Since passage of the Affordable Care Act in 2010, however, FDA has been establishing standards for licensure to ensure the safety and effectiveness of biosimilars. Because biological products are complex products, the development and approval of biosimilars is a complicated and challenging process. The Agency understands that several companies are developing biosimilar products and may submit applications for licensure under the new law. Scientists, clinicians, and other personnel at FDA are currently working out the details of the review and licensure process. It is not yet known when the first biosimilar will be on the U.S. market.

source: FDA