Is there a difference? Somewhat.
Biological drugs, or biologics, are a class of drugs that are produced using a microorganism, plant cell, or animal cell. They differ from “small molecule” drugs like aspirin because they are generally larger and more complex.
Biologics have been used in cancer treatment since the 1980s. Immunotherapy is one type. It helps the body’s own immune system fight cancer cells. Others can slow tumor growth or help the body recover from other cancer treatments.
A biologic is produced by growing copies of specially engineered living cells. In a controlled environment, the cells develop proteins. This can take several weeks. The proteins are extracted and purified to produce the final drug, which is highly complex. A small-molecule drug like aspirin can consist of as few as 21 atoms. Biologics can consist of over 25,000 atoms.
Because a biologic uses living cells, there are slight variations in each batch. The manufacturing company uses significant resources to maintain consistency. The entire process is regulated and approved by the FDA.
A biosimilar drug is developed to be highly similar to the FDA-approved biologic and must have no clinically meaningful differences. Patients must have the same physical response to the biosimilar as they would to the biologic. However, the biosimilar may have differences in the clinically inactive components of the drug.
Biosimilars are not generic drugs. The active ingredient in a small-molecule drug can be recreated exactly. Biosimilar drugs are more complex and therefore must meet the “highly similar” standard.
Biologics in cancer treatment can be used to flag cancer cells for destruction by the immune system. In many cases, the drugs kill fewer healthy cells than other treatments or are less toxic. Other biologics can reduce side effects. One class known as colony-stimulating factors (CSFs) encourage bone marrow to grow and divide.
Biologics and biosimilars represent some of the most important treatments for cancer patients.