biologic therapy

Biologic therapy uses drugs made by living cells rather than synthesised by ordinary chemistry. A traditional small-molecule drug is like a simple machine part stamped out in a factory; a biologic is more like a delicate organic product grown in a bioreactor. These are large, complex protein molecules, far bigger and more intricate than typical pills.

The family includes monoclonal antibodies, fusion proteins, therapeutic hormones such as insulin, clotting factors, interferons and interleukins. They are produced using recombinant DNA technology, where engineered cells are programmed to manufacture a specific human protein. Because they are large proteins, they would be digested if swallowed, so they are almost always given by injection or infusion, and they often have long half-lives.

Two practical features set biologics apart. First, their size and protein nature can make the immune system react against the drug itself, reducing effect or causing reactions. Second, because they cannot be copied by simple chemistry, generic versions are impossible; instead, highly similar follow-on products called biosimilars are made and tested separately. Biologics are central to modern cancer and immune-disease treatment but are typically expensive and storage-sensitive.