Biologics

Biologics are medicines that living cells make, rather than medicines that chemists make in a reaction. Examples are antibodies that treat cancer or arthritis, insulin for diabetes and many vaccines. A biologic is a large and complex molecule, usually a protein, about a thousand times heavier than the molecule in a paracetamol tablet. It is too complex to build by chemistry, so living cells are used to build it.

Here is how it works in general. Scientists put the gene for the protein into living cells, such as bacteria, yeast or animal cells. The cells are grown in a bioreactor, a tank or a large plastic bag in which the cells are given food, oxygen and the right temperature for days or weeks. As they grow, the cells make the protein. The protein is then separated from the cells and purified, through filters and other steps. Finally it is tested, filled into vials or syringes and kept cold until it is used.

Making a biologic is harder to control than making a tablet. Small changes in the temperature or the food can change the protein slightly. So every step is measured and recorded by software, and each batch is tested before release. Most biologics must be injected, because the stomach would digest a protein that is swallowed. Most must also be kept between 2 and 8 °C all the way to the patient. Keeping a product within a set temperature at every step of its journey is called a cold chain.

Take, for example, a plant that makes an antibody medicine. Sensors in each bioreactor record the temperature, oxygen and acidity every few seconds, and software adjusts them to keep the cells growing as planned.

Consider a patient with rheumatoid arthritis who injects a biologic at home every two weeks. The medicine comes in a prefilled pen, one of the drug delivery devices made for medicines like this.

Say a vaccine maker in India ships doses to another country. The doses travel through cold-chain logistics, with a temperature logger in every box.

How is a biologic different from an ordinary drug, called a small-molecule drug? A small molecule is made by chemistry, and an exact copy, called a generic, can be made once the patent ends. A biologic made by a different company's cells can never be exactly the same. A close copy that is proven to work the same way is called a biosimilar. India is a large maker of both biosimilars and vaccines. The labs that study the cells use cell analysis instruments.