Biological and biosimilar drugs Medicines that are derived from living cells/organisms are known as biological medicines. They consist of of highly complex molecular entities difficult to characterize. Certain degree of variations might found among biological medicines due to variation of the biological system and manufacturing process. A medicine that is very similar and clinically equivalent to a biological medicine is known as biosimilar medicine. Reference or originator medicine is an already approved biological medicine from which a biosimilar active medicine is derived. The biological product is highly similar to the reference product not withstanding minor differences in clinically inactive components; and 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. Biosimilar medicines are not the same as generic medicines, which contain simpler chemical structures and are identical, in terms of molecular structure, to their reference drugs [1].