23.01 Introduction: Principles of Biologics and their use as Medicines.

Between 2008 and 2010, 8 of the most costly 20 medications were biologics. Biologics are medications that are produced by means of biological processes involving recombinant DNA (rDNA) technology. rDNA is a form of artificial DNA that is created by combining two or more sequences that would not normally occur together through the process of DNA replication. This is a very active area in medicine production.

The decoding of the human genome revealed that there are 30,000 different genes encoding possibly 50,000 different proteins as a result of alternative gene splicing and posttranslational modification and that disease may result when one of these proteins is defective or present in abnormally high or low concentration. This ability to identify many of the causes of disease has presented a number of targets for possible therapies. Further, recombinant DNA technology has allowed a new generation of protein-based medicines, termed biologics, to be developed to take advantage of these new targets. Protein-based therapies have a number of advantages over conventional small-molecule drugs. Biologics often serve a highly specific and complex set of functions that cannot be mimicked by simple chemical compounds and there is less potential for protein-based drugs to interfere with normal biological processes and cause side effects. Further, since the body naturally produces many of the proteins that are used as therapies, biologics are often well tolerated and are less likely to elicit immune responses.

Protein-based therapies come in three classes. Firstly, proteins, purified native or recombinant themselves are administered to remedy lesions resulting in disease; secondly, antibodies directed against important biochemical pathways have been developed and; thirdly new vaccines produced from molecules important in the disease process.