DRUG DISCOVERY LARGE MOLECULE DRUGS

Drugs From Discovery to Approval, Second Edition, By Rick Ng Copyright 2009 John Wiley Sons, Inc. 

Unlike the small molecule drugs (pharmaceuticals) described in Chapter 3, large molecule drugs (biopharmaceuticals) are mainly protein based. Another distinction is that these protein-based drugs are, in the main, similar to natural biological compounds found in the human body or they are fragments that mimic the active part of natural compounds. 

The discovery of pharmaceuticals commences with the scanning of hundreds of compounds, whether with actual materials (irrational approach) or virtual simulations (rational approach). To discover biopharmaceuticals, we have to examine the compounds within us, for example, hormones or other biological response modihers, and determine how they affect the biological processes. In some cases, we study pathogens such as the influenza virus or bacteria to derive the vaccines. In other cases, we copy these biological response modifiers and use them as replacement therapy. 

Biopharmaceuticals are becoming increasingly important. The reason is that they are more potent and specific, as they are similar to the proteins within the body and hence are more effective in treating our diseases. There are three major areas in which biopharmaceuticals are used as prophylactic (preventive, as in the case of vaccines), therapeutic (antibodies), and replacement (hormones, growth factors) therapy. Exhibit 4.1 presents selected statistics for biopharmaceuticals. 

Another term that is used for protein-based drugs is biologies. The FDA gives the following definition for biologies  

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Chapter 4 Drug Discovery Large Molecule Drugs... 

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