The SOSA Approach and Analog Design

The most popular strategy in drug design is the synthesis of analogs of existing active molecules in order to further improve desired properties and to alleviate liabilities. The objective is to start with known active principles and, by various chemical transformations, prepare new molecules (in certain cases referred to as me-too compounds ) for which an increase in potency, a better specific activity profile, improved safety, or a formulation that is easier to handle by physicians and nurses or more acceptable to the patient are claimed [40,41]. 

In the pharmaceutical industry, motivations for analog design are often driven by competitive and economic factors. Indeed, if the sales of a given medicine are high and the company is found in a monopolistic situation, protected by patents and trademarks, other companies will want to produce similar medicines, if possible with some therapeutic improvements. They will, therefore, use the already commercialized drug as a lead compound and search for ways to modify its structure and some of its physical and chemical properties while retaining or improving its therapeutic properties. 

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