Medicinal chemists design, discover and develop small molecule drugs for various drug targets and diseases [1,2]. Recent advances in understanding disease development and new technologies such as high throughput screening (HTS), computer-aided drug design (CADD), combinatorial chemistry and microwave synthesis have markedly facilitated the drug design and discovery process [3-5]. The idea of creating new drugs is now moving from serendipity to rational design. Discovery of new drugs is carried out mainly by using processes, (1) screening of natural or synthetic compounds finding activity in a variety of biological screens, and (2) targeted approach which is characterized by a more rational approach, in which knowledge about specific enzymes and/or receptors are used as targets.

Current trends in medicinal chemistry efforts are moving towards the more targeted approach and this is being revolutionized and enhanced by genomics and proteomics. Target identification and validation are the first key stages in this process. Target validation involves demonstrating relevance and confirmation of target protein in a disease which can then be translated to animal models and this may involve the latest in gene targeting and expression techniques. Targets are the specific components existing naturally in cellular or molecular structure involved in cellular portions of the body. Changes or modification of these structures can lead to the pathology and may be responsible for the particular disease. The important molecular targets are mainly signal transduction pathways, cell surface receptors, and gene transcription targets. The target based approach can be effective in developing novel treatments for validated targets. The main concern of this approach is to avoid the side effects on healthy cells because some therapies are associated with significant toxicity.

The determination of the structures of putative macromolecular targets by X-ray is very important since it allows for insight into the geometry of enzyme’s active site. Knowledge of the three-dimensional structure of a target obtained using X-ray crystallography can lead to the rational drug design by understanding the target. The combination of modern structural biology and novel chemical technologies represent the most improved and productive means for the discovery of new drugs. This combination will continue to grow as a major source for drug discovery as more macromolecular structures becomes available. A recent success story in cancer therapeutics is the discovery of imatinib. The three-dimensional structure of tyrosine kinase (C-Abl) allowed medicinal chemists to develop the imatinib after refinement of the initial lead [6].

In the past few years several new targets have been identified and scientists will continue to discover new targets. Researchers are learning about the cell functions in great detailand this understanding has provided new insight into the cause of diseases. A very recent example in this regard is the identification of super enhancers. Young’s group discovered a set of gene regulators called super-enhancers that control cell state and identity [7]. Their study revealed that the disruption of BRD4 (bromodomain-containing protein 4) from the super enhancers significantly reduced MYC production in multiple myeloma (MM). They identified super-enhancers in different types of tumor cells such as glioblastomamultiforme (GBM) and non-small cell lung cancer (SCLC). They have shown that small molecule like JQ1 displaces BRD4 from super enhancers. Thus, development of more potent and selective small molecule drugs for the targeted inhibition of BRD4 could be a new opportunity for medicinal chemists [8]. In conclusion, we can only hope that this new era of targeted research will help medicinal chemists design better and more efficient drugs for various life threating diseases including cancer.