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Shufeng ZhouShu-Feng Zhou, M.D., Ph.D., is a professor, associate vice president for global medical development, associate dean for international research, and chair of the Department of Pharmaceutical Sciences at the College of Pharmacy at the University of South Florida.

With the consistent decline in drug production over the past years, pharmaceutical companies strive to find alternative means to manufacture and market therapeutic drugs. In an attempt to negate high manufacturing costs and lengthy timelines, researchers and clinicians look to drug repositioning as a means of recreating new drugs from older ones with novel functionalities and better efficacy. Successfully repositioned drugs such as Viagra have hit the market with exponential pharmaceutical revenue records.

Researchers have estimated that the cost of developing a single new drug from scratch may induce a deficit greater than $800 million with the projected duration of development to be over the course of ten to seventeen years. According to recent studies, there are two main justifications attributed to the decrease in safe and marketable drugs on retail shelves. Primarily, conservative drug development strategies function to create novel therapeutic targets coupled with substances that alter target activity, which is typically prolonged, expensive, and involves experimental risk and lengthy clinical cross-referencing. Secondarily, productivity reduction is noted by the absence of systemic evaluation in addition to indications at the target site and throughout the phase of development, which affects the drugs’ marketability. To minimize superfluous time and money spent manufacturing, establishing, and marketing new drugs that may only exhibit minor composition or esthetic alterations, scientists have established a modification system that has long served to inculcate faster, more reliable methods to enhance drug manufacturing termed “drug repositioning” or “drug repurposing.”

The premise of drug repositioning functions in terms of the methodologies implemented in the quest of discovering new uses for existing drugs. Drug coincidence, or “serendipity” as termed by some authors, arises from unintentional mishaps in the drug remodeling process which can be exemplified in iconic cases of drugs such as sildenafil—commonly known as Viagra—and thalidomide—commonly known as Thalomid. While complete de novo synthesis of these drugs would have endured an exorbitant financial pitfall, drug remodeling enabled synthesis of these drugs for a fraction of the cost with revenues surmounting that of costly technological approaches. Statistical compilations indicate that gross revenue attributed to thalidomide, a drug repositioned for multiple myeloma, exceeded $271 million in 2003, and the drug repositioned for erectile dysfunction, sildenafil, or Viagra, exhibited $1.88 billion within the same year.

In today’s day and age, drug repositioning is quickly making its way to mainstream use worldwide. Technologically, pharmaceutical companies have utilized such mechanisms to explore and implement the quick turnover of drug manufacturing via the novel technologies associated with drug repositioning. As time progresses, a rapid increase in scientific and clinical manufacturing methodologies seems to emerge with equal attention geared towards the development of both drug-derived repositioning as well as disease-derived repositioning.

Learn more about drug repositioning at the 2013 Annual Meeting and Exposition short course Drug Repositioning in the Postgenomic Era.

Do you think drug repositioning will continue as an important approach to drug discovery?