Strategies for the discovery of therapeutic aptamers.

IMPORTANCE OF THE FIELD: Therapeutic aptamers are synthetic, structured oligonucleotides that bind to a very broad range of targets with high affinity and specificity. They are an emerging class of targeting ligand that show great promise for treating a number of diseases. A series of aptamers currently in various stages of clinical development highlights the potential of aptamers for therapeutic applications. AREAS COVERED IN THIS REVIEW: This review covers in vitro selection of oligonucleotide ligands, called aptamers, from a combinatorial library using the Systematic Evolution of Ligands by Exponential Enrichment process as well as the other known strategies for finding aptamers against various targets. WHAT THE READER WILL GAIN: Readers will gain an understanding of the highly useful strategies for successful aptamer discovery. They may also be able to combine two or more of the presented strategies for their aptamer discovery projects. TAKE HOME MESSAGE: Although many processes are available for discovering aptamers, it is not easy to discover an aptamer candidate that is ready to move toward pharmaceutical drug development. It is also apparent that there have been relatively few therapeutic advances and clinical trials undertaken due to the small number of companies that participate in aptamer development.