Background: The discovery that short oligonucleotides, termed aptamers, can fold into
three-dimensional structures that allow them to selectively bind and inhibit the activity of pathogenic
proteins is now over 25 years old. The invention of the SELEX methodology heralded in an era in
which such nucleic acid-based ligands could be generated against a wide variety of therapeutic targets.
Results: A large number of aptamers have now been identified by combinatorial chemistry methods in
the laboratory and moreover, an increasing number have been discovered in nature. The affinities and
activities of such aptamers have often been compared to that of antibodies, yet only a few of these
agents have made it into clinical studies compared to a large and increasing number of therapeutic antibodies.
One therapeutic aptamer targeting VEGF has made it to market, while 3 others have advanced
as far as phase III clinical trials.
Conclusion: In this manuscript, we hope the reader appreciates that the success of aptamers becoming
a class of drugs is less about nucleic acid biochemistry and more about target validation and overall