Aptamers as targeted therapeutics: current potential and challenges

Nucleic acid aptamers offer several advantages over traditional antibodies, but their clinical translation has been delayed by several factors, including insufficient potency, lack of safety data and high production costs. Here, Zhou and Rossi provide an overview of aptamer generation, focusing on recent technological advances and clinical development, as well as challenges and lessons learned. Nucleic acid aptamers, often termed 'chemical antibodies', are functionally comparable to traditional antibodies, but offer several advantages, including their relatively small physical size, flexible structure, quick chemical production, versatile chemical modification, high stability and lack of immunogenicity. In addition, many aptamers are internalized upon binding to cellular receptors, making them useful targeted delivery agents for small interfering RNAs (siRNAs), microRNAs and conventional drugs. However, several crucial factors have delayed the clinical translation of therapeutic aptamers, such as their inherent physicochemical characteristics and lack of safety data. This Review discusses these challenges, highlighting recent clinical developments and technological advances that have revived the impetus for this promising class of therapeutics.