Aptamer Therapeutics

The nucleic acid RNA comprises a sequence of bases (A/U/G/C) and is a copy of genetic information that functions as a mold (template) in synthesizing proteins. However, RNA, a single-stranded nucleic acid, is also characterized by its ability to form a variety of three-dimensional structures according to the particular sequence. Aptamers are nucleic acid molecules that utilize this structural plasticity to inhibit or control the activity of a target protein by binding to the protein, and aptamer therapeutics are aptamers that have been developed for pharmaceutical use.

What's RNA Aptamer?
RNA is composed of 4 element bases, A, U, G and C, and aptamers are formed by single strand RNA chains.
Single strand RNAs are generally unstable in solution and in vivo, and thereby tend to form tertiary structures by base-pairing.
RNA aptamer folded in specific tertiary structure its target protein.

A feature of aptamers is the shape-capturing that forms a three-dimensional structure which fits the shape of the target protein so as to bind to that protein. An antibody recognizes six to ten amino acid sequences on the surface of proteins. The manner in which aptamers bind to target proteins is different from that of antibodies.
Although both aptamer therapeutics and antibody drugs are molecular-targeted drugs, aptamer therapeutics has the following advantages over antibody drugs:

  • Higher binding affinity to target proteins
  • Fewer limitations as to targets
  • Easier chemical modification
  • Production by chemical synthesis
  • Lower antigenicity

Reviews of the characteristics of aptamers as middle molecules
Aptamers as therapeutic middle molecules

Aptamer Drug Discovery Technology

Aptamers are obtained through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technique. First, an RNA pool of random sequences (chemical library) is prepared; then, RNA molecules that bind to the target proteins as bait are pulled out of the pool. The sequences of these RNA molecules are amplified and fishing is repeated. Through this process, RNA molecules that bind tightly to target proteins are isolated. The resulting RNA molecules are aptamers.

The Ribomic Aptamer Refined Therapeutics (RiboART) system is the core of RIBOMIC drug discovery technology. Overall, it consists of technology, expertise, and experience in aptamer drug discovery and constitutes a variety of platforms that underlie new drug discoveries. By applying the RiboART system, it is possible to discover various new drugs essentially applicable to any target proteins, and not limited to one disease.

Business Model

RIBOMIC R&D generates first-in-class therapeutic aptamers using the RiboART system, which is a platform technology that essentially can be applied to any target proteins and is not limited to certain disease areas. Our R&D comprises two elements: collaboration with pharmaceutical companies and in-house drug discovery. Depending on the candidates for drug discovery, we develop a business whereby we conduct clinical studies and acquire POC in-house, and license out candidates to pharmaceutical companies.

Alliance Partners


  • Otsuka Pharmaceutical Co., Ltd. (contract for commercialization by RIBOMIC)
  • Fujimoto Pharmaceutical Corporation (capital alliance / licensing agreement)
  • Taisho Pharmaceutical Co., Ltd. (contract for joint research results)
  • Zenyaku Kogyo Co., Ltd. (capital alliance)
  • Mitsubishi Corporation Life Sciences Limited (collaborative research)
  • AJU pharma(licensing agreement)
  • Ajinomoto Co., Inc. (collaborative research)


  • Project Division of RNA Medical Science, The Institute of Medical Science, The University of Tokyo (collaborative research)
  • Juntendo University Hospital (collaborative research)
  • Faculty of Medicine, Osaka Medical College (collaborative research)
  • School of Medicine, Masaryk University, Czech Republic (collaborative research)
  • National Cerebral and Cardiovascular Center (collaborative research)
  • Faculty of Science and Engineering, Waseda University (collaborative research)
  • Nihon University Business, Research and Intellectual Property Center (collaborative research)
  • The Jikei University (collaborative research)
  • Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University(collaborative research)