Non-Ig antibody is a kind protein structural domain ,which has dense structure and thermal stability, independent variable unit, different from the immunoglobulin (Ig) domain structure of the protein structure. The history of non-Ig antibody can be dated back to 1997, the professor Shohei Koide invented the world's first similar-antibody using Phage Display (Phage library Display technology), and then transfer to Adnexus company in Boston. The Adnexus company developed a kind of antitumor drug using the similar-antibody and finished the preclinical trials including pharmacodynamics, safety evaluation in animals and was acqured by the bristol-myers squibb (BMS) to $430 million in 2007. Between 2006-2008, a similar level of hundreds of millions of dollars of transactions (pharmaceutical companies mergers and acquisitions of non-Ig antibody research and development enterprise) happened six times. At present, there are still a few similar-antibody research and development enterprise (such as Molecular Partners) operation independently, and active in the pharmaceutical industry abroad.

The biological macromolecular drugs developed by this kind of technology can adapt to the situation of our country, the reason is that protein after directed evolution and transformation can produce considerable binding ability specificly with monoclonal antibody and can be expressed largely by prokaryotes system avoiding the key factors for the industrialization of the monoclonal antibody drug: production cumbersome and expensive. While non-Ig antibody is not used to identify antigen protein naturely, so you must artificial design and build large capacity variation library, and screen efficiency against a particular disease targets to find effective drug precursor. The key technical bottlenecks for Similar-antibody drug research and development are existed in the development of the earliest filter link, rather than the later period of production. Which is the significant difference characteristics from monoclonal antibody drug development .