Provided is a drug system design method, comprising selecting a target moiety specifically binding to a target of interest, and connecting the target moiety to a biologically active moiety and/or connecting the target moiety to a biologically inert moiety. Also provided are a test kit, a drug kit or a pharmaceutical composition including a biologically inert drug comprising the target moiety and the biologically inert moiety and a biologically active drug comprising the target moiety and the biologically active moiety, wherein the biological inert drug and the biologically active drug target a same target. Also provided is a method for using the drugs or the pharmaceutical composition to treat diseases such as those related to ED-B.
