A method of producing synergistic and enhanced efficacy in treating a disease in a subject includes providing an antibody, the antibody being a classic antibody or a modified biologic molecule that blocks a first target in the subject； providing a drug, the drug being a small molecule agent that blocks the first target or a second target in the subject； connecting the antibody and the drug with a linker to form an Antibody-Drug Synergism (ADS) compound； and treating the disease with the ADS compound. The linker is hydrolyzed in the subject over a certain time so that both the antibody and the drug exert their functions simultaneously, and the ADS compound confers better efficacy than either the antibody or the drug alone due to a synergism of the ADS compound.
