Drugs obtained with recombinant DNA technology. About 150 biopharmaceutical drugs were approved till 2003 for marketing in USA and EU, further 500 biopharmaceuticals are now in clinical trials for diseases ranging from cancer to cardiovascular and infectious diseases. The majority of the first approved products were either unmodified monoclonal antibodies or simple replacement proteins. Modifications of native proteins allowed obtaining therapeutic proteins with improved pharmacokinetics and biodistribution. Therapeutic monoclonal antibodies play growing role at the biopharmaceuticals market.