Developmental Therapeutics and the Design of Clinical Trials

New techniques in biotechnology and the use of biological response modifiers in cancer treatment have made it apparent that there are differences in developmental therapeutics for biotherapy, in contrast to drug development. Over the past 25 years, more than one million chemicals have been tested as anticancer agents, but less than 50 have reached the clinic as commercial pharmaceuticals. Perhaps ten of these drugs can be classed as moderately effective; the rest are only marginally useful and all can be highly toxic. With the discovery of monoclonal antibodies and conjugates thereof, the exploitation of bioengineering to produce purified, characterized lymphokines/cytokines and other biologicals, and further information on the mechanism of action of these natural molecules, the rate of development for biological therapeutics has risen dramatically. Because oftheir selectivity and with their implicit biological diversity, new approaches are needed to efficiently bring biotherapy to the clinic.