ABSTRACT
The drug discovery and development process is long and often lled with unforeseeable hurdles. The major factor in selecting a promising drug candidate is the potential benet it provides in treating a given disease or syndrome. All benecial effects of drug, however, are counterbalanced by safety considerations since all therapeutics have adverse effects. This chapter discusses quantitative approaches to early drug development safety. These approaches differ from those in later drug development and in the postmarket phase in which greater numbers of subjects are treated. In early drug development, there is a strong reliance on biomarkers for both efcacy and safety evaluations on account of small numbers of subjects. Regulatory approval standards require larger numbers of subjects to demonstrate differences from control groups and rely on evidence of patients being made to feel better or live longer and occasionally on the presence of a surrogate marker for efcacy.
