ABSTRACT
These variations are the biological differences among the trial patients. Although factors such as age, gender, education or socioeconomic status, smoking habit, weight, sexual orientation, and underlying disease characteristics at the baseline may contribute to the variation among patients, one of the most important reasons is the genetic or genomic variations among the trial participants. As early as in 1990,
O’Brien and Dean (1997) found the genes that infer protection against HIV infection. In addition, a correlation between the variability in survival of the HIV-infected subjects with their genotypes was reported by Winkler et al. (1998). Excellent reviews on inheritance and drug response and on pharmacogenomics can be obtained from the works of Weinshilboum (2003) and Evans and McLeod (2003), respectively.
