摘要：Although extensive research addresses minorities’ low participation in clinical research, most focuses almost exclusively on therapeutic trials. The existing literature might mask important issues concerning minorities’ participation in clinical trials, and minorities might actually be overrepresented in phase I safety studies that require the participation of healthy volunteers. It is critical to consider the entire spectrum of clinical research when discussing the participation of disenfranchised groups; the literature on minorities’ distrust, poor access, and other barriers to trial participation needs reexamination. Minority participation in clinical trials is an important topic in public health discussions because this representation touches on issues of equality and the elimination of disparities, which are core values of the field. DURING THE PAST 25 YEARS, there have been national efforts in the United States to increase the representation of minorities in clinical trials. 1 Discussions about how to enhance participation have generated an extensive literature that addresses the low participation of minorities, especially African Americans. Significant scholarly interest exists in elucidating why these groups have historically been underrepresented in human participant research. Although current participation rates do not fully represent the overall population of minorities in the United States, progress is being made. Currently, African Americans and Hispanics make up 12.4% and 15.8% of the US population, respectively. 2 A recent report indicates that minorities represent almost 30% of those enrolled in clinical trials sponsored by the National Institutes of Health (NIH) and that African Americans now make up approximately 15% of those minority participants. 3 There is still room for improvement, however, with significant enrollment issues continuing to affect the representation of Hispanics in clinical trials. One report estimated Hispanic representation in NIH studies at 7.6% of all research participants, 3 and a report on industry-sponsored studies found that only 3% of those participants were Hispanic. 4 Increasing the participation of all minorities in clinical trials is critical for the production of knowledge about new therapies because having diverse research participants can improve the generalizability of medicine. Additionally, minority participation in clinical trials is an important topic in public health discussions because this representation touches on issues of equality and the elimination of disparities, which are core values of the field. Despite academic interest in the topic, most of the focus has been on the benefits that minority groups can experience from clinical trial participation. There has been little discussion about the involvement of minorities in higher risk or lower benefit research. Currently, there are no databases aggregating demographic data from all clinical trials—neither those sponsored by NIH nor those sponsored by the pharmaceutical industry. Examining the entire spectrum of clinical research is important because the goals of clinical trials—as well as the benefits and risks—differ according to a novel therapy's stage of development. Clinical trials generally proceed in 3 phases. Phase I studies are safety studies, used to establish appropriate doses for subsequent clinical testing and to generate data on adverse events. These studies are primarily conducted by using healthy volunteers who derive no direct health benefits from their participation. Phase II studies are designed to provide preliminary information about the efficacy of a new treatment as well as further information about its safety, using a few hundred participants with the targeted disease. Participants may derive health benefits from phase II studies, but only about one half of investigational therapies are shown to have promise in phase II trials. 5 Phase III clinical trials require several thousand volunteers with the targeted disease, usually involve the randomization of participants into experimental and placebo arms of the study, and can take from 2 to 4 years to complete. These studies measure the efficacy of an investigational treatment and sometimes a comparative benefit. With an 80% success rate, these trials are believed to offer important health benefits to participants. 5 Despite the critical differences between study phases—especially between the goals of and types of participants in phase I and phase III studies—discussions about the representation of minorities in clinical trials virtually ignore these distinctions. Most of the literature focuses exclusively on phase III therapeutic trials. As a result, the existing literature may mask important issues concerning minorities’ participation in clinical trials. We propose that the representation of minorities in clinical trials changes dramatically when taking a broader view of study participation. Phase I safety studies elicit a different set of findings regarding the representation of minorities in nontherapeutic clinical trials. Most notably, data provided to the authors by industry as part of a larger empirical project suggest that minorities might actually be overrepresented in studies involving healthy volunteers ( Table 1 ). Because there is currently no comprehensive source of data about industry clinical trials or early phase trials at NIH, we used the phase I participation data provided by representative sources in industry to question the assumptions commonly held about minorities’ participation in clinical trials. The literature on distrust, poor access, and other barriers to participation needs to be reexamined. We argue that it is critical to consider the entire spectrum of clinical research when discussing the participation of disenfranchised groups. TABLE 1 Demographics of Phase I Participants at 1 Northeastern and 1 Southwestern US Facility: Minority Participation in Clinical Research, June 2010 Phase I Facilities Demographic Factor Northeast Southwest Total Total participants 13 612 16 747 30 359 Gender, no. (%) Men 9241 (67.9) 9306 (55.6) 18 547 (61.1) Women 4371 (32.1) 7441 (44.4) 11 812 (38.9) White, non-Hispanic, no. (%) 4735 (34.8) 6230 (37.2) 10 965 (36.1) All non-White, no. (%) 8877 (65.2) 10 517 (62.8) 19 394 (63.9) African American 5755 (42.3) 1027 (6.1) 6782 (22.3) Asian 423 (3.1) 99 (0.6) 522 (1.7) Hispanic 1970 (14.5) 9196 (54.9) 11 166 (36.8) Other 729 (5.4) 195 (1.2) 924 (3.0) Open in a separate window Note . The data are from 2 companies’ “active” participant databases as queried in June 2010. The companies’ identities are confidential as part of their participation in a broader, ongoing empirical project. We selected them on the basis of their large participant databases and the high volume of studies they conduct for industry, which makes them representative of phase I trials conducted in the United States. Facilities with smaller databases of participants report similar demographic data.
