Early-Phase Cancer Trials Show More Diversity in 2022 Compared to 2000


Diversity in patient populations, including age, race, ethnicity, and underrepresented regions, have increased in early-phase National Cancer Institute-sponsored trials.

Compared to 2000, there was a greater proportion of diverse patients included in National Cancer Institute (NCI)-sponsored early-phase clinical trials, including patients who were older, racially and ethnically diverse, and who lived in historically underrepresented regions of the United States, according to a statement from the American Association for Cancer Research (AACR). The results of the study were presented at the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved in Orlando, Florida, from September 29, 2023, to October 2, 2023.

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“Early-phase clinical trials, which primarily evaluate the safety of new therapies, have historically had insufficient representation of racial minorities, women, elderly patients, and [individuals] from lower socioeconomic strata, among other groups,” Maria Farooq, MBBS, a clinical fellow at the NCI, said in the statement. “This has limited the generalizability of trial results and increases the chance that important safety issues might be missed, which could further widen disparities in health care outcomes...The lack of diversity in early-phase clinical trial accrual also limits underrepresented patients’ access to cutting-edge therapies only available in the clinical trial setting,”

The study authors sought to compare the demographic data of patients in the NCI-sponsored phase 1, phase 1/2, and phase 2 clinical trials between 2000 and 2022, aiming to assess trends within early-phase clinical trials. They used data from the NCI Cancer Therapy Evaluation Program and early-phase oncology clinical trial database, according to the statement. In the analysis, the study authors observed a significant change in the age, race, ethnicity, and geographic locations of those enrolled in these early-phase clinical trials over the study time period.

For age group, investigators found that from 2000 to 2003, approximately 5.9% of patients enrolled in these trials were aged 75 to 84 years compared to 12.3% for the 2020 to 2022 time period. Furthermore, the proportions increased from 24.2% to 32.9% in the 65 to 74 years of age range and decreased from 59.8% to 46.5% for those aged 40 to 64 years, respectively.

For those in minority groups, the proportion of Hispanic/Latinx individuals enrolled in trials increased from 4.2% to 6.9% from the 2000 to 2003 period and the 2020 to 2022 period, respectively. There were also increases for Asian/Pacific Islander enrollment from 2.5% to 5.4%, Non-Hispanic Black enrollment from 6.3% to 7.1%, and unknown or unspecified race or ethnicity from 3.3% to 7.6%, respectively. The non-Hispanic White group decreased from 83.7% to 72.9%.

Additionally, the proportion of individuals in the South or West of the United States increased from 2000 to 2003 and 2020 to 2022. In the South, the proportion increased from 29.1% to 30.9%, and in the West, from 7.9% to 18.2%. In the Northeast, the proportion decreased from 23.9% to 20.8% and, in the Midwest, from 24.4% to 19.4%.

Furthermore, the proportion of individuals who enrolled in trials closer to home increased from 2000 to 2003 and 2020 to 2022. Those who enrolled in a trial within 50 miles of their home increased from 46.5% to 64.5%, respectively, and those who travelled more than 200 miles decreased from 16.1% to 8.3%, respectively.

“Over the period evaluated, NCI-sponsored early-phase cancer clinical trials became more representative of the broader patient population,” Farooq said in the statement. “These results are encouraging, but there is still substantial room for improvement in this area...Broadly, we believe that further increasing outreach and accessibility to marginalized communities, as well as strengthening trust between these communities and research institutions, may continue to improve enrollment diversity now and in the future.”

The study was observational, therefore, investigators could not make conclusions about the causes of these trends. It is possible that the changes were influenced by cancer types and investigational therapies that were studied in each time period.

Farooq added that the greater availability to these trials, changes in eligibility criteria, and increases in the number of smaller sites offering clinical trials could have impacted the diversity of individuals in these studies.


NCI-sponsored cancer clinical trials have become more diverse over past two decades. AACR. September 29, 2023. Accessed September 29, 2023. Email.

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