Disparities in Clinical Trial Enrollment for Hematologic Malignancies

There is increasing recognition that Black, Hispanic, Native American, and other populations are under-represented in therapeutic clinical trials relative to the prevalence of hematologic malignancies in these populations. To understand the extent of such disparities in pivotal trials leading to regulatory drug approval, investigators identified 61 U.S. trials conducted in adult patients from 2011 to 2021. Patients with leukemia, multiple myeloma, and myelodysplastic and myeloproliferative disorders were included in the analysis; those with lymphomas were excluded. U.S. population-based incidence and mortality rates for these cancers were obtained from the National Cancer Institute's SEER and other national databases. County-level population representation and geographic location of clinical trial sites also were identified.

Of the 61 trials, 41 (67%) reported data on race of the enrollees. Of 13,731 patients, 81.6% were white, 3.8% Black, 9.1% Asian/Pacific Islander, 0.12% American Indian or Alaska Native, and 1.5% other. Ethnicity was reported in only 20 trials, with Hispanic patients accounting for 4.7% of enrollees. Geographically, trials were predominately available in the Northeast, Southeast, and eastern Midwest regions; there was a notable lack of trial availability in many regions with high hematologic cancer mortality rates for minority populations. A striking observation is that although 27.4% of U.S. myeloma diagnoses are in Black patients, these patients make up only 4.7% of enrollees in pivotal myeloma trials.