The disparity grew larger among older patients: Those 75 years or older accounted for 29 percent of patients with CML, but only 4 percent of trial participants.
Dr. Kanapuru also highlighted some encouraging insights from this analysis. Among patients aged 65 to 74 years, the proportion enrolled in lymphoma (excluding CLL) and CML trials essentially mirrored the reported incidence of blood cancers in this age group. In MM and CLL trials, the proportion enrolled in the 65-74 age group was higher than the reported incidence in this group. However, adults older than 75 years were still underrepresented in FDA clinical trials, despite the high number of diagnoses of incident hematologic cancers in this age group.
She noted that there are multiple barriers to enrolling older adults in clinical trials. For example, trial exclusion criteria often prohibit people with a history of previous cancers or comorbid or coexisting illnesses, which older adults are more likely to have, compared with younger individuals.
“Doctors may hesitate to enroll these older patients because they aren’t sure how they will tolerate investigational medications,†Dr. Kanapuru said, also citing the heterogeneity of the older population as a reason for their underrepresentation. “You can have one 75-year-old who is healthy and another person of the same age who is frail and has a lot of coexisting illnesses,†she said.
Study limitations include its retrospective design and variance in the data collected in the SEER database.
The authors report no financial conflicts.
Reference
Kanapuru B, Singh H, Myers A, et al. Enrollment of older adults in clinical trials evaluating patients with hematologic malignancies – The Food and Drug Administration (FDA) experience. Abstract #861. Presented at the 2017 American Society of Hematology Annual Meeting, December 11, 2017; Atlanta, GA.