Older Adults in Cancer Clinical Trials
While much of the national dialogue about diversity in clinical trials has focused on the inclusion of underserved populations, communities of color, and women, recent FDA guidance turned its attention to the inclusion of older adults — those over 65 years of age — in clinical research. While most cancer trials do not have an upper age limit for exclusion, adults 75 years of age and older are underrepresented in cancer clinical trials.
Cancer can affect anyone at any age, but certain populations are at higher risk than others. Cancer is a disease generally associated with age, with the number of cancer cases projected to multiply due to a rapidly aging U.S. population.
Older patients can sometimes have co-morbidities that may restrict their ability to participate in clinical trials. Eighty percent of adults 65 and over have at least one chronic condition, according to the National Council on Aging. Some eligibility criteria have become commonly accepted over time or used as a template across trials without clear scientific or clinical rationale. The FDA has published guidance on how to broaden eligibility criteria in order to understand the risks and benefits in a population that is more likely to use the drug in real-world scenarios.
Older patients are also more likely to be taking medications, which could impact the pharmacokinetics or effectiveness of a treatment. It can also influence the occurrence of side effects. Even if they are not taking other medications, there may be important differences in efficacy in older adult patients.
The clinical trial population should be representative of the intended population expected to take the drug, should it be approved. In the case of older patients, this can pose a challenge for enrollment. Research sites may consider consulting with geriatricians, geriatric oncologists, social and behavioral scientists with expertise in treating older adults. These experts may have insights and considerations to make it easier to recruit and support these patients.
Older adults may have specific challenges in accessing research sites. For example, urban academic medical centers may be more difficult to reach than community-based settings. Research sites may need to provide accommodations for patients with physical impairments such as limited sight, mobility, or hearing. Caregivers may need additional support.
Where feasible, remote monitoring approaches can offer useful alternatives. But these accommodations should be outlined in the protocol.
Patient-Centered Protocol Design
To facilitate the enrollment of older adults in cancer trials, sponsors may consider flexible approaches to trial design. This may include an open-label safety study that can enroll and analyze an older adult population separately in a parallel arm of a trial. The FDA also suggested stratifying study populations by age.
To support patient-centered clinical trial design, sponsors should consider perspectives of older adults, seeking input from patients and advocacy groups, as well as input from those caring for older adults such as clinicians and caregivers. This information can inform the design of the clinical trials, such as in assuring meaningful endpoints are selected, as well as in the conduct of the trial, such as in facilitating enrollment and retention of older adults.
The FDA advises sponsors and drug developers that “older adults, including those with physiological decline, should be enrolled in all phases of clinical trials when they can be safely and ethically enrolled.” There are several considerations in including these patients. But a successful result can be a better understanding of the benefits and risks of cancer treatments in this population.
 Singh H, Kanapuru B, Smith C, et al., 2017, FDA Analysis of Enrollment of Older Adults in Clinical Trials for Cancer Drug Registration: A 10-Year Experience by the U.S. Food and Drug Administration, JCO, 35:15 suppl, 10009-10009