Scientists have made great strides against cancer, yet a longstanding problem remains unsolved: the lack of older adult participants in clinical trials. Researchers have acknowledged the underrepresentation of older patients for a decade, but little has changed, according to an article by City of Hope physicians in the May issue of Journal of Clinical Oncology.

Arti Hurria argues that cancer clinical trials must include more elderly patients. (Photo by p.cunningham)

“People over the age of 65 account for six out of 10 cancer cases, and there is an overwhelming amount of evidence showing that older adults react differently to cancer drugs,” said Arti Hurria, M.D., co-author of the article and director of City of Hope’s Cancer and Aging Research Program. “Their low rate of participation in cancer clinical trials means that doctors have less data about drugs’ efficacy and toxicity in older adults.”

Co-written with second-year hematology/oncology fellow Kevin Scher, M.D., the paper indicated that almost 60 percent of American cancer patients are over 65 years old, but this age group represents only a third of the clinical trial population.

In many clinical studies, the number of participants older than 75 is so low it is not reported — although this group makes up about 30 percent of patients with cancer.

“This problem is essentially a Catch-22,” said Hurria. “Older adults are underrepresented in clinical trials, in part because of concerns that these patients are at higher risk of treatment toxicity. However, the purpose of these clinical trials is to guide the Food and Drug Administration’s approved dose and schedule of the drugs, including that of older adults.”

Previous recommendations supported the enrollment of more older adults in trials, yet enrollment rates have stayed relatively stagnant over the past decade.

In the paper, Hurria and Scher presented several recommendations for improvement.

They call for a mandate to include more older adults in drug trials, similar to the Pediatric Research Equity Act of 2003, which gave the Food and Drug Administration the authority to mandate pediatric trials for drugs used primarily in children and adolescents. Since the legislation’s passage, several studies have produced important data on drugs related to childhood diseases.

“The bar should be raised to require the age distribution of [trial] participants to mirror the age distribution of patients with the disease,” they wrote.