Differential treatment effect between younger and older adults for new cancer therapies in solid tumors supporting US Food and Drug Administration approval between 2010 and 2021.

Older adults remain under-represented in oncology registration trials. Significant differences in outcomes by age group were uncommon in individual trials and pooled analyses. However, clinical trial participants differ from real-world patients older than 65 years, and increased enrollment and ongoing research into differential treatment effects by age are needed.