Advanced pancreatic cancer clinical trials: The continued underrepresentation of older patients

Older patients make up the majority of patients with pancreatic cancer, with a median age of 71 years at diagnosis. However, older patients are underrepresented in clinical trials in pancreatic cancer. This study investigates trends in age distribution of patients enrolled in clinical trials for advanced pancreatic cancer over time, and examines outcomes and toxicity in older patient subgroups from two studies conducted by Eastern Cooperative Oncology Group and American College of Radiology Imaging Network (ECOG-ACRIN) in this disease.

16,042 patients from 38 phase III clinical trials for locally advanced or metastatic pancreatic adenocarcinoma published between 1997 and 2016 were identified and included in this analysis. Outcomes and toxicity by age were examined in two of the trials, ECOG-ACRIN trials E2297 and E6201, which included a total of 1146 patients.

The median age across the trials was 62.7 years; median ages for individual trials ranged from 57 years to 66 years. Weighted linear regression showed no significant change in median age over time. Combined analysis of the two ECOG-ACRIN trials demonstrated higher rates of fatigue, thrombocytopenia, and infection in those ≥75 years compared with those <75 years, but despite this showed no difference in overall survival (OS) or progression-free survival (PFS) (OS: 5.7 vs. 5.6 months and PFS: 2.8 vs 3.5 months).

Enrollment of older adults in phase III pancreatic cancer clinical trials has not increased over time, despite increasing number of older patients seen in clinic. Increased efforts are needed to enhance enrollment of older patients in clinical trials, and to promote trials specifically for older patients, in order to improve the evidence base for treating this patient population.