Clinically annotated specimens from cancer trial participants offer an opportunity to discover and validate pharmacogenomic findings. In a recent study published in the Journal of the National Cancer Institute, Moffitt Cancer Center researchers investigated patients’ rate of participation in pharmacogenomic clinical trials.

Pharmacogenomics is the study of heritable and somatic genomic variations associated with drug response, including the prediction of toxicity and effectiveness. The field holds the promise of providing objective ways to individualize therapy, especially in the treatment of cancer patients. An efficient strategy to conduct these studies is to incorporate pharmacogenomics into prospective cancer clinical trials, in particular large phase III studies.

To study heritable variations in the clinical trial setting, germline DNA is extracted from blood samples of study patients who provide consent to participate in this component of the clinical trial. This requires a high number of patients from all races and ethnic backgrounds willing to participate.

To better understand patient/institution factors that may contribute towards participation rates in the pharmacogenomic component of prospective cancer clinical trials, the study titled “Participation in Cancer Pharmacogenomic Studies: A Study of 8456 Patients Registered to Clinical Trials in the Cancer and Leukemia Group B (Alliance)” analyzed demographic and institutional information (CALGB/ CTSU site) from seven phase 3 trials that occurred between 2002 and 2013. The trials included 8,456 patients with either Hodgkin’s Lymphoma, gastric, colorectal, breast, pancreatic, colon or prostate cancers.

The results showed that most patients (81%) consented to participate in the trials’ pharmacogenomic component. However, the researchers found that site (CALGB vs CTSU) and “institutional diversity” were associated with participation.

“As the field of oncology moves to biomarker-driven therapy, there is a concern that important minority groups are being inadvertently left out of the very research that will find the ‘right’ marker to guide therapy for people in their community,” said in a news release Howard L. McLeod, PharmD, medical director of the DeBartolo Family Personalized Medicine Institute at Moffitt.

Results also showed that for both whites and nonwhites, patients from CALGB sites were more likely to participate when compared to patients from CTSU sites. However, as “institutional diversity” increased, the likelihood of participation in the pharmacogenomics component decreased for both white and nonwhite patients.

“This suggests that the infrastructure of the clinic is a driver of differences in enrollment in these biomarker studies, not merely a patient’s heritage,” explained McLeod.

According to the researchers, race alone does not explain participation. Factors at the institutional level also need to be considered.

Based on the findings the researchers indicate that there are a number of factors at the patient, physician, institution and community level that serve as incentives or hindrances for clinical trial participation, including beliefs and attitudes, awareness, opportunities and resources.