Usefulness of prestudy assessment of patient willingness to undergo tissue biopsy for correlative studies in a melanoma vaccine trial

Abstract

Background

Performing biopsies for correlative studies in cancer trials raises ethical and regulatory concerns and may impact trial accrual negatively. However, strategies to address these concerns remain largely unexplored.

Purpose

We sought to assess the perceived risk of mandatory tissue biopsies to be performed for research purposes as part of a clinical trial of a melanoma vaccine by administering a pretrial accrual assessment questionnaire in the population of interest. Furthermore, we explored how such survey data may be used to address potential concerns of regulatory and funding organizations that may not be able to assess the risks of those biopsies.

Method

A total of 91 melanoma patients, similar to potential participants in a melanoma vaccine pilot study, scored their willingness, on a 9-point Likert scale, to participate in vaccine trials involving no skin biopsy versus a skin biopsy resulting in a 3-, 6-, or 12-cm scar. The vaccine trial was performed with skin biopsies leaving a 6-cm scar. Accrual rate was assessed and that accrual was compared to the accrual of two similar vaccine trials without biopsy requirements.

Results

A total of 95% of the participants expressed willingness to enter a vaccine trial (likely to highly likely). This proportion decreased to 74%, 63%, and 59%, respectively, for vaccine trials requiring skin biopsy leaving a 3-, 6-, or 12-cm scar. The trial was designed with an estimated 40% decrease in accrual rate compared to prior studies (2 participants expected/month). The resulting trial with a 6-cm biopsy exceeded that accrual rate estimate and had a similar accrual rate to vaccine trials without a biopsy (4.1 vs 2.7–4.6 participants/month).

Limitations

Potential limitations of this study include the exclusion of some questionnaire responses and the post hoc nature of the analysis.

Conclusion

Willingness to participate in vaccine trials was decreased by the requirement for skin biopsy, but the size of the biopsy was less of a deterrent than expected. Findings from brief surveys may aid in risk assessment during regulatory review, predict acceptability of tissue collection for correlative studies, and support regulatory approval and meeting accrual goals of the study.