Xenotransplantation Clinical Trials: Should Patients with Diminished Capacity be Permitted to Enroll?

Before xenotransplantation clinical trials begin, it is essential to establish clear and equitable participant selection criteria. Selection criteria have been suggested in the literature, as well as in a proposed kidney xenotransplantation phase 1 clinical trial.1-4 In each, inclusion criteria is predicated on patients possessing clinical decision-making capacity. Ensuring informed consent for xenotransplantation clinical trials with patients who have decision-making capacity is recognized as complex for the following reasons: the possibility of therapeutic misconception, potential for xenozoonosis, and the potentially burdensome requirement for lifelong biosurveillance.5, 6 Informed consent for enrollment in a xenotransplantation trial with adult persons who have diminished capacity would involve additional complexities. By diminished capacity, we mean to describe someone who—for various medical reasons—does not have the ability to provide informed consent. To our knowledge, no xenotransplantation investigator, nor the proposed kidney xenotransplantation phase I clinical trial in the United States, currently proposes including persons with diminished capacity. Nonetheless, the topic has been broached, and we believe it requires additional independent scrutiny.