By Johannes Kögel and Georg Marckmann.
Ethical criteria are essential for determining which patients should receive a pig heart transplant. These criteria—medical need, capacity to benefit, and patient choice—are designed to ensure a pathway to clinical trials that balances short-term outcomes with the long-term success of the therapy.
Xenotransplantation, the transplantation of organs across species boundaries, has already seen a few cases of humans receiving pig organs under exceptional permission from authorities, such as the FDA in the United States. Two patients who received pig hearts survived for six and eight weeks, respectively. This limited success may be attributed to the poor overall health status of the patients prior to transplantation.
To evaluate the efficacy of xenotransplantation as a viable alternative to human organ transplantation in a systematic and valid way, clinical trials will be necessary. Since these trials will shape the future of this therapy, the criteria for patient selection must differ from those used in established therapies.
By proposing a multicriteria approach to patent selection, we hereby expand the current guidelines formulated by regulatory bodies such as the WHO, the EMA, or the FDA.
It should be stated upfront that once xenotransplantation demonstrates efficacy in clinical trials, patients with the greatest medical need—those who require an organ urgently to survive—should be prioritized. However, to accurately assess xenotransplantation as an alternative to allotransplantation, patients in comparable health conditions are necessary for reliable results. If only patients in critical medical conditions, like the first two recipients of transgenic heart xenotransplantation, are selected, poor outcomes are likely, irrespective of the proper functioning of the xenograft, thereby potentially stalling the progress of xenotransplantation.
It’s crucial to acknowledge that clinical trials are not intended to guarantee effective treatment; rather, they aim to test new treatment approaches. In the case of heart transplantation, where failure often means death, the risk is particularly high. Therefore, it’s vital that patients who choose to participate can provide informed consent. This consent is severely limited for patients in poor health or those who have, due to prior non-compliance, forfeited their chances for alternative treatments, such as allotransplantation or an artificial heart. This issue is particularly relevant when psychosocial assessments place patients in a vulnerable position, further restricting their options.
Autonomous decision-making requires the possibility to choose between options, in this case having the choice between different treatment alternatives. The ideal candidates for heart xenotransplantation clinical trials would be those who choose this risky – but also promising – path over other treatments, whether because they lack the patience for the waiting list, refuse a human organ transplant, have a personal motivation to contribute to medical research, or any other personal reason.
This approach strikes a balance between the risks of experimental treatment, the long-term potential of an innovative therapy, and the basic principles of social fairness.
Authors: Johannes Kögel, Michael Schmoeckel, Georg Marckmann
Affiliations: LMU München
Competing interests: None declared
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