The 6.1 Issue of the American Journal of Bioethics Neuroscience (AJOB Neuroscience) is now hot off the presses with two target articles highlighting ethical issues behind the use of two very different therapeutic interventions: first-in-human trials to treat Parkinson’s disease using stem-cell based therapies and prescription stimulants to enhance motivation.
The Target Article “Ethical Criteria for Human Trials of Stem-Cell Derived Dopaminergic Neurons in Parkinson’s Disease”1 by Samia A. Hurst et al. discusses three specific considerations of a phase I(safety)-II (efficacy) clinical trial designed to test an experimental neurorestorative stem cell therapy for Parkinson’s disease. Parkinson’s disease is a result of the loss of dopamine-producing neurons in the substantia nigra, and significant depletion of dopamine leads to the tremors, rigidity, and difficulty initiating or halting movement that is often seen as the disease progresses. To compensate for the diminishing levels of the neurotransmitter, standard treatment relies on the drug levodopa, which is converted to dopamine in the body. Levodopa is not curative though, and for that reason, researchers are beginning to study the neurorestoration technique of dopamine-producing stem cells transplants2. As promising and groundbreaking as stem-cell therapy is, protecting human subjects will be of utmost importance as the therapies enter clinical trials.
Parkinson’s disease is progressive, meaning that patients could exhibit a wide spectrum of mild to debilitating symptomology. After considering the risk-to-benefit ratio of enrolling patients who have either just been diagnosed or are at an advanced state of the disease, the authors suggest that only patients with approximately less than 15 years to live with “moderately advanced” Parkinson’s disease should be enrolled.
The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.