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Gene therapy may warrant long-term follow-up of research subjects due to the risk of delayed adverse events. The FDA cites potential risks of adverse outcomes following exposure to human gene therapy products that are summarized as follows1:
“Integration activity” of the gene therapy product: Raises the potential for disruption of critical host genes that could result in malignancies.
Genome editing activity: Genome editing-based products impart their biological activity through site-specific changes in the human genome, but may also have off-target affects that raise the risk of malignancies and impaired gene function.
Prolonged expression: A gene therapy product where the therapeutic gene encodes growth factors, raising the potential for unregulated cell growth and malignancies.
Latency: A gene therapy product using, for example, a herpesvirus, has the potential for reactivation from latency, raising the risk of delayed adverse events related to a symptomatic infection.
Establishment of persistent infections: Gene therapy products that are replication-competent viruses and bacteria, such as listeria-based bacterial vectors, have the potential to cause persistent infections in immunocompromised patients.
1. FDA. Long-Term Follow-Up After Administration of Human Gene Therapy Products. Draft Guidance for Industry. July 2018. Available at: https://bit.ly/2O4C3VE
Financial Disclosure: Author Melinda Young, Medical Writer Gary Evans, Editor Jill Drachenberg, Editor Jesse Saffron, Editorial Group
Manager Terrey L. Hatcher, Physician Editor Lindsay McNair, MD, MPH, MSBioethics, and Nurse Planner Kay Ball, PhD, RN, CNOR, CMLSO, FAAN, report no consultant, stockholder, speaker’s bureau, research, or other financial relationships with companies having ties to this field of study.