Practical and Statistical Considerations for the Long Term Follow‐Up of Gene Therapy Trial Participants

Study sponsors and market authorization holders are required by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) to enroll patients administered a gene therapy product, whether in a trial setting or post‐licensure, in a long term follow‐up safety study to continue the safety assessments of their product. These follow‐up studies range between 5 and 15 years after dosing. This unprecedented duration of engagement with patients and caregivers raises logistical challenges that will require innovation and collaboration across sponsors and regulators. In this paper we delineate some of the key considerations for designing long term follow‐up protocols in the gene therapy setting, with an eye toward platform and master protocol approaches, and offer guidance for innovative operational and statistical methods that can help assess the safety profile and durability of response for these novel therapeutics.