Whilst adeno-associated viral (AAV) vectors show great promise as effective gene transfer platforms, they have been demonstrated to trigger both innate and adaptive immune responses. Paul Gissen, MD, PhD, UCL Great Ormond Street Institute of Child Health, London, UK, describes the challenge of immune-related adverse events caused by AAV vector-based gene therapy and strategies being investigated to address this. Today, most clinical trials involving AAV vector-based gene therapy screen patients to detect the presence of antibodies against viral vectors as part of the patient enrolment process. Dr Gissen also discusses issues around cytotoxicity and the ongoing development of immunomodulatory regimens currently being developed. This interview took place at the Advanced Therapies Congress & Expo 2021.