Adeno-associated virus-based gene therapy points to a coming transformation in the treatment of people living with haemophilia, promising sustained bleed control and potential improvement in quality of life. Nevertheless, the consequences of introducing new genetic material are not trivial. The perceived benefits should not minimise the challenges facing patients in understanding the long-term risks and providing a valid and meaningful informed consent, whether in a research or clinical setting. Informed consent is a fundamentally important doctrine in both medical ethics and health law, upholding an individual’s right to define their personal goals and make their own autonomous choices. Patients should be enabled to recognise their clinical situation, understand the implications of treatment and integrate every facet of their life into their decision. This review describes informed consent processes for haemophilia gene therapy clinical trials, factors affecting patients’ decision making and the availability of patient-centred decision support interventions, to ensure that patients’ interests are being protected. Regulatory guidance has been published for physicians and manufacturers in haemophilia on informed consent, including for gene therapy, while best-practice recommendations for patient–physician discussions are available. In all settings, however, communicating and presenting highly technical and complex therapeutic information is challenging, especially where multiple barriers to scientific knowledge and health literacy exist. We propose several evidence-informed strategies to enhance the consent procedure, such as utilising validated literacy and knowledge assessment tools as well as participatory learning environments over an extended period, to ensure that patients are fully cognisant of the consent they give or deny. Further research is needed to define new, creative approaches for patient education and the upholding of ethical values in the informed consent process for gene therapy. The lessons learnt and approaches developed within haemophilia could set the gold standard for good practice in ensuring ethical preparedness amidst advances in genetic therapies. Plain language summary Improving the informed consent process for people living with haemophilia considering gene therapy. Gene therapy is the process of replacing faulty genes with healthy ones. In haemophilia, gene therapy involves introducing a working copy of the gene for the clotting factor that patients are missing. Following treatment, patients should begin producing their own clotting factor normally. However, people living with haemophilia (PwH) need to be fully informed regarding the potential benefits and risks of gene therapy and what this means for them, whether as part of a research study or routine medical care. Patients must be respected and supported to make decisions about their own health and wellbeing, recognising their legal and moral right to set personal goals and make treatment choices. For this to happen in practice, patients should be aware of their individual health needs, understand the effects of treatment and consider lifestyle preferences in relation to their decisions. This article attempts to describe how informed consent is obtained in haemophilia gene therapy clinical trials, what affects a patient’s ability to make decisions and the availability of information and support to respect and protect the interests of PwH. Regulators responsible for approving medical products have published guidance on informed consent for physicians and pharmaceutical manufacturers in haemophilia, including for gene therapy. Recommendations have been made about the best ways for PwH to discuss gene therapy with their physicians. Yet, poor communication of complex topics, such as gene therapy, can be problematic, especially if patients lack the skills and confidence to understand and discuss the science, or for physicians with limited time in clinic. We propose strategies to improve the consent process, so patients can feel more able to make informed decisions about new treatments. Further research is needed to find new, creative approaches for educating patients and ensuring that the informed consent process for gene therapy in haemophilia is ethical.
