Freeline Therapeutics Holdings plc, a clinical-stage biotechnology company, develops transformative adeno-associated virus (AAV) vector-mediated gene therapies for patients suffering from inherited systemic debilitating diseases. Its advanced product candidate is FLT180a, a gene therapy product candidate that is in Phase 1/2 dose-finding clinical trials in adult males for the treatment of hemophilia B. The company’s products also include FLT190, which is in dose-escalating Phase 1/2 clinical trials for the treatment of Fabry disease; FLT201, a liver-directed gene therapy product candidate to treat type 1 Gaucher disease; and FLT210, a liver-directed gene therapy product candidate for the treatment of hemophilia A. In addition, it has research programs in various indications for systemic gene therapy. The company was founded in 2015 and is headquartered in Stevenage, the United Kingdom.