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 verbrinacogene setparvovec (FLT180a), a gene therapy product candidate that is in Phase 1/2 clinical trials in adult males for the treatment of hemophilia B. The company's products also include FLT190, which is in Phase 1/2 clinical trial for the treatment of Fabry disease; and FLT201, a liver-directed gene therapy product candidate to treat type 1 Gaucher disease and is under Phase 1/2 clinical trial. 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.