Abstract
Summary. The benefits of prophylactic infusion of clotting factor in haemophilia A and B in delaying the onset of arthropathy are supported by retrospective data, but the possibility of selection bias and confounding factors cannot be ruled out by such studies. Many issues that have only been studied retrospectively require definitive data, including the optimal dose and infusion intervals, as well as when to start prophylaxis and when to stop it. Issues of cost‐effectiveness of prophylaxis, quality of life and treatment satisfaction of patients on prophylaxis and their families also require prospective data. To advance the evidence‐based approach in haemophilia treatment, ESPRIT (Evaluation Study on Prophylaxis: a Randomized Italian Trial), currently underway, is a prospective randomized 10‐year study that will compare the efficacy and safety of prophylaxis and on‐demand regimens in preventing joint deterioration and in reducing the number of bleeds in patients with severe haemophilia A.