Sirtex is supporting an extensive clinical study programme of randomised controlled studies. They are the largest studies of their kind in the world and are designed to define the optimal role for SIR-Spheres® Y-90 resin microspheres in the treatment of various inoperable liver tumours; and to further investigate the safety and effectiveness of SIR-Spheres Y-90 resin microspheres with chemotherapy and biologic agents.