Xagrid is indicated for the reduction of elevated platelet counts in at-risk essential-thrombocythaemia (ET) patients who are intolerant to their current therapy or whose elevated platelet counts are not reduced to an acceptable level by their current therapy. An at-risk patient An at-risk ET is defined by one or more of the following features: >60 years of age or; a platelet count >1000 x 109/l or; a history of thrombohaemorrhagic events.