A Randomized Trial of Thymoglobulin to Prevent Chronic Graft versus Host Disease in Patients Undergoing Hematopoietic Stem Cell Transplantation from Unrelated Donors

Background: Chronic Graft versus Host Disease (cGVHD) is a common long term complication of bone marrow transplantation. cGVHD causes chronic illness in people whose bone marrow disease has been cured, resulting in a severe decrease in quality of life and increased risk of death. The Canadian Blood and Marrow Transplant Group (CBMTG) outlines a key study of a preventive treatment that promises to ameliorate or prevent suffering. Complications of cGVHD occur despite the use of current treatments which are therefore ineffective and which have serious side-effects. Prevention is a better strategy. The most promising strategy is the administration of antithymocyte globulin (ATG, Thymoglobulin?) just prior to transplantation. The proposal: Patients will be randomized to receive, or not to receive, Thymoglobulin?, and the incidence and severity of graft versus host disease will be compared between the two study groups. Information Regarding Graft Versus Host Disease: a)Bone marrow transplantation cures otherwise fatal bone marrow disorders b)The bone marrow contains the cells for the development of the immune system and those for the development of other blood cells. c)The recipient adopts the immune system of the donor. d)The donor?s immune system may attack the recipient?s tissues. When the attack is against the diseased marrow this is termed Graft versus Leukemia reaction (GVL) and is responsible in a major way for the success of the transplant. On the other hand, when the donor immune system attacks the recipient?s normal tissues (Graft Versus Host Disease, GVH) the result is organ damage with death or chronic long term illness. e)Graft Versus Host Disease may be Acute (aGVHD), occurring within the first 100 days, or it may be Chronic (cGVHD), occurring beyond 100 days. cGVHD may be fatal but more often it is debilitating, the degree of illness being compounded by the side effects of the drugs used to treat it.